ARTICLE | doi:10.20944/preprints202111.0287.v1
Subject: Life Sciences, Microbiology Keywords: Excretory-secretory products; Angiostrongylus cantonensis; Astrocytes; Benzaldehydes; endoplasmic reticulum stress; oxidative stress
Online: 16 November 2021 (11:34:13 CET)
Excretory-secretory products (ESPs) are the main research targets for investigating the hosts and helminths interaction. Parasitic worms can migrate to parasitic sites and avoid the host immune response by secreting this product. Angiostrongylus cantonensisis an important food-borne zoonotic parasite that causes severe neuropathological damage and symptoms, including eosinophilic meningitis or meningoencephalitis in humans. Benzaldehydes are organic compounds composed of a benzene ring and formyl substituents. This compound has anti-inflammatory and antioxidation properties. Previous studies showed that 3-hydroxybenzaldehyde (3-HBA) and 4-hydroxybenzaldehyde (4-HBA) can reduce apoptosis in A. cantonensis ESPs treated astrocytes. These results on the protective effect underlying benzaldehyde have primarily focused on cell survival. The study was designed to investigate the molecular mechanisms of endoplasmic reticulum stress (ER stress) and oxidative stress in astrocytes in A. cantonensis ESPs treated astrocytes and to evaluate the therapeutic consequent of 3-HBA and 4-HBA. First, we initially established the RNA-seq dataset in each group, including Normal, ESPs, ESPs+3-HBA, and ESPs+4-HBA. We also found that benzaldehyde (3-HBA and 4-HBA) can stimulate astrocytes to express ER stress-related molecules after ESP treatment. The level of oxidative stress could also be decreased in astrocytes by elevating antioxidant activity and reducing ROS generation. These results suggested that benzaldehyde may be a potential therapeutic compound for human angiostrongyliasis to support brain cell survival by inducing the expression levels of ER stress- and oxidative stress-related pathway.
ARTICLE | doi:10.20944/preprints202210.0264.v1
Subject: Medicine & Pharmacology, General Medical Research Keywords: Secretory leucoprotease inhibitor; SLPI; inflammation; infection; Pseudomonas
Online: 19 October 2022 (03:59:12 CEST)
Secretory leucoprotease inhibitor (SLPI) has multifaceted functions, including inhibition of protease activity, antimicrobial functions, and anti-inflammatory properties. In this study, we show that SLPI plays a role in controlling pulmonary P. aeruginosa infection. Mice lacking SLPI were highly susceptible to P. aeruginosa infection, however had no difference in bacterial burden. Utilising a model of P. aeruginosa LPS-induced lung inflammation, human recombinant SLPI (hrSLPI) administered intraperitoneally suppressed the recruitment of inflammatory cells in the bronchoalveolar lavage fluid (BALF) and resulted in reduced BALF and serum levels of inflammatory cytokines and chemokines. This anti-inflammatory effect of hrSLPI was similarly demonstrated in a systemic inflammation model induced by intraperitoneal injection of LPS from various bacteria or lipoteichoic acid, highlighting the broad anti-inflammatory properties of hrSLPI. Moreover, in bone-marrow-derived macrophages, hrSLPI reduced LPS-induced phosphorylation of p-IkB-α, p-IKK-α/β, p-P38, demonstrating that the anti-inflammatory effect of hrSLPI was due to the inhibition of the NFB and MAPK pathways. In conclusion, administration of hrSLPI attenuates excessive inflammatory responses and is therefore, a promising strategy to target inflammatory diseases such as acute respiratory distress syndrome or sepsis and could potentially be used to augment antibiotic treatment.
