ARTICLE | doi:10.20944/preprints202203.0360.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: EpCAM; monoclonal antibody; recombinant antibody; colorectal carcinoma
Online: 28 March 2022 (10:11:34 CEST)
The epithelial cell adhesion molecule (EpCAM) is a cell surface glycoprotein, which is widely expressed on normal and cancer cells. EpCAM is involved in cell adhesion, proliferation, survival, stemness, and tumorigenesis. Therefore, EpCAM is thought to be a promising target for cancer diagnosis and therapy. In this study, we established anti-EpCAM monoclonal antibodies (mAbs) using the Cell-Based Immunization and Screening (CBIS) method. We characterized them using flow cytometry, western blotting, and immunohistochemistry. One of the established recombinant anti-EpCAM mAbs, recEpMab-37 (mouse IgG1, kappa), reacted with EpCAM-overexpressed Chinese hamster ovary-K1 cells (CHO/EpCAM) or a colorectal carcinoma cell line (Caco-2). In contrast, recEpMab-37 did not react with EpCAM-knocked out Caco-2 cells. The KD of recEpMab-37 for CHO/EpCAM and Caco-2 was 2.0 × 10-8 M and 3.2 × 10-8 M, respectively. In western blot analysis, recEpMab-37 detected EpCAM of CHO/EpCAM and Caco-2 cells. Furthermore, recEpMab-37 could stain formalin-fixed paraffin-embedded colorectal carcinoma tissues by immunohistochemistry. Taken together, recEpMab-37, established by CBIS method, is useful for detecting EpCAM in various applications.
REVIEW | doi:10.20944/preprints202010.0607.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: immunohistochemistry; phage display; monoclonal antibody
Online: 29 October 2020 (10:25:14 CET)
Immunohistochemistry is a widely used technique for research and diagnostic purposes that relies on the recognition by antibodies of antigens expressed in tissues. However, tissue processing and particularly formalin fixation affect the conformation of these antigens through the formation of methylene bridges. Although antigen retrieval techniques can partially restore antigen immunoreactivity, it is difficult to identify antibodies that can recognize their target especially in formalin-fixed paraffin-embedded tissues. Most of the antibodies currently used in immunohistochemistry have been obtained by animal immunization; however, in vitro display techniques represent alternative strategies that have not been fully explored yet. This review provides an overview of phage display-based antibody selections using naïve antibody libraries on various supports (fixed cells, dissociated tissues, tissue fragments, and tissue sections) that have led to the identification of antibodies suitable for immunohistochemistry.
ARTICLE | doi:10.20944/preprints202309.0906.v3
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: HER2; cancer-specific monoclonal antibody; screening; epitope; flow cytometry
Online: 28 November 2023 (03:35:30 CET)
Overexpression of human epidermal growth factor receptor 2 (HER2) in breast and gastric cancers is an important target for monoclonal antibody (mAb) therapy. All therapeutic mAbs, including anti-HER2 mAbs, exhibit adverse effects probably due to the recognition of antigens expressed in normal cells. Therefore, tumor-selective or specific mAbs can be beneficial in reducing the adverse effects. In this study, we established a novel cancer-specific anti-HER2 antibody, named H2Mab-250/H2CasMab-2 (IgG1, kappa). H2Mab-250 reacted with HER2-positive breast cancer BT-474 and SK-BR-3 cells. Importantly, H2Mab-250 did not react with non-transformed normal epithelial cells (HaCaT and MCF 10A) and immortalized normal epithelial cells in flow cytometry. In contrast, most anti-HER2 mAbs including H2Mab-119 (IgG1, kappa) reacted with both cancer and normal epithelial cells. Furthermore, a core-fucose deleted IgG2a-type H2Mab-250 (H2Mab-250-mG2a-f) could trigger the antibody-dependent cellular cytotoxicity activity to BT-474, but not to HaCaT cells. Furthermore, H2Mab-250-mG2a-f exhibited an in vivo antitumor effect against BT-474 xenograft. Immunohistochemical analysis demonstrated that H2Mab-250 possesses much higher reactivity to the HER2-positive breast cancer tissues compared to H2Mab-119, and did not react with normal tissues, including heart, breast, stomach, lung, colon, kidney, and esophagus. The epitope mapping demonstrated that the Trp614 of HER2 domain IV mainly contributes to the recognition by H2Mab-250. H2Mab-250 could contribute to the development of chimeric antigen receptor-T or antibody-drug conjugates without adverse effects for breast cancer therapy.
REVIEW | doi:10.20944/preprints202311.0307.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: monoclonal antibodies; variants resistance; bispecific antibodies; engineered antibodies; antiviral therapy
Online: 6 November 2023 (10:38:14 CET)
Monoclonal antibody (mAb) therapy has revolutionized the treatment of various diseases, including cancer and autoimmune disorders. However, the emergence of SARS-CoV-2 variants, as well as other pathogenic variants, poses challenges in maintaining the therapeutic efficacy of mAbs. In this mini review article, we aim to explore the strategies to overcome variants resistance in mAb therapy against viral infections. Firstly, we discuss the mechanisms through which variants can evade the neutralizing effects of mAbs. Understanding these mechanisms is crucial in developing targeted approaches to combat resistance. Next, we delve into the strategies being pursued to address variants resistance. These include developing new mAbs or antibody cocktails that target multiple epitopes, engineering mAbs with improved binding affinities or enhanced neutralizing capabilities, and exploring alternative therapeutic modalities such as bispecific antibodies or antibody-drug conjugates. Furthermore, we highlight the role of computational modeling and artificial intelligence in predicting variant escape mutations and aiding in the design of more effective mAbs. Additionally, we examine the importance of continuous surveillance and monitoring of emerging variants to inform treatment strategies. This article emphasizes the urgent need for proactive approaches to tackle variants resistance in mAb therapy. By combining innovative design strategies, computational modeling, and vigilant surveillance, we can maintain the therapeutic effectiveness of mAbs and stay ahead in the battle against evolving pathogens and viral infections.
ARTICLE | doi:10.20944/preprints202203.0015.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; monoclonal antibody; esophageal cancer
Online: 1 March 2022 (10:32:33 CET)
CD44 is a cell surface glycoprotein, which is widely expressed on normal and cancer cells. CD44 is involved in cell adhesion, migration, proliferation, survival, stemness, and chemo-resistance. Therefore, CD44 is thought to be a promising target for cancer diagnosis and therapy. In this study, we established anti-CD44 monoclonal antibodies (mAbs) by immunizing mice with CD44v3-10 ectodomain and screening using enzyme-linked immunosorbent assay. We then characterized them using flow cytometry, western blotting, and immunohistochemistry. One of the established clones (C44Mab-46; IgG1, kappa) reacted with CD44s-overexpressed Chinese hamster ovary-K1 cells (CHO/CD44s) or esophageal squamous cell carcinoma (ESCC) cell lines (KYSE70 and KYSE770). The KD of C44Mab-46 for CHO/CD44s, KYSE70, and KYSE770 was 1.1×10-8 M, 4.9×10-8 M, and 4.1×10-8 M, respectively. C44Mab-46 detected CD44s of CHO/CD44s and KYSE70, and CD44v of KYSE770 in western blot analysis. Furthermore, C44Mab-46 strongly stained esophageal squamous carcinoma cells in immunohistochemistry using formalin-fixed paraffin-embedded ESCC tissues. Taken together, C44Mab-46 is very useful for detecting CD44 in various applications.
COMMUNICATION | doi:10.20944/preprints202311.0805.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: mouse CXCR3; monoclonal antibody; CBIS method
Online: 14 November 2023 (05:37:03 CET)
C-X-C motif chemokine receptor 3 (CXCR3, CD183) is a G-protein-coupled receptor for CXCL9, CXCL10, and CXCL11. CXCR3 signaling induces chemotaxis of immune cells to inflammation sites and promotes inflammation in inflammatory diseases. Various mouse models to mimic the pathogenesis of each disease have been developed to understand mechanisms and evaluate therapeutics for these diseases. Although CXCR3 is an attractive target to suppress inflammation, anti-CXCR3 therapeutic agents have not been approved. In this study, we established a novel anti-mouse CXCR3 (mCXCR3) monoclonal antibody, Cx3Mab-4 (rat IgG1, kappa), using the Cell-Based Immunization and Screening method. Flow cytometric analysis demonstrated that Cx3Mab-4 bound to mCXCR3-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR3) cells, but did not react to parental CHO-K1 cells. The dissociation constant of Cx3Mab-4 was determined as 1.3 × 10-9 M, indicating that Cx3Mab-4 possesses a high affinity to mCXCR3-expressing cells. Cx3Mab-4 could be useful for targeting CXCR3-expressing cells in preclinical mouse models.
COMMUNICATION | doi:10.20944/preprints202311.0501.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: mouse CXCR4; monoclonal antibody; CBIS method
Online: 8 November 2023 (15:52:54 CET)
The CXC chemokine receptor 4 (CXCR4, CD184) is a member of the G protein-coupled receptor family that is expressed in most leukocytes. Overexpression of CXCR4 is associated with poor prognosis in not only hematopoietic malignancy but also solid tumors. Because CXCR4 is an attractive target for tumor therapy, reliable preclinical murine models using anti-CXCR4 monoclonal antibodies (mAbs) have been warranted. This study established a novel anti-mouse CXCR4 (mCXCR4) mAb using the Cell-Based Immunization and Screening (CBIS) method. Flow cytometric analysis showed that an anti-mCXCR4 mAb, Cx4Mab-1 (rat IgG2a, kappa), recognized mCXCR4-overexpressed Chinese hamster ovary-K1 (CHO/mCXCR4) cells and endogenously mCXCR4-expressing mouse myeloma P3X63Ag8U.1 (P3U1) cells. Furthermore, Cx4Mab-1 did not recognize mCXCR4-knockout P3U1 cells. The dissociation constants of Cx4Mab-1 for CHO/mCXCR4 and P3U1 were determined as 6.4 × 10−9 M and 2.3 × 10-9 M, respectively, indicating that Cx4Mab-1 possesses a high affinity to both endogenous and exogenous mCXCR4-expressing cells. These results indicate that Cx4Mab-1 could be a useful tool for preclinical mouse models.
ARTICLE | doi:10.20944/preprints202301.0153.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44v6; monoclonal antibody; colorectal cancer
Online: 9 January 2023 (09:02:06 CET)
CD44 is a cell surface glycoprotein, and its isoforms are produced by the alternative splicing with the standard and variant exons. The CD44 variant exon containing isoforms (CD44v) are overexpressed in carcinomas. CD44v6 is one of the CD44v, and its overexpression predicts poor prognosis in colorectal cancer (CRC) patients. CD44v6 plays critical roles in CRC adhesion, proliferation, stemness, invasiveness, and chemoresistance. Therefore, CD44v6 is a promising target for cancer diagnosis and therapy for CRC. In this study, we established anti-CD44 monoclonal antibodies (mAbs) by immunizing mice with CD44v3-10-overexpressed Chinese hamster ovary-K1 (CHO) cells. We then characterized them using enzyme-linked immunosorbent assay, flow cytometry, western blotting, and immunohistochemistry. One of the established clones (C44Mab-9; IgG1, kappa) reacted with a peptide of variant 6-encoded region, indicating that C44Mab-9 recognizes CD44v6. Furthermore, C44Mab-9 reacted with CHO/CD44v3-10 cells or CRC cell lines (COLO201 and COLO205) by flow cytometry. The apparent KD of C44Mab-9 for CHO/CD44v3-10, COLO201, and COLO205 was 8.1 × 10−9 M, 1.7 × 10−8 M, and 2.3 × 10−8 M, respectively. C44Mab-9 detected the CD44v3-10 in western blotting, and partially stained the formalin-fixed paraffin-embedded CRC tissues in immunohistochemistry. Collectively, C44Mab-9 is useful for detecting CD44v6 in various applications.
ARTICLE | doi:10.20944/preprints202307.1288.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: EphB4; monoclonal antibody; Cell-Based Immunization and Screening; immunohistochemistry
Online: 19 July 2023 (04:40:06 CEST)
The erythropoietin-producing hepatocellular carcinoma (Eph) receptors are the largest receptor tyrosine kinases family. EphB4 is essential for cell adhesion and motility during embryogenesis. Pathologically, EphB4 is overexpressed and contributes to poor prognosis in various tumors. Therefore, sensitive monoclonal antibodies (mAbs) should be developed to predict the prognosis for multiple tumors with high EphB4 expression, including breast and gastric cancers. This study aimed to develop highly sensitive and specific anti-EphB4 mAbs for several applications using the Cell-Based Immunization and Screening (CBIS) method. EphB4-overexpressed Chinese hamster ovary (CHO)-K1 (CHO/EphB4) cells were immunized into mice, and we established an anti-EphB4 mAb (clone B4Mab-7), which is applicable for flow cytometry, western blotting, and immunohistochemistry. B4Mab-7 reacted with endogenous EphB4-positive breast cancer cell lines, MCF-7 and MDA-MB-468, but did not react with EphB4-knockout MCF-7 (BINDS-52) in flow cytometry. Dissociation constant (KD) values were determined to be 2.9 × 10‑9 M, 1.3 × 10‑9 M, and 3.3 × 10‑9 M by flow cytometric analysis for CHO/EphB4, MCF-7, and MDA-MB-468 cells, respectively. B4Mab-7 detected the EphB4 protein bands from breast cancer cells in western blotting, and stained breast cancer tissues immunohistochemistry. Altogether, B4Mab-7 demonstrated high sensitivity and specificity against EphB4 in various applications.
REVIEW | doi:10.20944/preprints201905.0326.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: stroke; antibody therapy; monoclonal antibody; inflammation; acid-sensing ion channel; receptor; growth factors
Online: 28 May 2019 (10:05:26 CEST)
Acute ischemic strokes are the third leading cause of death and the leading cause of neurological disability worldwide. The oxygen and glucose deprivation associated with ischemic strokes not only leads to neuronal cell death, but also increases the inflammatory response and decreases functional output of the brain. The only intervention approved by US Federal Drug and Food Administration for treatment of ischemic strokes is tissue plasminogen activator (tPA), however, such treatment can only be given within 4.5 hours of the onset of stroke-like symptoms. This narrow time-range limits its application, and it also might induce detrimental rather than beneficial effects to stroke patients by treatment of the tPA. In order to reduce the infarct volume of an acute ischemic stroke while increasing the time period for treatment, emerging therapies reveal great potential by targeting inflammation, growth factors, ion channels, and neurotransmitter receptors with monoclonal antibody (MAB). With successfully application in the treatment of cancer patient by MAB, in this review, we will focus on recent advances on stroke therapy by using MAB on the treatment of stroke by targeting inflammation, growth factors, ion channels, and neurotransmitter receptors. Therefore, developing specific MAB targeting the signaling pathway of stroke will contribute to stroke therapy.