ARTICLE | doi:10.20944/preprints201906.0031.v1
Subject: Biology, Plant Sciences Keywords: avirulence; resistance; avrPi54; secretory protein; localization; particle bombardment
Online: 4 June 2019 (12:58:01 CEST)
Plant pathogens utilize effectors to subvert host cell biology for facilitating infection. However certain effectors, called as the avirulence proteins, trigger immune responses in the host. AvrPi54 is an avirulence protein from fungus Magnaporthe oryzae which induces the defense reactions in rice cells that contain Pi54 resistance gene. The characterization of such proteins and elucidation of their function facilitate the understanding of the mechanism of disease establishment. In present study, physiochemical properties of AvrPi54 were analysed using computational methods. We found that mature AvrPi54 is a small, hydrophobic and secretary protein with 134 amino acids. It is rich in small amino acids with no significant homology with other proteins in databases. The gene ORF was cloned in pET28a(+) vector and expressed in E. coli BL21(DE3)pLysS. The protein was purified using affinity chromatography. Transient expression of the gene in epidermal cells of onion bulb is a powerful tool to predict the subcellular localization in plant cells. We fused AvrPi54 to eYFP and transformed epidermal cell layer of onion bulb. Fused protein localized to the plasma membrane and nucleus of plant cells. Therefore, AvrPi54 might be functioning in the host cell as transcription factor or chromatin remodelling factor to modify pathogenesis-related processes.
REVIEW | doi:10.20944/preprints202207.0160.v2
Subject: Life Sciences, Cell & Developmental Biology Keywords: Cellular Senescence Network; Normal Aging; Senescence; Senescence-associated secretory phenotype; SenNet
Online: 15 September 2022 (12:52:05 CEST)
Cells respond to a myriad of stressors by senescing, acquiring stable growth arrest, morphologic and metabolic changes, and a senescence-associated-secretory-phenotype (SASP). The heterogeneity of senescent cells (SnCs) and their SASP is vast, yet poorly characterized. SnCs have diverse roles in health and disease and are therapeutically targetable, making characterization of SnCs and harmonization of their nomenclature a priority. The Cellular Senescence Network (SenNet), a NIH Common Fund initiative, will leverage emerging single cell and spatial-omics to identify and map SnCs in numerous organs across the lifespan of humans and mice. A common coordinate framework will integrate the data, using validated, standardized methods, creating public 4-dimensional SnC atlases. Key SenNet deliverables include development of innovative tools/technologies to detect SnCs, biomarker discovery, common annotations to describe SnCs and extensive public data sets. The goal is to comprehensively understand and map SnCs for diagnostic and therapeutic purposes to improve human health.
REVIEW | doi:10.20944/preprints202207.0423.v1
Subject: Life Sciences, Cell & Developmental Biology Keywords: Aging; cellular senescence; fibroblast; osteoarthritis; remodeling-associated secretory phenotype (RASP); remodeling activation
Online: 27 July 2022 (13:38:36 CEST)
One of the most striking findings in biogerontology in the 2010s was the demonstration that elimination of senescent cells delays many late-life diseases and extends lifespan in mice. This implied that accumulation of senescent cells promotes late-life diseases, particularly through action of senescent cell secretions (the senescence-associated secretory phenotype or SASP). But what exactly is a senescent cell? Subsequent to the initial characterization of cellular senescence it became clear that, prior to aging, this phenomenon is in fact adaptive. It supports tissue remodeling functions in a variety of contexts, including embryogenesis, parturition and acute inflammatory processes that restore normal tissue architecture and function, such as wound healing, tissue repair after infection, and amphibian limb regeneration. In these contexts such cells are normal and healthy, and not in any way senescent in the true sense of the word, as originally meant by Hayflick. Thus, it is misleading to refer to them as “senescent”. Similarly, the common assertion that senescent cells accumulate with age due to stress and DNA damage is no longer safe, particularly given their role in inflammation - a process that becomes persistent in later life. We therefore suggest that it would be useful to update some terminology, to bring it into line with contemporary understanding, and to avoid future confusion. To open a discussion of this issue, we propose replacing the term cellular senescence with remodeling activation, and SASP with RASP (remodeling-associated secretory phenotype).