ARTICLE | doi:10.20944/preprints202304.0452.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44 variant 3; monoclonal antibody; flow cytometry; immunohistochemistry
Online: 17 April 2023 (10:44:35 CEST)
Cluster of differentiation 44 (CD44) promotes tumor progression through the recruitment of growth factors, and the acquisition of stemness, invasiveness, and drug resistance. CD44 has multiple isoforms including CD44 standard (CD44s) and CD44 variants (CD44v), which have common and unique functions in tumor development. Therefore, the elucidation of each CD44 isoform’s function in tumor is essential for the establishment of CD44-targeting tumor therapy. We have established various anti-CD44s and anti-CD44v monoclonal antibodies (mAbs) through immunization of CD44v3–10-overexpressed cells. In this study, we established C44Mab-6 (IgG1, kappa), which recognized the CD44 variant 3-encoded region (CD44v3) determined by enzyme-linked immunosorbent assay. C44Mab-6 reacted with CD44v3–10-overexpressed Chinese hamster ovary (CHO)-K1 cells (CHO/CD44v3–10) or some cancer cell lines (COLO205 and HSC-3) by flow cytometry. The apparent KD of C44Mab-6 for CHO/CD44v3–10, COLO205, and HSC-3 was 1.5 × 10−9 M, 6.3 × 10−9 M, and 1.9 × 10−9 M, respectively. C44Mab-6 could detect the CD44v3–10 in western blotting, and stained the formalin-fixed paraffin-embedded tumor sections in immunohistochemistry. These results indicate that C44Mab-6 is useful for detecting CD44v3 in various experiments, and expected for the application of tumor diagnosis and therapy.
COMMUNICATION | doi:10.20944/preprints202303.0309.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mouse CCR6; monoclonal antibody; epitope; ELISA; SPR
Online: 16 March 2023 (14:13:28 CET)
CC chemokine receptor 6 (CCR6) is one of the members of G protein-coupled receptor (GPCR) family that is upregulated in many immune-related cells, including B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. Coordination between CCR6 and its ligand CC motif chemokine ligand 20 (CCL20) is deeply involved in the pathogenesis of various diseases, such as cancer, autoimmune diseases, and psoriasis. Therefore, CCR6 is an attractive target for therapy and is being investigated as a diagnostic marker for patients. In a previous study, we developed an anti-mouse CCR6 (mCCR6) monoclonal antibody (mAb), C6Mab-13 (rat IgG1, kappa), applicable for flow cytometry by immunizing a rat with N-terminal peptide of mCCR6. This study investigated the binding epitope of C6Mab-13 using enzyme-linked immunosorbent assay (ELISA) and surface plasmon resonance (SPR) methods with the synthesized point mutated-peptides within 1-20 amino acids region of mCCR6. In ELISA, C6Mab-13 lost the reaction to the alanine-substituted peptide of D11A. The epitope of C6Mab-13 was identified to be Asp11 in ELISA. Furthermore, in SPR analysis, the dissociation constants (KD) could not be calculated for G9A and D11A mutants due to lack of binding. The SPR analysis demonstrated that the C6Mab-13 epitope comprises Gly9 and Asp11. Taken together, the key binding epitope of C6Mab-13 was determined to be around Asp11 on mCCR6. Based on the epitope information, C6Mab-13 could be useful for further functional analysis of mCCR6 in future studies.
ARTICLE | doi:10.20944/preprints202303.0399.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44v9; monoclonal antibody; colorectal cancer
Online: 22 March 2023 (14:21:41 CET)
Cluster of differentiation 44 (CD44) is a type I transmembrane glycoprotein, and has been shown as a cell surface marker of cancer stem-like cells in various cancers. Especially, the splicing variants of CD44 (CD44v) are overexpressed in cancers, and play critical roles in cancer stemness, invasiveness, and resistance to chemotherapy and radiotherapy. Therefore, the understanding of the function of each CD44v is indispensable for the CD44-targeting therapy. CD44v9 contains the variant 9-encoded region, and its expression predicts poor prognosis in patients with various cancers. CD44v9 plays critical roles in the malignant progression of tumors. Therefore, CD44v9 is a promising target for cancer diagnosis and therapy. Here, we developed sensitive and specific monoclonal antibodies (mAbs) against CD44 by immunizing mice with CD44v3–10-overexpressed Chinese hamster ovary CHO-K1 (CHO/CD44v3–10) cells. We first determined their critical epitopes using enzyme-linked immunosorbent assay, and characterize their applications to flow cytometry, western blotting, and immunohistochemistry. One of the established clones, C44Mab-1 (IgG1, kappa) reacted with a peptide of the variant 9-encoded region, indicating that C44Mab-1 recognizes CD44v9. C44Mab-1 reacted with CHO/CD44v3–10 cells or colorectal cancer cell lines (COLO201 and COLO205) by flow cytometry. The apparent dissociation constant (KD) of C44Mab-1 for CHO/CD44v3–10, COLO201, and COLO205 was 2.5 × 10−8 M, 3.3 × 10−8 M, and 6.5 × 10−8 M, respectively. Furthermore, C44Mab-1 was able to detect the CD44v3–10 in western blotting, and endogenous CD44v9 in immunohistochemistry using colorectal cancer tissues. These results indicated that C44Mab-1 is useful for detecting CD44v9 not only in flow cytometry or western blotting but also in immunohistochemistry against colorectal cancers.
ARTICLE | doi:10.20944/preprints202310.1348.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: podocalyxin; PODXL; cancer-specific monoclonal antibody; defucosylated antibody; pancreatic cancer
Online: 20 October 2023 (11:46:59 CEST)
Podocalyxin (PODXL) overexpression is associated with poor clinical outcomes in various tumors. PODXL is involved in tumor malignant progression through the promotion of invasiveness and metastasis. Therefore, PODXL has been considered as a promising target of monoclonal antibody (mAb)-based therapy. However, PODXL also plays an essential role in normal cells such as vascular and lymphatic endothelial cells.Therefore, cancer-specificity or selectivity is required for the reduction of adverse effects on normal cells. Here, we developed an anti-PODXL cancer-specific mAb (CasMab), PcMab-6 (IgG1, kappa), by immunizing mice with soluble PODXL ectodomain derived from a glioblastoma LN229 cell.PcMab-6 reacted with the PODXL-positive LN229 cells, but not with PODXL-knockout LN229 cells in flow cytometry. Importantly, PcMab-6 recognized pancreatic ductal adenocarcinoma (PDAC) cell lines (MIA PaCa-2, Capan-2, and PK-45H), but did not react with normal lymphatic endothelial cells (LECs). In contrast, one of the non-CasMabs, PcMab-47 showed high reactivity to both the PDAC cell lines and LECs. Next, we engineered PcMab-6 into a mouse IgG2a type (PcMab-6-mG2a) and a humanized IgG1-type (humPcMab-6) mAbs, and further produced the core fucose-deficient types (PcMab-6-mG2a-f and humPcMab-6-f, respectively) to potentiate the antibody-dependent cellular cytotoxicity (ADCC). Both PcMab-6-mG2a-f and humPcMab-6-f exerted ADCC and complement-dependent cellular cytotoxicity in the presence of effector cells and complements, respectively. In the PDAC xenograft model, both PcMab-6-mG2a-f and humPcMab-6-f exhibited potent antitumor effects. These results indicated that humPcMab-6-f could apply to antibody-based therapy against PODXL-expressing pancreatic cancers.
ARTICLE | doi:10.20944/preprints202212.0392.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: CD44; CD44 variant 4; monoclonal antibody; flow cytometry; immunohistochemistry
Online: 21 December 2022 (07:40:21 CET)
CD44 has been known as a marker of tumor initiating cells, and plays pro-tumorigenic functions in many cancers. The splicing variants play critical roles in malignant progression of cancers by promoting the stemness, cancer cell invasion or metastasis, and resistance to chemo- and radiotherapy. To understand each CD44 variant (CD44v) function is essential to know the property of cancers and establishment of the therapy. However, the function of the variant 4-encoded region has not to be elucidated. Therefore, specific monoclonal antibodies (mAbs) against the variant 4 are indispensable for basic research, tumor diagnosis, and therapy. In this study, we established anti-CD44 variant 4 (CD44v4) monoclonal antibodies (mAbs) by immunizing mice with a peptide containing the variant 4-encoded region. We next performed flow cytometry, western blotting, and immunohistochemistry to characterized them. One of the established clones (C44Mab-108; IgG1, kappa) reacted with CD44v3-10-overexpressed Chinese hamster ovary-K1 cells (CHO/CD44v3-10). The KD of C44Mab-108 for CHO/CD44 v3-10 was 3.4 × 10−7 M. In western blot analysis, C44Mab-108 detected CD44v3-10 in the lysate of CHO/CD44v3-10 cells. Furthermore, C44Mab-108 stained formalin-fixed paraffin-embedded oral squamous carcinoma tissues in immunohistochemistry. These results indicated that C44Mab-108 is useful to detect CD44v4 in various applications.
ARTICLE | doi:10.20944/preprints202311.1444.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: residue detection; pretilachlor; monoclonal antibody; ic-ELISA
Online: 22 November 2023 (16:49:06 CET)
Pretilachlor is a chloroacetamide herbicide, mainly used for the control of weeds and broadleaf weeds in rice, and widely used in China. For the detection of residues of pretilachlor in the en-vironment and food, a highly sensitive and specific monoclonal antibody against pretilachlor was prepared, and the half maximum inhibitory concentration (IC50) of the monoclonal antibody was validated to be 31.47±2.35 μg/L. An indirect competitive ELISA (ic-ELISA) based on the antibody with a linear range of 6.25~100 μg/L was developed for the detection of pretilachlor residues in the environment and food crops. The specificity of the antibody was explained by computer simula-tions and experimental validation. No cross-reactivity of this monoclonal antibody to alachlor, acetochlor and metalaxyl, and it cross-reacted less than 3.0% to both butachlor and propisochlor. The limits of detection (LOD) for pretilachlor in lake, rice, and soil samples were 4.83~5.23 μg/L. The recoveries of all samples were 78.3%~91.3%. The ic-ELISA method was validated by high-performance liquid chromatography, thus, it can be used for residue detection of pretilachlor in the environment and grains.
ARTICLE | doi:10.20944/preprints202010.0494.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: HIV immunotherapy; photoimmunotherapy; photodynamic Therapy; porphyrin; phthalocyanine; HIV-infected cell; monoclonal antibody
Online: 23 October 2020 (14:55:47 CEST)
Different therapeutic strategies have been investigated to target and eliminate HIV-1-infected cells by using armed antibodies specific to viral proteins, with varying degrees of success. Herein, we propose a new strategy by combining photodynamic therapy (PDT) with HIV Env-targeted immunotherapy, and refer to it as HIV photoimmunotherapy (PIT). A human anti-gp41 antibody (7B2) was conjugated to two photosensitizers with different charges through different linking strategies; “Click” conjugation by using an azide-bearing porphyrin attached via a disulfide bridge linker with a drug-to-antibody ratio (DAR) of exactly 4, and “Lysine” conjugation by using phthalocyanine IRDye 700DX dye with average DARs of 2.1, 3.0 and 4.4. These photo-immunoconjugates (PICs) were compared via biochemical and immunological characterizations regarding the dosimetry, solubility, and cell targeting. Photo-induced cytotoxicity of the PICs were compared using assays for apoptosis, reactive oxygen species (ROS), photo-cytotoxicity, and confocal microscopy. Targeted phototoxicity seems to be primarily dependent on the binding of PS-antibody to the HIV antigen on the cell membrane, whilst being independent of the PS type. This is the first report of the application of PIT for HIV immunotherapy by killing HIV Env-expressing cells.
ARTICLE | doi:10.20944/preprints202305.1905.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44v10; monoclonal antibody; oral squamous cell carcinoma; immunohistochemistry
Online: 26 May 2023 (09:49:30 CEST)
CD44 is known as a cancer stem cell marker of head and neck squamous cell carcinoma (HNSCC) and plays a critical role in cancer malignant progression. Splicing variant isoforms of CD44 (CD44v) are overexpressed in cancers and considered a promising target for cancer therapy. Several monoclonal antibodies (mAbs) against CD44 have been developed by immunizing mice with CD44v3–10-overexpressed cancer cells. In this study, we characterized a novel clone, C44Mab-18 (IgM, kappa). C44Mab-18 reacted with CHO/CD44v3–10, but not with CHO/CD44s by flow cytometry. Enzyme-linked immunosorbent assay revealed that the epitope of C44Mab-18 is determined to be the border sequence between variant 10 and the constant exon 16-encoded sequence. Flow cytometry showed that C44Mab-18 recognizes HSC-3, an oral squamous cell carcinoma(OSCC) cell line. The apparent dissociation constant (KD) of C44Mab-18 for CHO/CD44v3–10 and HSC-3 was determined to be 1.6 × 10−7 M and 1.7 × 10−7 M, respectively. C44Mab-18 detected CD44v3–10, but not CHO/CD44s in western blotting. Furthermore, C44Mab-18 detected endogenous CD44v10 in immunohistochemistry using OSCC tissues. Taken together, C44Mab-18 is useful for detecting CD44v10 in flow cytometry and immunohistochemistry.
ARTICLE | doi:10.20944/preprints202307.0900.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: HER2; monoclonal antibody; ADCC; CDC; antitumor activity
Online: 13 July 2023 (09:23:17 CEST)
Breast cancer patients with high levels of HER2 (human epidermal growth factor receptor 2) expression had worse clinical outcomes. Anti-HER2 monoclonal antibody (mAb) is the most important therapeutic modality for HER2-positive breast cancer. We previously immunized mice with the ectodomain of HER2 to create the anti-HER2 mAb, H2Mab-77 (mouse IgG1, kappa). This was then altered to produce H2Mab-77-mG2a-f, an afucosylated mouse IgG2a. In the present work, we examined the reactivity of H2Mab-77-mG2a-f and antitumor effects against breast cancers in vitro and in vivo. BT-474, an endogenously HER2-expressed breast cancer cell line, was identified by H2Mab-77-mG2a-f with a strong binding affinity [a dissociation constant (KD): 5.0 × 10-9 M]. H2Mab-77-mG2a-f could stain HER2 of breast cancer tissues in immunohistochemistry and detect HER2 protein in western blot analysis. Furthermore, H2Mab-77-mG2a-f demonstrated strong antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) for BT-474 cells. MDA-MB-468, a HER2-negative breast cancer cell line, was unaffected by H2Mab-77-mG2a-f. Additionally, in the BT-474-bearing tumor xenograft model, H2Mab-77-mG2a-f substantially suppressed tumor development when compared to the control mouse IgG2a mAb. In contrast, the HER2-negative MDA-MB-468-bearing tumor xenograft model showed no response to H2Mab-77-mG2a-f. These findings point to the possibility of H2Mab-77-mG2a-f as a treatment regimen by showing that it has antitumor effects on HER2-positive breast tumors.