ARTICLE | doi:10.20944/preprints202105.0012.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Secretory Phospholipase A2, Bothrops jararacussu, Oxidative Stress, Edema, Myonecrosis and Thiol Dependent Antioxidant
Online: 3 May 2021 (16:15:40 CEST)
Background: Clinical cases reports with snake accidents show that venom bite induces increased oxidative stress including several markers of lipid peroxidation and other oxidative stress marker in plasma. Methods: The main findings of this work were performed with BthTx-II on paw edema of animals treated with the toxin and biochemical measurement of COX-2, PGE2, MDA and the effects of peroxiredoxin inhibitors on edema and myotoxicity were also evaluated. Results: The results show that edema and myotoxocity induced by PLA2 (BthTx-II) induces a strong mobilization of arachidonic acid and an increase in cellular oxidative stress as measured by increased malondialdehydo (MDA) concentration and protein carbonylation. Thus, these findings establish the strong link between oxidative stress, arachidonic acid mobilization and that these events may explain the presence of oxidative stress markers in snake-bitten patients. Experiments performed with animals previously treated with commercially purchased inhibitors showed enzymes such as thioredoxin (TXN), thioredoxin reductase (TXNRD) and other glutathione (GSH)-related antioxidant defenses could play an essential role controlling and defining the end of edema on the late phase of PLA2 BthTx-II-induced process. Conclusion. This study showed that thioate-dependent antioxidant enzymes play an important role in resolving the edema induced by BthTx-II.
ARTICLE | doi:10.20944/preprints202008.0702.v1
Subject: Biology, Plant Sciences Keywords: acylsugar; wild tomato; Solanum pennellii; secretory glandular trichome; specialized metabolism; intraspecific variation; metabolomics
Online: 31 August 2020 (05:15:08 CEST)
Acylsugars constitute an abundant class of pest- and pathogen-protective Solanaceae family plant specialized metabolites produced in secretory glandular trichomes. Solanum pennellii produces copious triacylated sucrose and glucose esters, and the core biosynthetic pathway producing these compounds was previously characterized. We performed untargeted metabolomic analysis of S. pennellii surface metabolites from accessions spanning the species range, which indicated geographic trends in acylsugar profile and revealed two compound classes previously undescribed from this species, tetraacylglucoses and flavonoid aglycones. A combination of ultrahigh performance liquid chromatography high resolution mass spectrometry (UHPLC-HR-MS) and NMR spectroscopy identified variations in number, length, and branching pattern of acyl chains, and the proportion of sugar cores in acylsugars among accessions. The new dimensions of acylsugar variation revealed by this analysis further indicate variation in the biosynthetic and degradative pathways responsible for acylsugar accumulation. These findings provide a starting point for deeper investigation of acylsugar biosynthesis, an understanding of which can be exploited through crop breeding or metabolic engineering strategies to improve endogenous defenses of crop plants.
REVIEW | doi:10.20944/preprints202208.0498.v1
Subject: Life Sciences, Immunology Keywords: Secretory IgA; IgA class switching; SARS-CoV-2; respiratory pathogens; nasal vaccines; vaccine adjuvants
Online: 30 August 2022 (02:33:19 CEST)
Nasal cavity is a primary checkpoint for the invasion of several respiratory pathogens. Numerous pathogens including SARS-CoV-2, S. pneumonia, S. aureus, etc., adhere to the nasal epithelium or mucus to invade and trigger an infection. IgA serves as the first line of defense against foreign antigens and pathogens. They exhibit cross-reactivity against a diverse variety of antigens through immune exclusion, which intercepts the invasion of pathogens through the mucosal lining. Advances in intranasal immunization technology underscore the elevated neutralizing IgA levels at local and distal mucosa in contrast to the parenteral vaccines. This review highlights the adjuvants that induce IgA class switching and the challenges of maintaining nominal IgA levels at the mucosal surface. Finally, the review features the paradigm-shifting of conventional immunization techniques to IgA-inducing vaccines to enhance protection against homologous and heterologous pathogens.
CONCEPT PAPER | doi:10.20944/preprints201804.0358.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: snakebite; antidote; inhibitor; small molecule therapeutics; SMT; secretory phospholipase; sPLA2; Neglected Tropical Disease; NTD
Online: 27 April 2018 (09:00:55 CEST)
The World Health Organization (WHO) recently added snakebite envenoming to the priority list of Neglected Tropical Diseases (NTD). It is thought that ~75% of mortality following snakebite occurs outside the hospital setting, making the temporal gap between a bite and antivenom administration a major therapeutic challenge. Small molecule therapeutics (SMTs) have been proposed as potential pre-referral treatments for snakebite to help address this gap. Herein, we discuss the characteristics, potential uses and development of SMTs as potential treatments for snakebite envenomation. We focus on SMTs that are secretory phospholipase A2 (sPLA2) inhibitors and metalloprotease (MP) inhibitors.