COMMUNICATION | doi:10.20944/preprints202303.0181.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: CCR6; monoclonal antibody; peptide immunization; flow cytometry; immunohistochemistry
Online: 9 March 2023 (13:45:12 CET)
CC chemokine receptor 6 (CCR6) is a member of the G protein-coupled receptor (GPCR) family that is highly expressed in B lymphocytes, effector and memory T cells, regulatory T cells, and immature dendritic cells. CCR6 has been revealed to have important functions in many pathological conditions, such as cancer, intestinal bowel disease, psoriasis, and autoimmune diseases. The only CCR6 chemokine ligand, CC motif chemokine ligand 20 (CCL20), is also involved in pathogenesis by interacting with CCR6. The CCL20/CCR6 axis is drawing attention as an attractive therapeutic target for various diseases. In this study, we developed novel monoclonal antibodies (mAbs) against human CCR6 (hCCR6) using the peptide immunization method, which are applicable to flow cytometry and immunohistochemistry. The established anti-hCCR6 mAb, clone C6Mab-19 (mouse IgG1, kappa), reacted with hCCR6-overexpressed Chinese hamster ovary-K1 (CHO/hCCR6), HepG2 (human liver carcinoma), and HuH-7 (human differentiated hepatoma) cells in flow cytometry. The dissociation constant (KD) of C6Mab-19 was determined as 3.0 × 10−10 M for CHO/hCCR6, 6.9 × 10−10 M for HepG2, and 1.8 × 10−10 M for HuH-7. Thus, C6Mab-19 could bind to exogenously and endogenously expressed hCCR6 with extremely high affinity. Furthermore, C6Mab-19 could stain formalin-fixed paraffin-embedded lymph node tissues from a patient with non-Hodgkin lymphoma by immunohistochemistry. Therefore, C6Mab-19 is suitable for detecting hCCR6-expressing cells and tissues, and could be useful for pathological analysis and diagnosis.
ARTICLE | doi:10.20944/preprints202305.0995.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44 variant 8; monoclonal antibody; gastric cancer; flow cytometry; immunohistochemistry
Online: 15 May 2023 (07:41:36 CEST)
Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. GC with peritoneal metastasis exhibits a poor prognosis due to the lack of diagnostic biomarkers and effective therapy. A comprehensive analysis of malignant ascites identified the genomic alterations and significant amplifications of cancer driver genes, including CD44. CD44 and its splicing variants are overexpressed in tumors, and play crucial roles in the acquisition of invasiveness, stemness, and resistance to treatments. Therefore, the development of CD44-targeting monoclonal antibodies (mAbs) is important for GC diagnosis and therapy. In this study, we immunized mice with CD44v3–10-overexpressed PANC-1 cells and established several dozens of clones that produce anti-CD44v3–10 mAbs. One of the clones (C44Mab-94; IgG1, kappa) recognized the variant-8-encoded region and peptide, indicating that C44Mab-94 is a specific mAb for CD44v8. Furthermore, C44Mab-94 could recognize CHO/CD44v3–10 cells, oral squamous cell carcinoma cell line (HSC-3), or GC cell lines (MKN45 and NUGC-4) in flow cytometric analyses. C44Mab-94 could detect the exogenous CD44v3–10 and endogenous CD44v8 in western blotting and stained the formalin-fixed paraffin-embedded gastric cancer cells in immunohistochemistry. These results indicate that C44Mab-94 is useful for detecting CD44v8 in various applications and is expected to be useful for the application of GC diagnosis and therapy.
ARTICLE | doi:10.20944/preprints202302.0437.v1
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: CD44; CD44 variant 7/8; monoclonal antibody; flow cytometry; immunohistochemistry
Online: 27 February 2023 (04:13:02 CET)
Cluster of differentiation 44 (CD44) has been investigated as a cancer stem cell (CSC) marker, and plays critical roles in tumor malignant progression. The splicing variants are overexpressed in many carcinomas, especially squamous cell carcinomas, and play critical roles in the promotion of tumor metastasis, the acquisition of CSC properties, and resistance to treatments. Therefore, each CD44 variant (CD44v) function and distribution in carcinomas should be clarified for the establishment of novel tumor diagnosis and therapy. In this study, we immunized mice with a CD44 variant (CD44v3−10) ectodomain and established various anti-CD44 monoclonal antibodies (mAbs). One of the established clones (C44Mab-34; IgG1, kappa) recognized a peptide which covers both variant 7 and 8-encoded region, indicating that C44Mab-34 is a specific mAb for CD44v7/8. Moreover, C44Mab-34 reacted with CD44v3–10-overexpressed Chinese hamster ovary-K1 (CHO) cells or oral squamous cell carcinoma (OSCC) cell line (HSC-3) by flow cytometry. The apparent KD of C44Mab-34 for CHO/CD44v3–10 and HSC-3 was 1.4 × 10−9 M and 3.2 × 10−9 M, respectively. C44Mab-34 could detect CD44v3–10 in western blotting, and stained the formalin-fixed paraffin-embedded OSCC in immunohistochemistry. These results indicate that C44Mab-34 is useful for detecting CD44v7/8 in various applications, and expected for the application of OSCC diagnosis and therapy.
ARTICLE | doi:10.20944/preprints202301.0581.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44 variant 5; monoclonal antibody; flow cytometry; immunohistochemistry
Online: 31 January 2023 (09:08:35 CET)
Pancreatic cancer exhibits a poor prognosis due to the lack of early diagnostic biomarkers and the resistance to conventional chemotherapy. CD44 has been known as a cancer stem cell marker, and plays tumor promotion and drug resistance in various cancers. Especially, the splicing variants are overexpressed in many carcinomas, and play essential roles in the cancer stemness, invasiveness or metastasis, and resistance to treatments. Therefore, the understanding of each CD44 variant (CD44v) function and distribution in carcinomas is essential for the establishment of CD44-targeting tumor therapy. In this study, we immunized mice with CD44v3–10-overexpressed Chinese hamster ovary-K1 (CHO) cells, and established various anti-CD44 monoclonal antibodies (mAbs). One of the established clones (C44Mab-3; IgG1, kappa) recognized peptides of the variant 5-encoded region, indicating that C44Mab-3 is a specific mAb for CD44v5. Moreover, C44Mab-3 reacted with CHO/CD44v3–10 cells or pancreatic cancer cell lines (PK-1 and PK-8) by flow cytometry. The apparent KD of C44Mab-3 for CHO/CD44v3–10 and PK-1 was 7.1 × 10−10 M and 1.9 × 10−9 M, respectively. C44Mab-3 could detect the exogenous CD44v3–10 and endogenous CD44v5 in western blotting, and stained the formalin-fixed paraffin-embedded pancreatic cancer cells, but not normal pancreatic epithelial cells in immunohistochemistry. These results indicate that C44Mab-3 is useful for detecting CD44v5 in various applications, and expected for the application of pancreatic cancer diagnosis and therapy.
COMMUNICATION | doi:10.20944/preprints202311.0216.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: CD44; CD44 variant 4; monoclonal antibody; epitope; enzyme-linked immunosorbent assay
Online: 3 November 2023 (06:38:38 CET)
CD44 is a type I transmembrane glycoprotein, and possesses various isoforms which are largely classified into CD44 standard and CD44 variant (CD44v) isoforms. Some variant-encoded regions play critical roles in tumor progression. However, the function of CD44 variant 4 (CD44v4)-encoded region has not been fully understood. Using peptide immunization, we developed an anti-CD44v4 mAb, C44Mab-108, which is useful for flow cytometry, western blotting, and immunohistochemistry. In this study, we determined the critical epitope of C44Mab-108 by enzyme-linked immunosorbent assay (ELISA). We used the alanine (or glycine)-substituted peptides of the CD44v4-encoded region (amino acids 271-290 of human CD44v3-10), and found that C44Mab-108 did not recognize the alanine-substituted peptides of D280A and W281A. Furthermore, these peptides could not inhibit the recognition of C44Mab-108 in flow cytometry and immunohistochemistry. The results indicate that the critical binding epitope of C44Mab-108 includes Asp280 and Trp281 of CD44v3-10.
COMMUNICATION | doi:10.20944/preprints202311.1910.v1
Subject: Medicine And Pharmacology, Other Keywords: ferret podoplanin; monoclonal antibody; epitope; PA scanning
Online: 29 November 2023 (16:08:28 CET)
In small animal models of severe acute respiratory syndrome coronaviruses (SARS-CoV and SARS-CoV-2) infection, ferrets (Mustela putorius furo) have been used to investigate the pathogenesis. Podoplanin (PDPN) is an essential marker in lung type I alveolar epithelial cells, kidney podocytes, and lymphatic endothelial cells. Monoclonal antibodies (mAbs) against ferret PDPN (ferPDPN) are useful for the pathological analyses of those tissues. We previously established an anti-ferPDPN mAb, PMab-292 using the Cell-Based Immunization and Screening (CBIS) method. In this study, we determined the critical epitope of PMab-292 using flow cytometry. The N-terminal ferPDPN deletion mutants analysis revealed that the Val34 is located at the N-terminus of the PMab-292 epitope. Furthermore, the PA tag-substituted analysis (PA scanning) showed that Asp39 is located at the C-terminus of PMab-292 epitope. The epitope sequence (34-VRPEDD-39) also exists between Val26 and Asp31 of ferPDPN, indicating that PMab-292recognizes the tandem repeat of the VRPEDD sequence of ferPDPN.
ARTICLE | doi:10.20944/preprints202308.1756.v2
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: PDPN; lung cancer; glioblastoma; monoclonal antibody; antitumor activities; mouse xenograft model; antibody-dependent cellular cytotoxicity
Online: 20 October 2023 (12:26:35 CEST)
We previously developed a highly sensitive and specific anti-PDPN mAb, LpMab-23 (mouse IgG1, kappa). In this study, we produced a humanized IgG1 version (humLpMab-23) and its defucosylated form (humLpMab-23-f) of an anti‑PDPN mAb to potentiate the ADCC activity. The humLpMab-23 could recognize PDPN‑overexpressed Chinese hamster ovary (CHO)-K1 (CHO/PDPN) and PDPN-positive PC-10 and LN319 cells by flow cytometry. Furthermore, we found that humLpMab-23-f exerted ADCC and complement-dependent cytotoxicity against CHO/PDPN, PC-10 and LN319 cells in vitro and exhibited potent antitumor activities in the xenograft models. These results indicated that humLpMab-23-f could be useful for an antibody treatment regimen for PDPN-positive human cancers.
ARTICLE | doi:10.20944/preprints202307.1961.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: fremanezumab; monoclonal antibody; calcitonin gene-related peptide; trigeminal ganglion; CGRP receptor; immunofluorescence; rat; migraine pain
Online: 28 July 2023 (09:27:07 CEST)
Treatment with the anti-CGRP antibody fremanezumab is successful in the prevention of chronic migraine. In preclinical rat experiments, fremanezumab has been shown to reduce calcitonin gene-related peptide (CGRP) release from trigeminal tissues and the aversive behaviour to noxious facial stimuli, which are characteristic pathophysiological changes accompanying severe primary headaches. To further decipher the effects of fremanezumab underlying these antinociceptive effects in rats, immunohistochemistry and ELISA techniques were used to analyse the content and concentration of CGRP in the trigeminal ganglion as well as the ratio of trigeminal ganglion neurons immunoreactive to CGRP and CGRP receptor components 1-10 days after subcutaneous injection of fremanezumab (30 mg/kg) compared to an isotype control antibody. After fremanezumab treatment, the fraction of trigeminal ganglion neurons immunoreactive to CGRP and the CGRP receptor components calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) was significantly lowered compared to the control. The content and concentration of CGRP in trigeminal ganglia were not significantly changed. A long-lasting reduction of CGRP receptors expressed in trigeminal afferents may contribute to the attenuation of CGRP signalling and antinociceptive effects of monoclonal anti-CGRP antibodies in rats.
ARTICLE | doi:10.20944/preprints201911.0131.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: epitope; monoclonal antibodies; open reading frame 3 protein; apoptosis; p53; porcine circovirus type 2; thimerosal; interfere; antibody binding; lymphocyte
Online: 12 November 2019 (16:20:27 CET)
Porcine circovirus type 2 (PCV2) is a small non-enveloped DNA virus that causes swine immunosuppression by inducing apoptosis in lymphocytes. The ORF3 protein plays a major role in PCV2-induced apoptosis in porcine kidney cells, but there is little information regarding this protein in PCV2-infected lymphocytes. In this study, hybridoma screening and epitope mapping were determined by using an indirect ELISA. The mAb 7D3 against ORF3 peptide (residues 35–65) of PCV2 were generated in this study. In vivo situation, the mAb 7D3 recognized ORF3 protein existed in PCV2-infected apoptotic porcine PBMCs. It is noteworthy that thimerosal interfered with the binding of mAb 7D3 to epitope and it was diminished by adding cysteine. Additionally, thimerosal interacting with cysteine-containing peptide was demonstrated by the PTI assay. Furthermore, thimerosal specifically interacted with the antigen-binding sites of mAb 7D3. This study suggested that thimerosal blockade the occlusion of the antigen-binding sites of mAb 7D3 to bind ORF3 peptide (residues 35–65) via thimerosal interacting with cysteine residues which should be located within the antigen-binding sites of mAb 7D3. Overall, the mAb 7D3 has been characterized and it will be a valuables tool in future studies of ORF3 function and the wider mechanism of cell apoptosis caused by PCV2 infection. Similarly, these techniques will be useful for applications in detecting thimerosal too.