CASE REPORT | doi:10.20944/preprints201803.0211.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: MTC; calcitonin; parafollicular C cells; secretory granules; immunofluorescence; ultrastructure; transmission electron microscopy; ERBB1; ERBB2
Online: 26 March 2018 (09:05:18 CEST)
Medullary thyroid carcinomas (MTCs) are rare thyroid tumors occurring in both sporadic and hereditary forms and whose pathogenesis is related to RET proto-oncogene alterations. MTCs originate from parafollicular cells, which produce calcitonin that represents the biochemical activity of MTC. Total thyroidectomy is the main treatment for MTC and often cures patients with confined diseases. In cases of metastasis, the approach depends on the rate of progression of disease. We report a case of a 54 years old female with a single, incidentally discovered, thyroid nodule of 1 cm, classified as suspicious MTC after a stimulation test with i.v. calcium. After surgery, we examined the nodule using immunohistochemistry, immunofluorescence and electron microscopy. In addition to calcitonin, we found that it expressed intracellular positivity for the RTK receptors ERBB1 and ERBB2. Consistently with MTC features, ultrastructural examination of the tumor displayed heterogeneous spindle-shaped cells containing two groups of secretory granules. Due to the significant correlation found between high ERBB1/ERBB2 levels in MTCs and extrathyroidal growth, the detection of ERBB1 and ERBB2 expression suggests that the two oncoproteins may possibly be involved in tumor proliferative responses and/or differentiation of C-cells. The biological, prognostic and therapeutic significance of these patterns would merits further investigations.
ARTICLE | doi:10.20944/preprints202111.0124.v1
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: tuberculosis; secretory antigens; bronchiolar epithelium; alveolar pneumocytes; M2 polarization; COX-2, FAS; Pathogenesis; early lesion
Online: 5 November 2021 (14:50:58 CET)
The characteristic lesion of primary tuberculosis is the granuloma as is widely studied in human tissues and animal models. Post-primary tuberculosis is different. It develops only in human lungs and begins as a prolonged subclinical obstructive lobular pneumonia that slowly accumulates mycobacterial antigens and host lipids in alveolar macrophages with nearby highly sensitized T cells. After several months, the lesions undergo necrosis to produce a mass of caseous pneumonia large enough to fragment and be coughed out to produce a cavity or be retained as the focus of a post-primary granuloma. Here we extend these findings with the demonstration of mycobacterial antigen, but not AFB, of M. tuberculosis in the cytoplasm of ciliated bronchiolar epithelium and alveolar pneumocytes in association with elements of the programmed death ligand 1 (PD-L1), cyclo-oxygenase (COX)-2, and fatty acid synthase (FAS) pathways in the early lesion. This suggests that M. tuberculosis uses its secreted antigens to coordinate prolonged subclinical development of the early le-sions in preparation for a necrotizing reaction sufficient to produce a cavity, post-primary granulomas and fibrocaseous disease.
ARTICLE | doi:10.20944/preprints202107.0404.v2
Subject: Medicine & Pharmacology, Pathology & Pathobiology Keywords: tuberculosis; secretory antigens; bronchiolar epithelium; alveolar pneumocytes; M2 polarization; COX-2, FAS; Pathogenesis; early lesion
Online: 29 September 2021 (09:56:22 CEST)
The characteristic lesion of primary tuberculosis is the granuloma as is widely studied in human tissues and animal models. Post-primary tuberculosis is different. It develops only in human lungs and begins as a prolonged subclinical obstructive lobular pneumonia that slowly accumulates mycobacterial antigens and host lipids in alveolar macrophages with nearby highly sensitized T cells. After several months, the lesions under necrosis to produce a mass of caseous pneumonia large enough to fragment and be coughed out to produce a cavity or be retained as the focus of a post-primary granuloma. Here we extend these findings with the demonstration of mycobacterial antigen, but not AFB, of M. tuberculosis in the cytoplasm of ciliated bronchiolar epithelium and alveolar pneumocytes in association with elements of the programmed death ligand 1 (PD-L1), cyclo-oxygenase (COX)-2, and fatty acid synthase (FAS) pathways in the early lesion. This suggests that M. tuberculosis use its secreted antigens to coordinate prolonged subclinical development of the early lesions in preparation for a necrotizing reaction sufficient to produce a cavity, post-primary granulomas and fibrocaseous disease
REVIEW | doi:10.20944/preprints201909.0144.v1
Subject: Life Sciences, Immunology Keywords: immunoglobulin; IVIG; LcrV; PcrV; translocation; type III secretory toxin; type III secretion system; V-antigen
Online: 14 September 2019 (19:18:28 CEST)
The mechanisms underlying the effects of γ-globulin therapy for bacterial infections are thought to involve bacterial cell lysis via complement activation, phagocytosis via bacterial opsonization, toxin neutralization, and antibody-dependent cell-mediated cytotoxicity. Nevertheless, recent advances in the study of pathogenicity in gram-negative bacteria have raised the possibility of an association between γ-globulin and bacterial toxin secretion. Over time, new toxin secretion systems like the type III secretion system have been discovered in many pathogenic gram-negative bacteria. With this system, the bacterial toxins are directly injected into the cytoplasm of the target cell through a special secretory apparatus without any exposure to the extracellular environment and, therefore, with no opportunity for antibodies to neutralize the toxin. However, because antibodies against the V-antigen, which is located on the needle-shaped tip of the bacterial secretion apparatus, can inhibit toxin translocation, this raises the hope that the toxin might be susceptible to antibody targeting. Because multi-drug resistant bacteria are now prevalent, inhibiting this secretion mechanism is attractive as an alternative or adjunctive therapy against lethal bacterial infections. Thus, it would not be unreasonable to define the blocking effect of anti-V-antigen antibodies as the fifth mechanism for immunoglobulin action against bacterial infections.
REVIEW | doi:10.20944/preprints202301.0420.v1
Subject: Life Sciences, Microbiology Keywords: Cryptococcus; extracellular protease; biofilm, secretory vesicles; hypoxia; hydrolytic enzyme; homeostasis; transcription factors; membrane permeases; membrane transporters
Online: 24 January 2023 (03:08:39 CET)
In this review, we present several extracellular proteases, enzymes, membrane permeases, and transporters as essential accessories proteins for nutrient assimilation, conservation, and transportation as determined by nutrient repletion or depletion. As an obligate aerobic pathogen, it is crucial for invading Cryptococcus (C.) neoformans to negotiate its adaptation to human internal organs like the brain and spinal cord, where the oxygen level is low compared to peripheral organs. Besides, essential metals like copper and iron are important cofactors to functional proteins; however, these metals are not usually freely available to invading human pathogens. Again, the phagolysosome low pH with glucose paucity, internal temperature, immune response, and complex extracellular matrixes are challenging environments that must be circumvented by C. neoformans in the systemic tissues for survival, adaptation, and infection in humans. We review extensive works on several extracellular proteases, enzymes, membrane permeases and transporters orchestrated by different transcription factors and present these proteins as weapons needed to outwit systemic resistance to invading pathogens. Lastly, we examine the extracellular secretory vesicles of C. neoformans as “an exosomal virulence bag” that harbours urease, laccase, phosphatase, and capsular components as additional secretory weapons for tissue invasion and persistence.
REVIEW | doi:10.20944/preprints202202.0022.v1
Subject: Life Sciences, Immunology Keywords: exosomes; T lymphocytes; immune synapse; secretory granules; multivesicular bodies; cytotoxic activity; cell death; CAR T lymphocytes
Online: 1 February 2022 (21:33:57 CET)
Extracellular vesicles (EV) are a very heterogeneous group of cell-derived vesicles released by almost all kind of living cells. EV are involved in intercellular communication, both locally and systemically, since they induce signals and transfer their contents (proteins, lipids, RNAs) to other cells, which subsequently trigger a wide variety of biological responses in the target cells. How-ever, cell surface receptor-induced EV release is limited to cells from the immune system, includ-ing T lymphocytes. T cell receptor activation of T lymphocytes induces secretion of EV containing T cell receptor for antigen and several bioactive molecules, including proapoptotic proteins. These EV are thus specific for antigen-bearing cells, which make them ideal candidates for a cell-free, EV-dependent cancer therapy. In this review we discuss the generation of EV by T lymphocytes and some potential therapeutic approaches of these EV.