ARTICLE | doi:10.20944/preprints202212.0189.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mouse CCR9, monoclonal antibody, epitope mapping, alanine scanning, enzyme-linked immunosorbent assay
Online: 12 December 2022 (03:54:29 CET)
C-C chemokine receptor 9 (CCR9) is a receptor for C-C-chemokine ligand 25 (CCL25). CCR9 is crucial in the chemotaxis of immune cells and inflammatory responses. Moreover, CCR9 is highly expressed in tumors including several solid tumors and T-cell acute lymphoblastic leukemia. Several preclinical studies have shown that anti-CCR9 monoclonal antibodies (mAbs) exert antitumor activity. Therefore, CCR9 is an attractive target for tumor therapy. In this study, we conducted the epitope mapping of an anti-mouse CCR9 (mCCR9) mAb, C9Mab-24 (rat IgG2a, kappa), using a 1 × alanine (1 × Ala) and 2 × alanine (2 × Ala)-substitution method via enzyme-linked immunosorbent assay. We first performed the 1 × Ala-substitution method using one alanine-substituted peptides of the mCCR9 N-terminus (amino acids 1-19). C9Mab-24 did not recognize two peptides (F14A and F17A), indicating that Phe14 and Phe17 are critical for C9Mab-24-binding to mCCR9. Furthermore, we conducted the 2 × Ala-substitution method using two consecutive alanine-substituted peptides of the mCCR9 N-terminus, and showed that C9Mab-24 did not react with four peptides (M13A–F14A, F14A–D15A, D16A–F17A, and F17A–S18A), indicating that 13-MFDDFS-18 is involved in C9Mab-24-binding to mCCR9. Overall, combining, the 1 × Ala or 2 × Ala scanning methods could be useful for understanding for target-antibody interaction.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Glioblastom; high-grade glioma; convection enhanced delivery; OS2966; CD29; β1 integrin; ITGB1; monoclonal antibody; clinical trial
Online: 2 December 2020 (09:11:37 CET)
Introduction: OS2966 is a fist-in-class, humanized and de-immunized monoclonal antibody which targets the adhesion receptor subunit, CD29/β1 integrin. CD29 expression is highly upregulated in glioblastoma and has been shown to drive tumor progression, invasion, and resistance to multiple modalities of therapy. Here, we present a novel Phase I clinical trial design addressing several factors plaguing effective treatment of high-grade gliomas (HGG). Study Design: This 2-part, ascending-dose, Phase I clinical trial will enroll patients with recurrent/progressive HGG requiring a clinically-indicated resection. In Study Part 1, patients will undergo stereotactic tumor biopsy followed by placement of a purpose-built catheter which will be used for intratumoral, convection-enhanced delivery (CED) of OS2966. Subsequently, patients will undergo their clinically-indicated tumor resection followed by CED of OS2966 to the surrounding tumor-infiltrated brain. Matched pre- and post-infusion tumor specimens will be utilized for biomarker development and validation of target engagement by receptor occupancy. Dose escalation will be achieved using a unique concentration-based accelerated titration design. Discussion: The present study design leverages multiple innovations including: 1) the latest CED technology, 2) 2-part design including neoadjuvant intratumoral administration, 3) a first-in-class investigational therapeutic, and 4) concentration-based dosing. Trial registration: A U.S. Food and Drug Administration (FDA) Investigational New Drug application (IND) for the above protocol is now active. A Phase I trial is registered at clinicialtrials.gov (NCT04608812).
ARTICLE | doi:10.20944/preprints201911.0023.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: monoclonal antibodies; Mabs; fusion; false positives; hapten immunoassays; competitive immunoassays; ELISA; antibody validation; antibody quality; microarray; hybridoma technology; linker recognition; high-throughput screening; HTS; heterology concept
Online: 3 November 2019 (17:00:59 CET)
The primary screening of hybridoma cells is a time-critical and laborious step during the development of monoclonal antibodies. Often critical errors occur in this phase, which supports the notion that the generation of monoclonal antibodies with hybridoma technology is difficult to control and hence a risky venture. We think that it is crucial to improve the screening process to eliminate most of the immanent deficits of the conventional approach. With this new microarray-based procedure, several advances could be achieved: Selectivity for excellent binders, high throughput, reproducible signals, avoidance of misleading avidity (multivalency) effects, and simultaneous performance of competition experiments. The latter can directly be used to select clones of desired cross-reactivity properties. In this paper, a model system with two excellent clones against carbamazepine, two weak clones and blank supernatant has been designed to examine the effectiveness of the new system. The excellent clones could be detected largely independent of the IgG concentration, which is unknown during the clone screening since the determination and subsequent adjustment of the antibody concentration is not possible in most cases. Furthermore, in this approach, the enrichment, isolation, and purification of IgG for characterization is not necessary. Raw cell culture supernatant can be used directly, even when fetal calf serum (FCS) or other complex media had been used. In addition, an improved method for the oriented antibody-immobilization on epoxy-silanized slides is presented. Based on the results of this model system, we conclude that this approach should be preferable to most other protocols leading to many of false positives, causing expensive and lengthy confirmation steps to weed out the poor clones.
ARTICLE | doi:10.20944/preprints202307.0169.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: HER2; breast cancer; monoclonal antibody; antitumor activities; mouse xenograft model; antibody-dependent cellular cytotoxicity
Online: 4 July 2023 (09:38:15 CEST)
Two monoclonal antibodies (mAbs) against human epidermal growth factor receptor 2 (HER2), trastuzumab and pertuzumab, were clinically approved. We previously developed a highly sensitive and specific anti-HER2 mAb, H2Mab-139 (mouse IgG1, kappa). In this study, we produced a defucosylated IgG2a version of anti‑HER2 mAb (H2Mab-139-mG2a-f) to enhance ADCC-mediated antitumor activity. H2Mab-139-mG2a-f exhibits a high binding affinity in flow cytometry with the dissociation constant (KD) determined to be 3.9 × 10‑9 M and 7.7 × 10‑9 M against HER2‑overexpressed Chinese hamster ovary (CHO)-K1 (CHO/HER2) and HER2-positive BT-474 cells, respectively. Moreover, we showed that H2Mab-139-mG2a-f exerted ADCC and complement-dependent cytotoxicity against CHO/HER2 and BT-474 cells in vitro and exhibited potent antitumor activities in the xenograft models. These results indicated that H2Mab-139-mG2a-f exerts antitumor effects against HER2-positive human breast cancers and could be useful for an antibody treatment regimen for HER2-positive human cancers.
ARTICLE | doi:10.20944/preprints201902.0117.v1
Online: 13 February 2019 (15:16:44 CET)
Tumor necrosis factor-α (TNFα), one of the major pro-inflammatory cytokines, plays a key role in an effective immune response. However, the chronic presence of TNFα can lead to several inflammatory disorders like rheumatoid arthritis, psoriasis, Crohn’s disease etc. Inhibition of TNFα by pharmacological inhibitors or antibodies has proven to be effective in palliative treatment to some extent. The aim of this study was to develop an anti-TNFα antibody which may be used as a therapeutic option to inhibit TNFα-mediated cytotoxicity. We characterized several hybridoma clones secreting monoclonal antibodies (mAbs) to human-TNFα. Four mAbs rescued L929 fibroblast cells from TNFα-triggered cell death and one of these, namely C8 was found to have the highest affinity. To gain insights into the mechanism by which mAb C8 inhibits human TNFα-mediated toxicity, the epitope corresponding to the mAb was delineated. The antigenic determinant was found to comprise of the stretch of amino acids 99-120, of which, 102-104 (QRE) form the core epitope. The observation was supported by bioinformatics analyses of an antigen-antibody complex model. In addition, the binding affinity of mAb C8 to TNFα was found to be comparable with that of Infliximab which is a commercially available anti TNFα mAb.
ARTICLE | doi:10.20944/preprints202301.0359.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: monoclonal antibodies; tixagevimab/cilgavimab; immunocompromised
Online: 19 January 2023 (12:00:57 CET)
Objectives: Monoclonal antibodies (mAbs) have proven to be a valuable tool against COVID-19, mostly among subjects with risk factors for progression to severe illness. Tixagevimab/cilgavimab (TIX/CIL), a combination of two Fc-modified human monoclonal antibodies, has been recently approved to be employed as early treatment. Methods: Two groups of immunocompromised patients exposed to different early treatments (i.e., TIX/CIL vs. other mAbs [casirivimab/imdevimab, bamlanivimab/etesevimab, sotrovimab]) were compared in terms of clinical outcomes (hospitalization and mortality within 14 days from administration) and time to the negativity of nasal swabs. We used either Pearson’s chi-square or Fisher’s exact test for categorical variables, whereas the Wilcoxon rank–sum test was employed for continuous ones. Kaplan–Meier curves were produced to compare the time to nasopharyngeal swab negativity. Results: Early treatment with TIX/CIL was administered to 19 immunocompromised patients, while 89 patients received other mAbs. Most of them were solid organ transplant recipients or suffering from hematologic or solid malignancies. Overall, no significant difference was observed between the two groups in terms of clinical outcomes. In the TIX/CIL group, one patient (1/19, 5.3%), who was admitted to the emergency room within the first 14 days from treatment and was hospitalised due to COVID-19 progression, died. Regarding the time to nasal swab negativity, no significant difference (p=0.088) emerged. Conclusions: Early treatment of SARS-CoV-2 infection with TIX/CIL shows favourable outcomes in a small group of immunocompromised patients, reporting no significant difference when compared to similar patients treated with other mAbs.
COMMUNICATION | doi:10.20944/preprints202308.0725.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: dPD-L1; monoclonal antibody; peptide immunization; immunohistochemistry
Online: 9 August 2023 (07:11:56 CEST)
Immune checkpoint blockade therapy has shown successful clinical outcomes in multiple human cancers. In dogs, several types of tumors resemble human tumors in many respects. Therefore, several groups have developed the anti-dog programmed cell death ligand 1 (dPD-L1) monoclonal antibodies (mAbs) and showed efficacy in several canine tumors. To examine the abundance of dPD-L1 in canine tumors, anti-dPD-L1 diagnostic mAbs for immunohistochemistry are required. In this study, we immunized the peptide in the dPD-L1 intracellular domain, and established anti-dPD-L1 mAbs, L1Mab-352 (mouse IgG1, kappa) and L1Mab-354 (mouse IgG1, kappa). In enzyme-linked immunosorbent assay, L1Mab-352 and L1Mab-354 showed high binding affinity to the dPD-L1 peptide, and the dissociation constants (KD) were determined as 6.9 ×10-10 M and 7.2 ×10-10 M, respectively. Furthermore, L1Mab-352 and L1Mab-354 were applicable for the detection of dPD-L1 in immunohistochemical analysis in paraffin-embedded dPD-L1-expressed cells. These results indicated that L1Mab-352 and L1Mab-354 are useful for detecting dPD-L1 in immunohistochemical analysis.
ARTICLE | doi:10.20944/preprints202212.0218.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Monoclonal antibodies; Variable dosing; Fixed dosing; Oncology
Online: 13 December 2022 (02:25:03 CET)
Oncological patients need the proper doses of medications to facilitate their recovery. The two basic approaches used in dosing Monoclonal Antibodies (mAbs) are fixed-dose combination and variable dosing. In Fixed-Dose Combination Drugs (FDCs), two or more active components are combined in a single formulation at a predetermined dose. Variable dosage, which has long been the industry standard, is the polar opposite of this approach. The body changes over time; the Body Surface Area (BSA) in square meters is often used as a Measure (m2). This study uses a systematic review. Most mAbs used in oncology are predominantly given as cytotoxic anticancer drugs using body-size-based (variable) regimens. Despite the benefits of fixed-dose, variable dosing has become the industry standard, despite being criticized for ineffectiveness. While variable dosing has some advantages, the prevalent view is that continuous dosing has significant advantages based on the balance of probabilities. After assessing each alternative, including its benefits and drawbacks, history of use, and suitability in the current context, fixed dosing emerges as a viable option.
ARTICLE | doi:10.20944/preprints202104.0619.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: monoclonal antibodies; ARDS; cytokine storm syndrome; inflammation
Online: 22 April 2021 (20:58:22 CEST)
Background: Cytokine storm in COVID-19 is heterogenous. There are at least three subtypes: cytokine release syndrome (CRS), macrophage activation syndrome (MAS), and sepsis. Methods: A retrospective study comprising 276 patients with SARS-CoV-2 pneumonia. All patients were tested for ferritin, interleukin-6, D-Dimer, fibrinogen, calcitonin, and C-reactive protein. According to the diagnostic criteria, three groups of patients with different subtypes of cytokine storm syndrome were identified: MAS, CRS or sepsis. In each group, treatment results were assessed depending on whether or not tocilizumab was used. Results: MAS was diagnosed in 9.1% of the patients examined, CRS in 81.8%, and sepsis in 9.1%. Median serum ferritin in patients with MAS was significantly higher (5894 vs. 984 vs. 957 ng/ml, p <0.001) than in those with CRS or sepsis. Hypofibrinogenemia and pancytopenia were also observed in MAS patients. In CRS patients, a higher mortality rate was observed among those who received tocilizumab, 21 vs. 10 patients (p=0.043), RR = 2.1 (95% CI 1.0-4.3). In MAS patients, tocilizumab decreased the mortality, 13 vs. 6 patients (p=0.013), RR = 0.50 (95% CI 0.25-0.99). Сonclusions: Tocilizumab therapy in patients with COVID-19 and CRS was associated with increased mortality, while in MAS patients it contributed to reduced mortality.
ARTICLE | doi:10.20944/preprints202207.0223.v1
Subject: Biology And Life Sciences, Virology Keywords: Monoclonal antibodies; Sotrovimab; COVID-19; Omicron; BA.2
Online: 14 July 2022 (12:22:21 CEST)
Coronavirus disease 19 (COVID-19) continues to spread worldwide as a severe pandemic. The Omicron BA.2 became the predominant variant and the protagonist of the ongoing surge. As the virus continues to mutate, using of approved drugs or developing new therapeutic or prophylactic therapies against COVID-19 could be more complex. Sotrovimab is a monoclonal antibody (mAb) targeting the conserved epitope on the spike protein receptor; the most recent studies observed that it has substantially decreased in vitro activity against the Omicron BA.2 subvariant, but real-life data are still scarce. We describe the outcome of a case series of outpatients with BA.1 or BA.2 infection treated with sotrovimab. We conducted a retrospective observational study including all non-hospitalized adult patients treated with sotrovimab, for which a Sanger sequencing of SARS-CoV-2 was performed within a regional genomic surveillance program. Eleven (50%) patients with BA.1 infection and eleven (50%) with BA.2 infection were considered. Most patients were immunocompromised. During the follow-up period, no patient died and only one with BA.1 infection was hospitalized for severe COVID-19 pneumonia onset. One month after treatment, 90.9% of patients were completely asymptomatic in each group. We demonstrated that patients carrying the BA.2 variant treated with sotrovimab did not evolve to severe COVID-19, showing a similar outcome to BA.1 infected patients. Further studies are needed to prove that vaccination or the presumably high doses of mAbs used can protect this group of patients at high risk of progression.
ARTICLE | doi:10.20944/preprints201811.0383.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ADCC; glycosylation; kifunensine; plant made pharmaceuticals; monoclonal antibody
Online: 16 November 2018 (07:24:35 CET)
N-glycosylation has been shown to affect the pharmacokinetic properties of several classes of biologics including monoclonal antibodies, blood factors, and lysosomal enzymes. In the last two decades, N-glycan engineering has been employed to achieve a N-glycosylation profile that is either more consistent or aligned with a specific improved activity (i.e. effector function or serum half-life). In particular, attention has focused on engineering processes in vivo or in vitro to alter the structure of the N-glycosylation of the Fc region of anti-cancer monoclonal antibodies in order to increase antibody-dependent cell-mediated cytotoxicity (ADCC). Here we applied the mannosidase I inhibitor kifunensine to the Nicotiana benthamiana transient expression platform to produce an afucosylated anti-CD20 antibody (rituximab). We determined the optimal concentration of kifunensine used in the infiltration solution, 0.375 µM, which was sufficient to produce exclusively oligomannose glycoforms, at a concentration 14 times lower than previously published levels. The resulting afucosylated rituximab revealed a 14-fold increase in ADCC activity targeting the lymphoma cell line Wil2-S when compared with rituximab produced in the absence of kifunensine. When applied to the cost-effective and scalable N. benthamiana transient expression platform, the use of kifunensine allows simple in-process glycan engineering without the need for transgenic hosts.
ARTICLE | doi:10.20944/preprints201811.0052.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: analytical electrophoresis; IgG subclasses; monoclonal IgG; protein charge
Online: 2 November 2018 (10:42:20 CET)
It has been known since the 1930’s that all immunoglobulins carry a weak negative charge in physiological solvents. However, there has been no systematic exploration of this fundamental property. Accurate charge measurements have been made using membrane confined electrophoresis in two solvents (pH 5.0 and pH 7.4) on a panel of twelve mAb IgGs, as well as their F(ab’)2 and Fc fragments. The following observations were made at pH 5.0: 1) the measured charge differs from the calculated charge by ~40 for the intact IgGs, and by ~20 for the Fcs; 2) the intact IgG charge depends on both Fv and Fc sequences, but does not equal the sum of the F(ab)’2 and Fc charge; 3) the Fc charge is consistent within a class. In phosphate buffered saline, pH 7.4: 1) the intact IgG charges ranged from 0 to -13; 2) the F(ab’)2 fragments are nearly neutral for IgG1s and IgG2s, and about -5 for some of the IgG4s; 3) all Fc fragments are weakly anionic, with IgG1 < IgG2 < IgG4; 4) the charge on the intact IgGs does not equal the sum of the F(ab’)2 and Fc charge. In no case is the calculated charge, based on H+ binding, remotely close to the measured charge. The charge on IgGs in physiological solvent is sufficiently small to minimize its contribution to thermodynamic nonideality. Some of the mAbs carried a charge in physiological salt that was outside the range observed for serum-purified human poly IgG. To best match physiological properties, a therapeutic mAb should have a measured charge that falls within the range observed for serum-derived human IgGs.
ARTICLE | doi:10.20944/preprints202310.0185.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: monoclonal antibodies; myasthenia gravis; bioinformatics; mechanism of action; IMGT
Online: 4 October 2023 (03:54:47 CEST)
Background: Myasthenia Gravis (MG) is a rare autoimmune disease presenting with au-to-antibodies that affect the neuromuscular junction. Aside from symptomatic treatment options, novel therapeutics include monoclonal antibodies (mAbs). IMGT®, the international ImMunoGe-neTics information system® (https://www.imgt.org), extends the characterization of therapeutic antibodies with a systematic description of their mechanisms of action (MOA) and makes them available through its database for mAbs and fusion proteins, IMGT/mAb-DB. Methods: Using the available literature data combined with the amino acid sequence analyses from mAbs managed in IMGT/2Dstructure-DB, the IMGT® protein database, biocuration allowed to define in a standardized way descriptions of MOA of mAbs that target molecules towards MG treatment. Results: New therapeutic targets include FcRn and molecules such as CD38, CD40, CD19, MS4A1 and interleukin-6 receptor. A standardized graphical representation of the MOA of selected mAbs was created and integrated within IMGT/mAb-DB. The main mechanisms involved in these mAbs are either blocking or neutralizing. Therapies directed to B cell depletion and plasma cells have a blocking MOA with an immunosuppressant effect along with Fc-effector function (MS4A1, CD38) or FcγRIIb engager effect (CD19). Monoclonal antibodies targeting the complement also have blocking MOA with a complement inhibitor effect and treatments targeting T cells have a blocking MOA with an immunosuppressant effect (CD40) and Fc-effector function (IL6R). On the other hand, FcRn antagonists present a neutralizing MOA with an FcRn inhibitor effect. Conclusion: The MOA of each new mAb needs to be considered in association with the immuno-pathogenesis of each of the subtypes of MG in order to integrate the new mAbs as a viable and safe option in the therapy decision process. In IMGT/mAb-DB, mAbs for MG are characterized by their sequence, domains, chains and their MOA is described.
REVIEW | doi:10.20944/preprints202309.0943.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: arbovirus; monoclonal antibody; flavivirus; alphavirus; neutralizing antibody; antibody discovery
Online: 14 September 2023 (03:51:07 CEST)
Antibody-based passive immunotherapy has been used effectively in the therapy and prophylaxis of infectious diseases. Outbreaks of the emerging viral infections from arthropod-borne viruses (arboviruses) represent a global public health problem due to the rapid spread and urge actions and treatment of the infected individuals to combat them. Preparedness in advance developing antivirals and studies related to the epidemiology could protect us from damages and losses. Immunotherapy based on monoclonal antibodies (mAbs) has shown to be very specific to combat infectious diseases and several illnesses. Recent advances in the mAb discovery techniques allowed the development and approval of a wide number of therapeutic mAbs. This review focuses on the technological approaches available to select neutralizing mAbs for emerging arbovirus infections and outstanding strategies to obtain highly effective and potent mAbs. The characteristics of mAbs developed as prophylactic and therapeutic antiviral agents for the dengue, Zika, chikungunya and West Nile virus are presented, as well as the protective effect verified in animal model studies.
REVIEW | doi:10.20944/preprints202306.0742.v1
Subject: Medicine And Pharmacology, Hematology Keywords: Cryoglobulinaemia; IgM; Waldenström macroglobulinemia; monoclonal gammopathy of clinical significance
Online: 12 June 2023 (03:16:55 CEST)
Cryoglobulinaemia is characterised by immunoglobulins which precipitate at temperatures be-low 37°C and redissolve on warming. Monoclonal IgM immunoglobulin may be associated with type I and II cryoglobulinaemia with underlying Waldenström macroglobulinemia, monoclonal gammopathy of undetermined significance or other non-Hodgkin lymphoma. We review the clinical characteristics, laboratory testing and suggest a management approach for monoclonal IgM associated cryoglobulinaemia. Laboratory testing is critical as even a minimal amount of measurable cryoglobulin may result in symptoms. Accurate detection of cryoglobulins may be challenging and care must be taken with preanalytical variables and repeat testing of monoclo-nal protein and cryoglobulins is indicated if clinical suspicion is high. Presentations range from asymptomatic disease to multisystem involvement so careful evaluation of the features and thorough interrogation of organ systems and the underlying clone is critical. Immediate man-agement is required for clinical red flag features. Due to their rarity, data to inform treatment decisions are scant and collaborative research is imperative to aid defining optimal treatment strategies.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: COVID-19; SARS-CoV-2; vaccine; coronavirus; monoclonal antibodies
Online: 3 December 2020 (09:20:35 CET)
Knowing the “point of view” of the immune system is essential to understand the characteristic of a pandemic, such as that generated by the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2, responsible for the Coronavirus Disease (COVID)-19. In this review, we will discuss the general host/pathogen interactions dictating protective immune response or immunopathology, addressing the role of immunity or immunopathology in influencing the clinical infection outcome, and debate the potential immunoprophylactic and immunotherapy strategies required to fight the virus infection.
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: chronic-ataxic neuropathy; anti-disialosyl; IgM monoclonal gammopathy; CANOMAD
Online: 5 October 2020 (11:07:50 CEST)
Objective: Elucidate the main clinical aspects of the CANOMAD spectrum. Methods: Bibliographical review trough databases (PubMed, Google Scholar, Orphanet, Oxford Academic) of articles from 1985 (1) to 2019 and later selection of the most applicable of the above, in order to construct a non-systematic review. Conclusion: CANOMAD is a chronic-ataxic autoimmune neuropathy associated with IgM monoclonal gammopathy. The correct diagnosis of this rare and multi-faceted disease will help optimal treatment.
REVIEW | doi:10.20944/preprints202309.1136.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Immunotherapy; autoimmune diseases; monoclonal antibodies; bispecific antibodies; CAR-T cells
Online: 18 September 2023 (07:17:18 CEST)
Systemic autoimmune diseases (SAIDs) such as systemic lupus erythematosus (SLE), systemic sclerosis (SSc) and rheumatoid arthritis (RA) are fully related to the unregulated innate and adaptive immune systems involved in their pathogenesis. They have similar pathogenic characteristics including the interferon signature, loss of tolerance to self-nuclear antigens, and enhanced tissue damage like necrosis and fibrosis. Glucocorticoids and immunosuppressants, which have limited specificity and are prone to tolerance, are used as the first-line therapy. A plethora of novel immunotherapies have been developed including monoclonal and bispecific antibodies, and other biological agents to target cellular and soluble factors involved in disease pathogenesis such as B cells, co-stimulatory molecules, cytokines or their receptors, and signalling molecules. Many of these have shown encouraging results in clinical trials. CAR-T cell therapy is considered the most promising technique for curing autoimmune diseases, with recent successes in the treatment of SLE and SSc.
COMMUNICATION | doi:10.20944/preprints202307.0721.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: mouse HER2; monoclonal antibody; cell-based Immunization and screening; CBIS
Online: 12 July 2023 (03:20:12 CEST)
Overexpression of human epidermal growth factor receptor 2 (HER2) in breast cancer is an important target of monoclonal antibody (mAb) therapy such as trastuzumab. Due to the development of trastuzumab-deruxtecan, an antibody-drug conjugate, the targetable HER2-positive breast cancer patients have been expanded. To evaluate developing modalities using anti-HER2 mAbs, reliable preclinical mouse models are required. Therefore, sensitive mAbs against mouse HER2 (mHER2) should be established. This study developed mHER2 mAbs using the Cell-Based Immunization and Screening (CBIS) method. The established anti-mHER2 mAbs, H2Mab-300 (rat IgG2b, kappa) and H2Mab-304 (rat IgG1, kappa), reacted with mHER2-overexpressed Chinese hamster ovary-K1 (CHO/mHER2) and endogenously mHER2-expressed cell line, NMuMG (a mouse mammary gland epithelial cell) by flow cytometry. Furthermore, these mAbs never recognized mHER2-knockout NMuMG cells. The kinetic analysis using flow cytometry indicated that the dissociation constant (KD) of H2Mab-300 and H2Mab-304 for CHO/mHER2 was 1.2 × 10−9 M and 1.7 × 10−9 M, respectively. The KD of H2Mab-300 and H2Mab-304 for NMuMG was 4.9 × 10−10 M and 9.0 × 10−10 M, respectively. These results indicated that H2Mab-300 and H2Mab-304 could apply to the detection of mHER2 using flow cytometry and may be useful to obtain the proof of concept in preclinical studies.
COMMUNICATION | doi:10.20944/preprints202305.0641.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: mouse EGFR; monoclonal antibody; Cell-Based Immunization and Screening; CBIS
Online: 9 May 2023 (10:42:31 CEST)
The Epidermal Growth Factor Receptor (EGFR) overexpression or its mutation mediates the sustaining proliferative signaling in cancers. Human EGFR-targeting monoclonal antibody (mAb) therapy such as cetuximab has been approved for clinical use in patients with colorectal cancers and head and neck squamous cell carcinomas. A reliable preclinical mouse model is essential to further develop the mAb therapy against EGFR. However, a mAb against mouse EGFR (mEGFR) for flow cytometry has not been established. In this study, we developed a specific and sensitive mAb for mEGFR using the Cell-Based Immunization and Screening (CBIS) method. The established anti-mEGFR mAb, EMab-300 (rat IgG1, kappa) reacted with mEGFR-overexpressed Chinese hamster ovary-K1 (CHO/mEGFR) and endogenously mEGFR-expressed cell lines, including NMuMG (a mouse mammary gland epithelial cell) and Lewis lung carcinoma cells by flow cytometry. The kinetic analysis using flow cytometry indicated that the dissociation constant (KD) of EMab-300 for CHO/mEGFR and NMuMG was 4.3 × 10−8 M and 1.9 × 10−8 M, respectively. These results indicated that EMab-300 applies to the detection of mEGFR by flow cytometry, and is expected in the use of preclinical study.
ARTICLE | doi:10.20944/preprints202211.0071.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: mouse CCR3; monoclonal antibody; epitope mapping; alanine scanning; flow cytometry
Online: 3 November 2022 (07:35:45 CET)
The CC chemokine receptor 3 (CCR3) is a receptor for CC chemokines, including CCL5/RANTES, CCL7/MCP-3, and CCL11/eotaxin. CCR3 is expressed on the surface of eosinophils, basophils, a subset of Th2 lymphocytes, mast cells, and airway epithelial cells. CCR3 and its ligands are involved in airway hyperresponsiveness in allergic asthma, ocular allergy, and cancers. Therefore, CCR3 is an attractive target for those therapies. Previously, anti-mouse CCR3 (mCCR3) monoclonal antibodies (mAbs), C3Mab-3 (rat IgG2a, kappa), and C3Mab-4 (rat IgG2a, kappa) were developed using the Cell-Based Immunization and Screening (CBIS) method. In this study, the binding epitope of these mAbs was investigated using flow cytometry. The CCR3 extracellular domain-substituted mutant analysis showed that C3Mab-3, C3Mab-4, and a commercially available mAb (J073E5) recognized the N-terminal region (amino acids 1–38) of mCCR3. Next, the alanine scanning was conducted in the N-terminal region. The results revealed that Ala2, Phe3, Asn4, and Thr5 of mCCR3 are involved in C3Mab-3 binding, whereas Ala2, Phe3, and Thr5 are essential to C3Mab-4 binding, and Ala2 and Phe3 are crucial to J073E5 binding. These results reveal the involvement of the N-terminus of mCCR3 in the recognition of C3Mab-3, C3Mab-4, and J073E5.
ARTICLE | doi:10.20944/preprints202203.0155.v1
Subject: Biology And Life Sciences, Virology Keywords: SARS-CoV-2; Omicron variant; Monoclonal antibody; Neutralization; Spike protein
Online: 10 March 2022 (14:30:25 CET)
SARS-CoV-2 Omicron variants contain many mutations in its spike receptor binding domain, the target of all authorized monoclonal antibodies (mAbs). Determining the extent to which Omicron variants reduced mAb susceptibility is critical to preventing and treating COVID-19. We systematically reviewed PubMed and three preprint servers, last updated February 22, 2022, of the in vitro activity of authorized mAbs against the Omicron variants. Thirty-three studies were eligible including 33 containing Omicron BA.1 susceptibility data and five that also contained Omicron BA.2 susceptibility data. The first two authorized mAb combinations, bamlanivimab/etesevimab and casirivimab/imdevimab, were inactive against the Omicron BA.1 and BA.2 variants. In 24 studies, sotrovimab (third authorized mAb) displayed a median 4.1-fold (IQR: 2.4-7.6) reduced activity against Omicron BA.1 and, in four studies, a median 26-fold (IQR:16-35) reduced activity against Omicron BA.2. In 18 studies, cilgavimab and tixagevimab independently displayed median reductions in activity of >300-fold against Omicron BA.1, while in ten studies, the cilgavimab/tixagevimab combination (fourth authorized mAb preparation) displayed a median 63-fold (IQR: 26-145) reduced activity against Omicron BA.1. In two studies, cilgavimab was approximately 100-fold more susceptible to BA.2 than to BA.1. In two studies, bebtelovimab, the most recently authorized mAb, was fully active against both the Omicron variants. Disparate results between assays were common as evidenced by a median 42-fold range (IQR: 25-625) in IC50 between assays for the eight authorized individual mAbs and three authorized mAb combinations. Highly disparate results between published assays indicates a need for improved mAb susceptibility test standardization or inter-assay calibration.