REVIEW | doi:10.20944/preprints202110.0447.v1
Subject: Life Sciences, Biochemistry Keywords: UPR; IRE1; PERK; ATF6; lipid bilayer stress; ER stress; secretory pathway; hydrophobic mismatch; membrane thickness; membrane stiffness
Online: 29 October 2021 (07:57:29 CEST)
The endoplasmic reticulum (ER) is the major site of membrane biogenesis in most eukaryotic cells. As the entry point to the secretory pathway, it handles more than 10.000 different secretory and membrane proteins. The membrane insertion of proteins, their folding, and ER exit are affected by the lipid composition of the ER membrane and its collective membrane stiffness. The ER is also a hotspot of lipid metabolism for membrane lipids including sterols, glycerophospholipids, ceramides and neural storage lipids. The unfolded protein response (UPR) bears an evolutionary conserved, dual sensitivity to both protein folding-imbalances in the ER lumen and aberrant compositions of the ER membrane, referred to as lipid bilayer stress (LBS). Through transcriptional and non-transcriptional mechanisms, the UPR upregulates the protein folding capacity of the ER and balances the production of proteins and lipids to maintain a functional secretory pathway. In this review, we discuss how UPR transducers sense unfolded proteins and LBS with a particular focus on their role as guardians of the secretory pathway.
REVIEW | doi:10.20944/preprints201908.0186.v1
Subject: Life Sciences, Immunology Keywords: heat shock protein (HSP); extracellular vesicle (EV); exosome; oncosome; immune evasion; resistance-associated secretory phenotype (RASP); EMT; hypoxia; biomarker; liquid biopsy
Online: 17 August 2019 (16:15:01 CEST)
Extracellular vesicles (EV) released by tumor cells are a major aspect of the resistance-associated secretory phenotype (RASP), by which immune evasion can be established. Heat shock proteins (HSPs) are an evolutionarily conserved family of molecular chaperones, which stabilize proteins, minimize protein misfolding and aggregation within the cell, besides facilitating protein translocation, refolding and degradation. (i) Releases of extracellular HSPs (ex-HSP) and EV-associated HSPs (EV-HSP) are essential in RASP, by which molecular cotransfer of HSPs with oncogenic factors into recipient cells can promote cancer progression and resistance against stress such as hypoxia, radiation, chemicals, and immune system. (ii) RASP of tumor cells can eject anticancer drugs, molecularly targeted therapeutics, and immune checkpoint inhibitors with EVs. (iii) Cytotoxic lipids can be also released from tumor cells as RASP. Nevertheless, ex-HSP and EV-HSP can play immunostimulatory and immunosuppressive roles by binding to receptors such as LRP1/CD91/A2MR, scavenger receptors, and toll-like receptors expressed on recipient cells. Liquid biopsy of HSPs in body fluids may be useful in diagnosis, prognosis, and treatment in cancer. Regarding HSP90-targeted therapeutics, we summarize the pros, cons, and problem solutions in this review. Although production of HSPs are canonically induced by heat shock factor 1 (HSF1) and hypoxia-inducible factor 1 (HIF-1), recent studies discovered that production of HSPs is also regulated by matrix metalloproteinase 3 (MMP3) and heterochromatin protein 1 (HP1) and production of cochaperone CDC37 is reciprocally regulated by myeloid zinc finger 1 (MZF1) and SCAN-D1.
REVIEW | doi:10.20944/preprints201912.0386.v1
Subject: Medicine & Pharmacology, Pharmacology & Toxicology Keywords: resistance-associated secretory phenotype (RASP); extracellular vesicle (EV); exosome; oncosome; drug resistance; epithelial-mesenchymal transition (EMT); heat shock protein (HSP); cell stress response; hypoxia; acidosis; tumor immunology
Online: 29 December 2019 (13:46:21 CET)
Extracellular vesicles (EVs), such as exosomes or oncosomes are released with molecules unfavorable for survival from cells. In addition, accumulating evidence has shown that tumor cells often eject anti-cancer drugs such as chemotherapeutics and targeted drugs within EVs, a novel mechanism of drug resistance. The EV-releasing, drug resistance phenotype is often coupled with cellular dedifferentiation and transformation, cells undergoing epithelial-mesenchymal transition (EMT) and taking on a cancer stem cell phenotype. Recent studies have shown that the release of EVs is also involved in immunosuppression. The concept of the resistance-associated secretory phenotype (RASP) is reviewed herein.