COMMUNICATION | doi:10.20944/preprints202304.0032.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: mouse CD39; monoclonal antibody; the Cell-Based Immunization and Screening; CBIS
Online: 4 April 2023 (02:29:25 CEST)
CD39 is involved in adenosine metabolism through conversion of extracellular ATP to adenosine. Because extracellular adenosine plays a critical role in the immune suppression of tumor microenvironment, the inhibition of CD39 activity by monoclonal antibodies (mAbs) is one of the important strategies for tumor therapy. In this study, we developed specific and sensitive mAbs for mouse CD39 (mCD39) using the Cell-Based Immunization and Screening (CBIS) method. The established anti-mCD39 mAbs, which were established by the CBIS method including C39Mab-1 (rat IgG2a, kappa) and C39Mab-2 (rat IgG2a, lambda), reacted with not only mCD39-overexpressed Chinese hamster ovary-K1 (CHO/mCD39) but also endogenously mCD39-expressed cell lines, such as L1210 (mouse lymphocytic leukemia) and J774-1 (mouse macrophage-like) cell lines through flow cytometry. Kinetic analyses using flow cytometry indicated that the dissociation constant (KD) of C39Mab-1 and C39Mab-2 for CHO/mCD39 was 7.3 × 10−9 M and 5.5 × 10−9 M, respectively. KD of C39Mab-1 and C39Mab-2 for L1210 was 3.3 × 10−9 M and 3.6 × 10−10 M, respectively. Furthermore, C39Mab-1 could detect the lysate of CHO/mCD39 by western blot analysis. These results indicate that C39Mab-1 and C39Mab-2 are useful for the detection of mCD39 in many functional studies.
ARTICLE | doi:10.20944/preprints202102.0075.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: bat; monoclonal antibodies; lyssaviruses; neutralization; glycoprotein; ABLV; rabies; RABV; phage display
Online: 2 February 2021 (08:27:58 CET)
Australian bat lyssavirus (ABLV) is a rhabdovirus that circulates in four species of pteropid bats (ABLVp) and the yellow-bellied sheath-tailed bat (ABLVs) in mainland Australia. In the three confirmed human cases of ABLV, rabies illness preceded fatality. As with rabies virus (RABV), post-exposure prophylaxis (PEP) for potential ABLV infections consists of wound cleansing, ad-ministration of the rabies vaccine and injection of rabies immunoglobulin (RIG) proximal to the wound. Despite the efficacy of PEP, the inaccessibility of human RIG (HRIG) in the developing world and the high immunogenicity of equine RIG (ERIG) has led to consideration of human monoclonal antibodies (hmAbs) as a passive immunization option that offers enhanced safety and specificity. Using a recombinant vesicular stomatitis virus (rVSV) expressing the glycoprotein (G) protein of ABLVs and phage display, we identified two hmAbs, A6 and F11, which completely neutralize ABLVs/ABLVp, and RABV at concentrations ranging from 0.19-3.12 µg/mL and 0.39-6.25 µg/mL respectively. A6 and F11 recognize overlapping epitopes in the lyssavirus G protein, ef-fectively neutralizing phylogroup 1 lyssaviruses, while having little effect on phylogroup 2 and non-grouped diverse lyssaviruses. These results suggest A6 and F11 could be effective therapeutic and diagnostic tools for phylogroup 1 lyssavirus infections.
REVIEW | doi:10.20944/preprints202308.0567.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: Pancreatic Ductal Adenocarcinoma; secretome; cell signaling; tumor microenvironment; small molecules; monoclonal antibodies.
Online: 7 August 2023 (12:12:00 CEST)
Pancreatic ductal adenocarcinoma (PDAC) is a ravaging disease whose poor prognosis requires a more detailed understanding of its biology to foster the development of effective therapies. The unsatisfactory results of treatments targeting cell proliferation and its related mechanisms suggested to rather focus on the inflammatory tumor microenvironment (TME). Here, we discuss the role of cancer secreted proteins in the complex TME tumor-stroma crosstalk, to sched lights on druggable molecular targets for the development of innovative, safer and more efficient therapeutic strategies.
REVIEW | doi:10.20944/preprints202303.0072.v1
Subject: Engineering, Bioengineering Keywords: glycosylation, glycoengineering, biologic, therapeutic protein, gene therapy, cell-based therapy, monoclonal antibody
Online: 3 March 2023 (10:43:51 CET)
Over recent decades, therapeutic proteins have had widespread success in treating a myriad of diseases. Glycosylation, a near universal feature of this class of drugs, is a critical quality attribute that significantly influences the physical properties, safety profile and biological activity of therapeutic proteins. Optimizing protein glycosylation, therefore, offers an important avenue to developing more efficacious therapies. In this review, we discuss specific examples of how variations in glycan structure and glycoengineering impacts the stability, safety, and clinical efficacy of protein-based drugs that are already in the market as well as those that are still in preclinical development. We also highlight the impact of glycosylation on next generation biologics such as T cell-based cancer therapy and gene therapy.
ARTICLE | doi:10.20944/preprints202105.0302.v2
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: immune checkpoint; HVEM; BTLA; monoclonal antibody; cancer immunotherapy; humanized mice; prostate cancer
Online: 9 June 2021 (11:26:57 CEST)
The Herpes Virus Entry Mediator (HVEM) delivers a negative signal to T cells mainly through the B and T Lymphocyte Attenuator (BTLA) molecule and thus, could represent a novel immune checkpoint during an anti-tumor immune response. A formal demonstration that HVEM can be targeted for cancer immunotherapy is however still lacking. Here, we first show that HVEM and BTLA were associated to a worse prognosis in patients with prostate adenocarcinomas, indicating a detrimental role for this pair of molecule during prostate cancer progression. We then show that a monoclonal antibody to human HVEM significantly impacted the growth of a prostate cancer cell line in immuno-compromised NOD.SCID.gc-null mice reconstituted with human T cells. Using CRISPR/Cas9, we showed that HVEM expression by the tumor was mandatory to observe the therapeutic effect. Mechanistically, tumor control was dependent on CD8+ T cells and was associated to an increase in the proliferation and number of tumor-infiltrating leukocytes. Accordingly, the expression of genes belonging to various T cell activation pathways were enriched in tumor infiltrating leukocytes, whereas genes associated with immuno-suppressive pathways were decreased, possibly resulting in modifications of leukocyte adhesion and motility. Finally, we developed a simple in vivo assay in humanized mice to directly demonstrate that HVEM was an immune checkpoint for T-cell mediated tumor control. Our results show that targeting HVEM is a promising strategy for prostate cancer immunotherapy.
ARTICLE | doi:10.20944/preprints202305.1339.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Multiple myeloma; monoclonal gammopathy of undetermined significance; serum diagnostic metabolites; Nuclear Magnetic Resonance
Online: 18 May 2023 (11:02:34 CEST)
Multiple myeloma (MM) is an incurable hematological cancer. It is preceded by monoclonal gammopathy of uncertain significance (MGUS), an asymptomatic phase. It has been demonstrated that early detection increases the 5-year survival rate. However, blood-based biomarkers that enable early disease detection are lacking. Metabolomic and lipoprotein subfraction variable profiling is gaining traction to expand our understanding of disease states and, more specifically, for identifying diagnostic markers in patients with hematological cancers. This study aims to enhance our understanding of multiple myeloma (MM) and identify candidate metabolites, allowing for more effective preventative treatment. Serum was collected from 25 healthy controls, 20 patients with MGUS, and 30 patients with MM. 1H-NMR (nuclear magnetic resonance) spectroscopy was utilized to evaluate serum samples. The metabolite concentrations were examined using multivariate, univariate, and pathway analysis. Metabolic profiles of the MGUS patients revealed lower levels of alanine (F.C. = 0.8, p = 0.002), lysine (FC = 0.8, p < 0.001), leucine (FC=0.7, p < 0.001) but higher levels of formic acid (FC=1.6, p ≤ 0.001) when compared to controls. However, metabolic profiling of MM patients compared to controls exhibited decreased levels of total Apolipoprotein-A1 (FC =0.6, p<0.001), HDL-4 Apolipoprotein-A1 (FC = 0.5, p ≤ 0.001), HDL-4 Apolipoprotein-A2 (FC = 0.6, p < 0.001), HDL Free Cholesterol (FC = 0.7, p < 0.001), HDL-3 Cholesterol (FC = 0.5, p ≤ 0.001) and HDL-4 Cholesterol (FC = 0.5, p ≤ 0.001). Lastly, metabolic comparison between MGUS to MM patients primarily indicated alterations in lipoproteins levels: Total Cholesterol (FC = 0.6, p ≤ 0.001), HDL Cholesterol (FC = 0.7, p ≤ 0.001), HDL Free Cholesterol (FC = 0.4, p ≤ 0.001), Total Apolipoprotein-A1 (FC = 0.7, p ≤ 0.001), HDL Apolipoprotein-A1 (FC = 0.7, p ≤ 0.001), HDL-4 Apolipoprotein-A1 (FC = 0.6, p ≤ 0.001) and HDL-4 Phospholipids (FC = 0.6, p ≤ 0.001). This study provides novel insights into the serum metabolic and lipoprotein subfraction changes in patients as they progress from a healthy state to MGUS to MM, which may allow for earlier clinical detection and treatment.
BRIEF REPORT | doi:10.20944/preprints202305.0688.v2
Subject: Public Health And Healthcare, Public Health And Health Services Keywords: hypertonic salt solution; impregnation; filtering face piece; human monoclonal antibody; dry blood spot
Online: 17 May 2023 (04:33:54 CEST)
There is little doubt that final victories over pandemics, such as COVID-19, are attributed to herd immunity, either through post-disease convalescence or active immunization of a high percentage of the world's population with vaccines, demonstrating protection from infection and transmission, being available in large quantities and at reasonable prices. However, it is assumable that humans with immune defects or immune suppression, e.g., as a consequence of allograft transplantation, cannot be immunized actively nor produce sufficient immune responses to prevent SARS-CoV-2 infections. These subjects desperately need other strategies, such as sophisticated protection measures and active immunization. Hypertonic salt solutions attack vulnerable core areas of viruses, i.e., salt denatures surface proteins and thus prohibits virus penetration of somatic cells. It has to be ensured that somatic proteins are not affected by denaturation regarding this unspecific virus protection. Impregnating filtering facepieces with hypertonic salt solutions is a straightforward way to inactivate viruses and other potential pathogens. As a result of the contact of salt crystals on the filtering facepiece, these pathogens become denatured and inactivated almost quantitatively. Such a strategy could be easily applied to fight against the COVID-19 pandemic and other ones that may occur in the future. Another possible tool to fight the COVID-19 pandemic is passive immunization with antibodies against SARS-CoV-2, preferably from human origin. Such antibodies can be harvested from patients´ human sera, which have successfully survived their SARS-CoV-2 infection. The disadvantage of a rapid decrease of the immunoglobulin titer after infection ends can be overcome by immortalizing antibody-producing B-cells via fusion with, e.g., mouse myeloma cells. The resulting monoclonal antibodies are then of human origin and available in, at least theoretically, unlimited amounts. Finally, dry blood spots are a valuable tool for surveilling the population´s immunity.
REVIEW | doi:10.20944/preprints202201.0280.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: podoplanin, PDPN, tumor malignancy, tumor marker, antibody therapy, cancer-specific monoclonal antibody, CasMab
Online: 19 January 2022 (16:05:50 CET)
Podoplanin (PDPN) is a cell-surface mucin-like glycoprotein that plays a critical role in tumor development and normal development of the lung, kidney, and lymphatic vascular systems. PDPN is overexpressed in several tumors and is involved in their malignancy. PDPN induces platelet aggregation through binding to platelet receptor C-type lectin-like receptor 2. Furthermore, PDPN modulates signal transductions that regulate cell proliferation, differentiation, migration, invasion, epithelial to mesenchymal transition, and stemness, all of which are crucial for the malignant progression of tumor. In the tumor microenvironment (TME), PDPN expression is up-regulated in the tumor stroma, including cancer-associated fibroblasts (CAFs) and immune cells. CAFs play significant roles in the extracellular matrix remodeling and the development of immunosuppressive TME. Additionally, PDPN functions as a co-inhibitory molecule on T cells, indicating the involvement with immune evasion. In this review, we describe the mechanistic basis and diverse roles of PDPN in malignant progression of tumor and discuss the possibility of the clinical application of PDPN-targeted cancer therapy, including cancer-specific monoclonal antibodies, and chimeric antigen receptor T technologies.
ARTICLE | doi:10.20944/preprints202008.0643.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: ulcerative colitis; inflammatory bowel disease; immunotherapy; Bin1 monoclonal antibody; enteric neurons; microbiome; colon
Online: 28 August 2020 (11:45:28 CEST)
Ulcerative colitis (UC) is a common chronic disease of the large intestine. Current anti-inflammatory drugs prescribed to treat this disease have limited utility due to significant side-effects. Thus, immunotherapies for UC treatment are still sought. In the DSS mouse model of UC, we recently demonstrated that systemic administration of the Bin1 monoclonal antibody 99D (Bin1 mAb) developed in our laboratory was sufficient to reinforce intestinal barrier function and preserve an intact colonic mucosa, compared to control subjects which displayed severe mucosal lesions, high-level neutrophil and lymphocyte infiltration of mucosal and submucosal areas, and loss of crypts. Here we report effects of Bin1 mAb on colonic neurons and the gut microbiome that correlate with the benefits of treatment. In the DSS model, we found that induction of UC was associated with disintegration of enteric neurons and elevated levels of glial cells, which translocated to the muscularis at distinct sites. Further, we characterized an altered gut microbiome in DSS treated mice associated with pathogenic proinflammatory characters. Both of these features of UC induction were normalized by Bin1 mAb treatment. With regard to microbiome changes, we observed in particular that Firmicutes were eliminated by UC induction and that Bin1 mAb treatment restored this phylum including the genus Lactobacillus and Akkermansia as beneficial microorganisms. Overall, our findings suggest that the intestinal barrier function restored by Bin1 immunotherapy in the DSS model of UC is associated with a preservation of enteric neurons and an improvement in the gut microbiome, contributing overall to a healthy intestinal tract.
ARTICLE | doi:10.20944/preprints201805.0456.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: monoclonal antibody; immunoglobulin G; glycosylation; Chinese hamster ovary; perfusion cell culture; continuous biomanufacturing
Online: 30 May 2018 (16:52:12 CEST)
A critical quality attribute of therapeutic monoclonal antibodies (mAbs) is the terminal sugar molecules of the N-linked glycan attached to the fragment crystalizable (Fc) region. There exists naturally-occurring heterogeneity in the N-linked glycan structure of mAbs, and such heterogeneity has a significant influence on the clinical safety and efficacy of mAb drugs. We previously proposed a constraint-based modeling method called glycosylation flux analysis (GFA) to characterize the rates (fluxes) of intracellular glycosylation reactions and applied the method to examine the N-linked glycosylation of immunoglobulin G (IgG) in fed-batch Chinese hamster ovary (CHO) fed-batch cultivations. In this work, we significantly improved the computational efficiency of the GFA, and employed the method to analyze the glycosylation of IgG in continuous perfusion CHO cultivations. Perfusion cell cultures have several advantages over the traditional (fed-)batch operation, including higher productivity per unit volume of reactor and more consistent product quality. The GFA showed that as in the fed-batch cultivation, the dynamical changes of IgG glycan heterogeneity in the perfusion culture are mainly attributed to alterations in the galactosylation flux activity. Furthermore, a regression analysis of the galactosylation flux activity using random forest regression linked the dynamics of galactosylation activity with the cell-specific productivity of IgG and the extracellular ammonia concentration.
REVIEW | doi:10.20944/preprints202209.0233.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: COVID-19 prophylaxis; COVID-19 treatment; Kidney transplantation; Vaccination; Monoclonal antibodies; Small antivirus molecules
Online: 16 September 2022 (02:00:02 CEST)
Abstract Kidney transplant recipients, because of a weak immune response due to the assumption of immunosuppressant are exposed to the risk of COVID-19 infection. This fact realize the problem on how to treat the severe infection without carrying the risk of acute rejection due to the reduction of the immunosuppressive drugs. The best are the prophylactic measures to be taken before transplantation as vaccination. If the patient is already transplanted, three measures may be undertaken: Vaccination, use of monoclonal antibodies, use of therapeutic antiviral small molecules. Concerning vaccination is still debated which one is the best and how many doses should be given. The surge of new virus variant is the major problem and invites to find new active vaccines. In addition, not all the transplanted patients develop antibodies. The other measure is the use of monoclonal antibodies. They may be used as prophylaxis or in the early stage of the disease. Finally, the antiviral small molecules may be used again as prophylaxis or treatment. Their major drawback are the interference with the immunosuppressive drugs and the fact that some of them cannot be administered to patients with low eGFR.
REVIEW | doi:10.20944/preprints202207.0250.v1
Subject: Biology And Life Sciences, Virology Keywords: Emergence of Omicron and its mechanism; mutation and sub-lineages; Monoclonal antibodies; Antiviral drugs
Online: 18 July 2022 (07:48:00 CEST)
With the ongoing COVID pandemic, the emergence of a novel omicron variant in November 2021 has chaos the world. Despite mass vaccination, this omicron has spread rapidly raising concerns around the globe. The Omicron variant has a vast array of mutations as compared to another variant of concern with overall 50 mutations where 30 mutations are present in its spike protein. This mutation has led to immune escape and more transmissibility compared to other variants, including Delta. A cluster of mutations (H655Y, N679K, and P681H) present at the omicron spike protein could aid in transmission. Currently, no virus-specific data are available to predict the efficacy of anti-viral and mAbs drugs. However, two monoclonal antibody drugs: Sotrovimab and Evusheld are authorized for emergency use in COVID patients. This virus is not fading away soon. The easiest solution and less expensive measure to fight against this pandemic are following COVID appropriate protocols.There is need to strengthen the level of research for development of potential vaccines and anti-viral drugs. It is also important to monitor and expand genomic surveillance to keep track of the emergence of new variants thus avoiding the spread of new diseases worldwide. This article highlights the emergence of omicron and vast number of mutation in its protein. In addition, recent advancement in drugs approved by FDA to treat COVID patients has been listed and focused in this paper.
REVIEW | doi:10.20944/preprints202110.0450.v1
Subject: Medicine And Pharmacology, Gastroenterology And Hepatology Keywords: Fibrosis; Integrin; TGFβ; Therapeutic target; Drug; Inhibitor; Monoclonal antibody; α8β1; α11β1; Hepatic stellate cell
Online: 29 October 2021 (10:16:13 CEST)
Huge effort has been devoted to developing drugs targeting integrins over 30 years, because of the primary roles of integrins in the cell-matrix milieu. Five αv-containing integrins, in the 24 family members, have been a central target of fibrosis. Currently, a small molecule against αvβ1 is undergoing a clinical trial for NASH-associated fibrosis as a rare reagent aiming at fibrogenesis. Latent TGFβ activation, a distinct talent of αv-integrins, has been intriguing as therapeutic target. None of the αv-integrin inhibitors, however, has been in the clinical market. αv-integrins commonly recognize an Arg-Gly-Asp (RGD) sequence, and thus the pharmacophore of inhibitors for the 5-integrins is based on the same RGD structure. The RGD preference of the integrins, at the same time, dilutes ligand specificity, as the 5-integrins share ligands containing RGD sequence such as fibronectin. With the inherent little specificity in both drugs and targets, “disease specificity” has become less important for the inhibitors than blocking as many αv-integrins. In fact, an almighty inhibitor for αv-integrins, pan-αv, was in a clinical trial. On the contrary, approved integrin inhibitors are all specific to target integrins, which are expressed in cell-type specific manner: αIIbβ3 on platelets, α4β1, α4β7 and αLβ2 on leukocytes. Herein, “disease specific” integrins would serve as attractive targets. α8β1 and α11β1 are selectively expressed in hepatic stellate cells (HSCs) and distinctively induced upon culture activation. The exceptional specificity to activated HSCs reflects rather “pathology specific” nature of these new integrins. The monoclonal antibodies against α8β1 and α11β1 in preclinical examinations may illuminate the road to the first medical reagents.
Subject: Medicine And Pharmacology, Pathology And Pathobiology Keywords: amyotrophic lateral sclerosis; epigenetics; HERV-K; HERV-W; monoclonal antibody; multiple sclerosis; neurodegeneration; temelimab.
Online: 12 April 2021 (12:17:32 CEST)
Human endogenous retroviruses (HERVs) are ancient retroviral DNA sequences established into germline. They contain regulatory elements and encoded proteins few of which may provide benefits to hosts when co-opted as cellular genes. Their tight regulation is mainly achieved by epigenetic mechanisms which can be altered by environmental factors, e.g. viral infections, leading to HERV activation. Aberrant expression of HERVs associates with neurological disease, such as multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS), inflammatory processes and neurodegeneration. This review summarizes recent advances on the epigenetic mechanisms controlling HERV expression and the pathogenic effects triggered by HERV derepression. The article ends describing new promising therapies targeting HERV elements, one of which, temelimab, has completed phase II trials with encouraging results in treating MS. The information gathered here may turn helpful in the design of new strategies to unveil epigenetic failures behind HERV-triggered disease, opening new possibilities for druggable targets and/or for extending the use of temelimab to treat other associated diseases.
ARTICLE | doi:10.20944/preprints202309.0748.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: SARS-CoV-2; coronavirus; monoclonal antibodies; resistance; nanopore; Sweden; whole-genome sequencing; receptor binding domain
Online: 12 September 2023 (11:14:08 CEST)
Monoclonal antibodies (mAbs) are an important treatment option for COVID-19 caused by SARS-CoV-2, especially in immunosuppressed patients. However, this treatment option can become ineffective due to mutations in the SARS-CoV-2 genome, mainly in the receptor binding domain (RBD) of the spike (S) protein. In the present study 7950 SARS-CoV-2 positive samples from the Uppsala and Örebro regions of central Sweden collected between March 2022 and May 2023 were whole-genome sequenced using next-generation sequencing, mainly with the Nanopore sequencing method. Pango lineages were determined and all single nucleotide polymorphism (SNP) mutations that occurred in these samples were identified. The dominant sublineages changed over time and mutations conferring resistance to currently available mAbs became common. Notable ones are R346T and K444T mutations in the RBD that confer significant resistance against tixagevimab and cilgavimab mAbs. Further, mutations conferring a high-fold resistance to bebtelovimab, such as the K444T and V445P mutations, were also observed in the samples. This study highlights that resistance mutations have over time rendered currently available mAbs ineffective against SARS-CoV-2 in most patients. Therefore, there is a need for continued surveillance of resistance mutations and the development of new mAbs that target more conserved regions of the RBD.
CASE REPORT | doi:10.20944/preprints202301.0469.v1
Subject: Medicine And Pharmacology, Neuroscience And Neurology Keywords: anti-calcitonin gene-related peptide monoclonal antibodies; cluster headache; migraine; real-world; galcanezumab; fremanezumab; comorbidity
Online: 26 January 2023 (04:24:39 CET)
A new treatment option for cluster headache (CH) prevention is needed. Monoclonal antibodies (mABs) against calcitonin gene-related peptide (CGRP) ligands are used as a preventative treatment for migraine. Considering the CGRP’s role in the CH attack’s ignition and upkeep, fremanezumab and galcanezumab have been evaluated for CH preventative treatment. However, only high-dose (300 mg) galcanezumab was proven for episodic CH prevention. We herein report 3 cases of migraine and comorbid CH with previous failures of preventive treatments. The 2 cases were treated with fremanezumab and the one with non-high-dose galcanezumab. All 3 cases showed good results not only on migraine but also on CH attacks. Our report suggested the efficacy of CGRP-mABs for CH prevention. Our cases differed from the cases in the phase 3 trials of CGRP-mABs for CH prevention in the following 2 points. First, the patients had both migraine and comorbid CH. Second, the combined use of CGRP-mABs with preventative drugs for CH, such as verapamil and/or prednisolone, was performed. Future accumulation of real-world data may prove the efficacy of CGRP-mABs for CH prevention.
REVIEW | doi:10.20944/preprints202012.0167.v2
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Matrix metalloproteinase; MMPs; protease; TIMPs; exosite; small molecule inhibitors; monoclonal antibodies; proteomics; N-terminomics; TAILS
Online: 24 March 2021 (16:23:28 CET)
Matrix metalloproteinases (MMPs) have been demonstrated to have both detrimental and protective functions in inflammatory diseases. Several MMP inhibitors, with the exception of Periostat®, have failed in Phase III clinical trials. As an alternative strategy, recent efforts have been focussed on the development of more selective inhibitors or targeting other domains than their active sites (e.g., exosites, ectosites) through specific small molecule inhibitors or monoclonal antibodies. Here, we present some examples that aim to better understand the mechanisms of conformational changes/allosteric control of MMPs functions. In addition to MMP inhibitors, we discuss unbiased global approaches such as proteomics and N-terminomics to identify new MMP substrates and achieve a better understanding of the roles of these proteases in diseases.
COMMUNICATION | doi:10.20944/preprints202012.0823.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: neuroscience; rheumatology; osteoarthritis; pain; peripheral nerve; biological drug; growth factor; peptide; monoclonal antibody; ion channel
Online: 31 December 2020 (15:41:05 CET)
Neuroscience is a vast discipline that deals with the anatomy, biochemistry, molecular biology, physiology and pathophysiology of central and peripheral nerves. Advances made through basic, translational, and clinical research in the field of neuroscience have great potential for long-lasting and beneficial impacts on human health. The emerging field of biological therapy is intersecting with the disciplines of neuroscience and rheumatology, creating new horizons for interdisciplinary and applied research. Biological drugs, growth factors, neuropeptides and monoclonal antibodies are being developed and tested for the treatment of painful arthritic and rheumatic diseases. This concise communication focuses on the solutions provided by the fields of neuroscience and neuroimmunology for real-world clinical problems in the field of rheumatology, focusing on synovial joint pain and the emerging biological treatments that specifically target pathways implicated in osteoarthritis pain in peripheral nerves.
ARTICLE | doi:10.20944/preprints201811.0246.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: monoclonal antibodies; polyclonal antibodies; triazines; enzyme immunoassay; quantitative structure-activity relationship analysis; 3D-QSAR; atrazine
Online: 9 November 2018 (11:36:02 CET)
A common task in the immunodetection of structurally close compounds is to analyze the selectivity of immune recognition: it is required to understand the regularities of immune recognition and to elucidate the basic structural elements which provide it. Triazines are compounds of particular interest for such a research due to their high variability and the necessity of their monitoring to provide safety of agricultural products and foodstuffs. We evaluated the binding of 20 triazines with polyclonal (pAb) and monoclonal (mAb) antibodies obtained using atrazine as the immunogenic hapten. A total of >3000 descriptors was used in QSAR analysis of binding activities (pIC50). Comparison of the two enzyme immunoassay systems showed that the system with pAb is much easier to describe using 2D QSAR methodology, while the system with mAb can be described using the 3D QSAR COMFA. Thus, for the 3D QSAR model of the polyclonal antibodies, the main statistical parameter q2 (‘leave-many-out’) is equal 0.498, and for monoclonal antibodies q2 is equal 0.566. Obviously, in the case of pAb, we deal with several targets, while in the case of mAb the target is one, and therefore it is easier to describe it using specific fields of molecular interactions distributed in space.
REVIEW | doi:10.20944/preprints202012.0419.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: immune checkpoint; lymphoid neoplasms; programmed death 1; cytotoxic T-lymphocyte antigen 4; monoclonal antibodies; combination therapies
Online: 17 December 2020 (08:10:05 CET)
Immunotherapy has been considered for years as a viable and attractive treatment option for patients with cancer. Among immunotherapy arsenal, the targeting of intratumoral immune cells by immune-checkpoint inhibitory agents has recently revolutionized the treatment of several subtypes of tumours. These approaches aimed at restoring an effective anti-tumour immunity, rapidly reached the market thanks to the simultaneous identification of inhibitory signals that dampen an effective antitumor response in a large variety of neoplastic cells, and the clinical development of monoclonal antibodies targeting checkpoint receptors. Leading therapies in solid tumours are mainly focused on the cytotoxic T-lymphocyte–associated antigen 4 (CTLA-4) and programmed-death 1 (PD-1) pathways. These approaches have found a promising testing ground in both Hodgkin lymphoma and non-Hodgkin lymphoma, mainly because in these diseases the malignant cells interact with the immune system and commonly provide signals that regulate immune function. Although several trials have already demonstrated evidence of therapeutic activity with some checkpoint inhibitors in lymphoma, many of the immunologic lessons learned from solid tumours may not directly translate to lymphoid malignancies. In this sense, the mechanisms of effective antitumor responses are different between the different lymphoma subtypes, while the reasons for this substantial difference remain partially unknown. This review will discuss the current advances of immune-checkpoint blockade therapies in B-cell lymphoma and will build a projection of how the field may evolve in the near future. In particular, we will analyze the current strategies being evaluated both preclinically and clinically with the aim to foster the use of immune-checkpoint inhibitors in non-Hodgkin lymphoma, including combination approaches with chemotherapeutics, biological agents and/or different immunologic therapies.
REVIEW | doi:10.20944/preprints202101.0471.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: aptamer; aptasensor; diagnosis; imaging; sequencing; therapeutics; probes; fluorescence; pathogenic bacteria; cancer cells; monoclonal antibodies; SELEX; nucleic acids
Online: 25 January 2021 (10:18:16 CET)
Issues presented by the application of monoclonal antibodies in diagnostic assays and as curative agents can make the use of such molecules cost-prohibitive and sometimes even unsafe. This has warranted the development of short single-stranded oligonucleotides known as Aptamers. The structural malleability of these short DNA or RNA nucleotide segments allows them to exist in distinct conformations. SELEX (Systematic Evolution of Ligands by Exponential Enrichment) is a multi-step process for synthesis of aptamers. Each step of this procedure is governed by a diverse set of factors that influence production efficiency, binding affinity, and specificity of the oligonucleotides. Headway in aptamer research has been made in recent years by the introduction of newer iterations of the SELEX process. A greater number of studies are now being carried out to incorporate aptamers into existing disease detection tools and therapies. An overview has been given first on the key aptamer properties and the process of their production (with its newer iterations), contrasting each of them with that of monoclonal antibodies. Possible manifold applications afforded due to unique aptamer characteristics are also discussed. A keen review is further provided on the design, development and use of fluorescent aptamers in bioimaging, sequencing or profiling, and treatment of pathogenic bacteria and tumor cells.
ARTICLE | doi:10.20944/preprints202310.0759.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: pore-forming toxin; monoclonal antibodies; epitope; site-directed mutagenesis, enzyme immunoassay, phage display; modeling of three-dimensional structure
Online: 12 October 2023 (04:37:50 CEST)
Hemolysin II (HlyII) – one of the pathogenic factors of Bacillus cereus, a pore-forming β-barrel toxin – possesses a C-terminal extension of 94 amino acid residues, designated as the C-terminal domain of HlyII (HlyIICTD), which plays an important role in the functioning of the toxin. Our previous work described a monoclonal antibody (HlyIIC-20), capable of strain-specific inhibi-tion of hemolysis caused by HlyII, and demonstrated the dependence of the efficiency of hemol-ysis on the presence of proline at position 324 in HlyII outside the conformational antigenic de-terminant. In this work, we studied 16 mutant forms of HlyIICTD. Each of the mutations, ob-tained by multiple site-directed mutagenesis leading to the replacement of amino acid residues lying on the surface of the 3D structure of HlyIICTD, led to a decrease in the interaction of HlyIIC-20 with the mutant form of the protein. Changes in epitope structure confirm the high conformational mobility of HlyIICTD required for the functioning of HlyII. Comparison of the effect of the introduced mutations on the effectiveness of interaction between HlyIICTD and HlyIIC-20 and a control antibody recognizing a non-overlapping epitope enabled identifying the amino acid residues N339, K340 included in the conformational antigenic determinant rec-ognized by HlyIIC-20.
REVIEW | doi:10.20944/preprints202112.0525.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: colorectal cancer; immunotherapy; checkpoint blockade; adoptive cell therapy; monoclonal antibodies; oncolytic viruses; anti-cancer vaccines; cytokine; T cell; NK cell
Online: 31 December 2021 (15:14:39 CET)
Though early-stage colorectal cancer has a high 5-year survival rate of 65-92% depending on the specific stage, this probability drops to 13% after the cancer metastasizes. Frontline treatments for colorectal cancer such as chemotherapy and radiation often produce dose-limiting toxicities in patients and acquired resistance in cancer cells. Additional targeted treatments are needed to improve patient outcomes and quality of life. Immunotherapy involves treatment with peptides, cells, antibodies, viruses, or small molecules to engage or train the immune system to kill cancer cells. Preclinical and clinical investigations of immunotherapy for treatment of colorectal cancer including immune checkpoint blockade, adoptive cell therapy, monoclonal antibodies, oncolytic viruses, anti-cancer vaccines, and immune system modulators have been promising, but demonstrate limitations for patients with proficient mismatch repair enzymes. In this review, we discuss preclinical and clinical studies investigating immunotherapy for treatment of colorectal cancer and predictive biomarkers for response to these treatments. We also consider open questions including optimal combination treatments to maximize efficacy, minimize toxicity, and prevent acquired resistance and approaches to sensitize mismatch repair proficient patients to immunotherapy.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Human induced pluripotent stem cells (hiPSCs); monoclonal antibodies; R-10G; R-17F; keratan sulfate; podocalyxin; keratanase II; endo-β-galactosidase
Online: 9 March 2021 (12:13:56 CET)
We developed two human induced pluripotent stem cell (hiPSC)/human embryonic stem cell-specific glycan-recognizing mouse antibodies, R-10G and R-17F, using the Tic (JCRB1331) hiPSC line as an antigen. R-10G recognizes a low-sulfate keratan sulfate, and R-17F recognizes lacto-N-fucopentaose-1. To evaluate the general characteristics of stem cell glycans, we used the hiPSC line 201B7 (HPS0063), a prototype iPSC line. Using an R-10G affinity column, an R-10G-binding protein was isolated. The protein yielded a single but very broad band from 480 to 1,236 kDa by blue native gel electrophoresis. After trypsin digestion, the protein was identified as podocalyxin by liquid chromatography/mass spectrometry. According to Western blotting, the protein reacted with R-10G and R-17F. The R-10G positive band was resistant to digestion with glycan-degrading enzymes, including peptide N-glycanase, but the intensity of the band was decreased significantly by digestion with keratanase, keratanase II, and endo-β-galactosidase, suggesting the R-10G epitope to be a keratan sulfate. These results suggest that keratan sulfate-type epitopes are shared by hiPSCs. However, the keratan sulfate from 201B7 cells contained a polylactosamine disaccharide unit (Galβ1-4GlcNAc) at a significant frequency, whereas that from Tic cells consisted mostly of keratan sulfate disaccharide units (Galβ1-4GlcNAc(6S)). In addition, the abundance of the R-10G epitope was significantly lower in 201B7 cells than in Tic cells.
REVIEW | doi:10.20944/preprints202304.1141.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: biosimilarity; biosimilars; pharmacodynamic biomarkers; monoclonal antibodies; FDA; clinical efficacy testing in healthy subjects; clinical efficacy testing in patients; functional assays; receptor binding
Online: 28 April 2023 (08:03:20 CEST)
The FDA has concluded that a biosimilar candidate capable of demonstrating pharmacodynamic biomarkers in a healthy subject need not be tested for clinical efficacy in patients, regardless of if the biomarker correlates with clinical response. Since monoclonal antibodies (mAbs) do not trig-ger pharmacodynamic response, they can be substituted with robust functional disqualifying them for this waiver that can be overcome by allowing comparison of functional properties that eventually result in clinical response. This suggestion is based on the FDA's preference for more sensitive testing methods. However, clinical efficacy testing in patients is the least sensitive method, as confirmed by statistical modeling, a fact that regulatory agencies need to admit. In this paper, I present a logical and rational argument to establish the biosimilarity of products that do not have pharmacodynamic biomarkers based on their orthogonally proven functional bio-similarity. This understanding will significantly lower the development cost of biosimilars, a goal that the FDA outlined in all its guidance. Keywords: biosimilarity 1; biosimilars 2; pharmacodynamic biomarkers 3; monoclonal antibodies 4; FDA 5; clinical efficacy testing in healthy subjects 6; clinical efficacy testing in patients 7; functional assays 8; receptor binding 9.
ARTICLE | doi:10.20944/preprints202302.0176.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: acute myocardial infarction (AMI); cardiac Troponin I (cTnI); chemiluminescence; biosensor; luminol; monoclonal antibody; flow injection assay; microfluidic system; monolithic column; protein expression
Online: 10 February 2023 (02:58:24 CET)
Cardiac vascular diseases, especially acute myocardial infarction (AMI), are one of the leading causes of death worldwide. Therefore cardio-specific biomarkers such as cardiac Troponin I (cTnI) play an essential role in diagnostics. In order to enable rapid and accurate measurement of cTnI with the potential of online measurements, a proof of concept of a chemiluminescence-based biosensor is presented. A flow cell was designed and combined with a sensitive CMOS camera allowing an optical readout. In addition, a microfluidic setup was established, and cTnI was determined selectively. The biomarker cTnI was expressed in E. coli, and its characterization and correct folding were investigated by different analytical methods. This recombinant cTnI was used for enzyme-linked immunosorbent assays (ELISA), calibrated against commercially available recombinant cTnI, and applied for the biosensor measurements. Based on chemiluminescence detection, the biosensor was successfully tested, and the cTnI biomarker could be reproducibly determined in buffer, spiked blood serum, and plasma.
ARTICLE | doi:10.20944/preprints202203.0229.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: SARS-CoV-2 antibody; reproducibility crisis; peptide mass fingerprinting; monoclonal antibody; trace-ability; identity; antibody identification; antibody light chain; MALDI-TOF-MS
Online: 16 March 2022 (10:01:41 CET)
During the SARS-CoV-2 pandemic, many virus-binding monoclonal antibodies have been developed for clinical and diagnostic purposes. This underlines the importance of antibodies as universal bioanalytical reagents. However, little attention is given to the reproducibility crisis that scientific studies are still facing to date. In a recent study, not even half of all research antibodies mentioned in publications could be identified at all. This should spark more efforts in the search for practical solutions for the traceability of antibodies. For this purpose, we used thirty-five monoclonal antibodies against SARS-CoV-2 to demonstrate how sequence-independent antibody identification can be achieved by simple means applied onto the protein. First, we examined the intact and light chain masses of the antibodies relative to the reference material NIST-mAb 8671. Already half of the antibodies could be identified based solely on these two parameters. In addition, we developed two complementary peptide mass fingerprinting methods with MALDI-TOF-MS that can be performed in 45 minutes and had a combined sequence coverage of over 80%. One method is based on the partial acidic hydrolysis of the protein by 5 mM of sulfuric acid at 99 °C. Furthermore, we established a fast way for a tryptic digest without an alkylation step. We were able to show that the distinction of clones is possible simply by a brief visual comparison of the mass spectra. In this work, two clones originating from the same immunization gave the same fingerprints. Later, a hybridoma sequencing confirmed the sequence identity of these sister clones. In order to automate the spectral comparison for larger libraries of antibodies, we developed the online software ABID 2.0 (https://gets.shinyapps.io/ABID/). This open-source software determines the number of matching peptides in the fingerprint spectra. We propose that publications and other documents critically relying on monoclonal antibodies with unknown amino acid sequences should include at least one antibody fingerprint. By fingerprinting an antibody in question, its identity can be confirmed by comparison with a library spectrum at any time and context.
REVIEW | doi:10.20944/preprints202310.1723.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: molecular tweezers; cation-pi interactions; intrinsic disorder, protein-protein interactions; hydrophobic interaction chromatography, monoclonal antibody production; protein aggregation; protein refolding; arginine methyltransferases; post-translational modification
Online: 27 October 2023 (05:51:26 CEST)
Arginine shows Jekyll and Hyde behavior in several respects. It participates in protein folding via ionic and H-bonds and cation-pi interactions; the charge and hydrophobicity of its side chain makes it a disorder-promoting amino acid. Its methylation in histones; RNA binding proteins; chaperones regulates several cellular processes. The arginine-centric modifications are important in oncogenesis and as biomarkers in several cardiovascular diseases. The cross-links involving arginine in collagen and cornea are involved in pathogenesis of tissues but have also been useful in tissue engineering and wound-dressing materials. Arginine is a part of active site of several enzymes such as GTPases, peroxidases, and sulfotransferases. Its metabolic importance is obvious as it is involved in production of urea, NO, ornithine and citrulline. It can form unusual functional structures such as molecular tweezers in vitro and sprockets which engage DNA chains as part of histones in vivo. It has been used in design of cell-penetrating peptides as drugs. Arginine has been used as an excipient in both solid and injectable drug formulations; its role in suppressing opalescence due to liquid-liquid phase separation is particularly very promising. It has been known as a suppressor of protein aggregation during protein refolding. It has proved its usefulness in protein bioseparation processes like ion-exchange, hydrophobic and affinity chromatographies. Arginine is an amino acid, whose importance in biological sciences and biotechnology continues to grow in diverse ways.
ARTICLE | doi:10.20944/preprints202212.0542.v2
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: safety analysis; targeted therapy; monoclonal antibody therapy; immune checkpoint inhibibitors; tyrosine kinase inhibitors; breast cancer; gynecological cancer; Helixor; Viscum album L.; PARP inhibitors; CDK 4/6 inhibitors
Online: 30 December 2022 (12:00:35 CET)
Background: Newer personalized medicine including targeted therapies such as PARP inhibitors and CDK 4/6 inhibitors have shown to improve survival of breast and gynaecological cancer patients. However, efficacy outcomes may be hampered by treatment discontinuation due to targeted therapy-related adverse drug reactions or resistance. Studies suggest that add-on mistletoe (Viscum album L., VA) improves quality of life and ameliorates cytotoxic side effects of standard oncological therapy in cancer patients. The primary objective of this real-world data study was to determine the safety profile of targeted therapy in combination with add-on Helixor® VA therapy in breast and gynecological cancer patients. Methods: The present study is a real-world data study utilizing demographic and treatment data from the accredited national Network Oncology (NO) registry. The study has received ethics approval. The safety profile of targeted with or without Helixor® VA therapy as well as safety - associated variables were evaluated by univariate and adjusted multivariable regression analyses. Results: All stage breast or gynecological cancer patients (n = 242) were on average 54.5±14.2 years old. One hundred and sixty patients (66.1%) were in the control (CTRL, targeted therapy) and 82 patients (33.9%) in the combinational (COMB, targeted plus Helixor® VA therapy) group. The addition of Helixor® VA did not hamper the safety profile (χ2 = 0.107, p-value = 0.99) of targeted therapy. Furthermore, no adverse events and a trend towards an improved targeted therapy adherence were observed in the COMB group. Conclusions: The present study is the first of its kind showing the applicability of Helixor® VA in combination with targeted therapies. The results indicate that add-on Helixor® VA does not negatively alter the safety profile of targeted therapies in breast and gynaecological cancer patients.
ARTICLE | doi:10.20944/preprints202007.0039.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Aviation security; biosensor; flow injection assay; monoclonal antibody; fluorescence microscope; lab-on-a-chip; microfluidic systems; antibody labeling; CMOS; diode laser; monolithic column; laser-induced fluorescence detector (LIF)
Online: 3 July 2020 (12:26:26 CEST)
The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports arenas, theaters, and other large buildings. Security in these environments can be achieved by a set of different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of TNT occurring, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled CMOS camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of the explosive 2,4,6-trinitrotoluene (TNT). The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by PETN, RDX, and HMX. This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds.
ARTICLE | doi:10.20944/preprints202107.0521.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Online detection, security; biosensor; flow injection assay; monoclonal antibody; fluorescence microscope; lab-on-a-chip; microfluidic systems; antibody labeling; CMOS; diode laser; monolithic column; laser-induced fluorescence detector (LIF); low-cost; high-speed; non-competitive immunoassay; immunometric assay
Online: 22 July 2021 (14:13:46 CEST)
The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue in public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect ultra-small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 23 pM (7 ppt) of cocaine with a response time of 90 seconds and a total assay time below 3 minutes. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement.