Acute myocardial infarction (AMI) results from vulnerable plaque rupture, causing ischemic cardiomyocyte necrosis and intense inflammation. Paradoxically, this inflammation releases factors that aid heart repair. Recent findings suggest a role for extracellular vesicles (EVs) in intercellular communication during post-AMI cardiac repair. However, EVs’ tissue origin and chemokine profile in the blood of patients with AMI remains unclear. This study characterized EV tissue origin and chemokine receptor profile in the coronary and peripheral blood of patients with AMI. The results reveal that vesicles isolated from coronary and peripheral blood plasma are enriched in tetraspanin (CD9) and express CD81+, CD90+, and CD144+. The vesicle size ranged between 145 and 162 nm, with the control group exhibiting smaller vesicles than the AMI group. Furthermore, all vesicles expressed CCR6+ and CXCR3+, whereas a small percentage expressed CCR4+. In addition, a decrease in CXCR3+ and CCR6+ positivity was observed in coronary and peripheral blood vesicles compared with the control. Non-difference was found in the coronary and peripheral blood for the CXCR3+ and CCR6+ markers. In conclusion, our study demonstrates, for the first time, changes in the number of extracellular vesicles expressing CD144+, CXCR3+, and CCR6+ in the peripheral circulation of patients with AMI. Extracellular vesicles present in the peripheral circulation of patients with AMI hold excellent promise as a potential diagnostic tool.

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.

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.

Prototypical functions of the chemokine receptor CCR6 include immune regulation by manoeuvring cell chemotaxis and selective delimiting of the pro-inflammatory TH17 and regulatory Treg subsets during chronic or acute systemic inflammation. Inhibition of CCR6 is proposed to attenuate disease symptoms and promote recuperation of multiple inflammatory and autoimmune disorders. Prescription medicines with pharmacodynamics involving the inhibition of the chemokine axis CCR6-CCL20 is very limited. Developing such therapeutics is still at an early experimental stage which has mostly utilized pre-clinical models and neutralizing mono or polyclonal antibodies against either partner, CCR6 or CCL20. Other methods have been constitutive use of small molecules as peptide inhibitors or small interfering ribonucleic acid (siRNA) to interfere with transcription at the nuclear level. We in our review aim at introducing the wide array of potential CCR6-CCL20 inhibitors that have been tried to date in the research field with accent on attendant immune-modulator capacity and which are immensely promising compounds as forerunners of future curatives. 16 different tractable inhibitors of the CCR6-CCL20 duo have been identified to possess high medicinal potential to the drug developers worldwide to treat autoimmune and inflammatory diseases. A multitude of antibody preparations are already available in the current pharmaceutical market as patented treatment for diseases in which the CCR6-CCL20 axis is operative, yet must be used only as supplements with existing routinely prescribed medication as they collectively produce adverse side effects. Novel inhibitors are needed to evaluate this invaluable therapeutic target which holds much promise in the research and development of complaisant remedies for inflammatory diseases.

Inflammatory bowel disease (IBD) has evoked a significant interest in human immunobiology given its tactical immune evasion methodologies resulting in acute immune destabilization. IBD comprising of Crohn’s disease and Ulcerative colitis manifest as chronic inflammation in the gut mucosa, leading to complexities involving immune dysregulation in the T helper lymphocyte arm effecting disease pathogenicity. The mucosa of the alimentary canal is constantly exposed to a myriad of food antigens and luminal microorganisms for which a consistent host-protective mechanism is operative in healthy people. Lowered mucosal immune expression which allows penetration of the epithelial barrier by infective pathogenic microbes, elicits both innate and adaptive immune responses in the gut culminating in aberrant intestinal inflammation. Interestingly, IBD leukocyte repertoire is significantly entwined with chemokine assisted chemotactic navigation into the sites of inflammation which is also thought to generate favourable immune suppressive responses. The functions of the cognate chemokine receptor, CCR6, which binds with its unique ligand CCL20, are expected to tilt the balance between upregulation of homeostatic tolerance and inflammatory pathophysiology. This review aims at critically examining the CCR6 driven immune pathways; T_H1/T_H2, T_H1/T_H17, T_H17/ T_reg, IL-23/IL-17, Akt/ERK-1 /2, ILC3 for systematic investigation of its underlying mechanisms in the future and to underpin its importance in resolving IBD aetiopathology. Thus, CCR6 occupies an exclusive position in gut immunology which renders it an invaluable therapeutic tool for the production of novel medicaments to treat IBD.

Chemokine C-C receptor 6 (CCR6) and its exclusive ligand CCL20 is an extremely important chemokine receptor-ligand pair which controls cell migration and immune induction during inflammatory disease. Not many scientific studies have been undertaken to study its immune mechanisms in detail, but its unique contribution to steady state cell chemotaxis in upholding immune tolerance and regulating immune homeostasis during inflammation is evident in multiple organ systems, including lung, liver, kidney, skin, brain, eye, joints, gonads and the gut in the human body. The role of CCR6 is constitutively expressed as a series of much debilitating severe inflammatory and autoimmune diseases, HIV and cancer metastasis. CD4⁺ T cells, the central organizers of adaptive immunity, are stringently mobilized by the CCR6/CCL20 axis also induced by cytokines and a host of other factors in a carefully executed immune modulation scenario, to bring about a delicate balance between pro-inflammatory T_H17 cells and regulatory T_reg cells. Although the exact immune regulatory role is not elucidated yet, CCR6/CCL20 axis is implicated as a front runner which determines the polarization of T_H17 and T_reg cells and consequently the resolution or progression of many debilitating disorders. This review therefore aims at emphasizing the pleiotropic significance of the chemokines CCR6 and CCL20 in immunologic function in multiple organ systems thereby hoping to accentuate its value in future therapeutic modalities.

The immunomodulatory behaviour of the CCR6/CCL20 axis in multi -system pathophysiology and molecular signalling was investigated at two clinically significant time points, using a Ccr6 - deficient mouse model of spontaneous colitis. Four groups of mice, (C57BL/6J, Ccr6^-/- of C57BL/6J, Winnie x Ccr6 ^-/- and Winnie) were utilized and (I) colonic clinical parameters (2) histology of colon, spleen, kidney and liver (3) T and B lymphocyte distribution in the spleen and MLN by flowcytometry (5) colonic CCL20, phosphorylated PI3K and phosphorylated Akt expression by immunohistochemistry and (6) colonic cytokine expression by RT-PCR were evaluated. CCR6 deficiency was shown to attenuate inflammation in the spleen, liver and gut while renal histology remained unaffected. Marked focal lobular inflammation with reactive nuclear features were observed in hepatocytes and a significant neutrophil infiltration in red pulp with extra medullary hemopoiesis in the spleen existed in Winnie. These changes were considerably reduced in Winnie x Ccr6^-/- with elevated goblet cell numbers and mucus production in the colonic epithelium. Results indicate that Ccr6- deficiency in the colitis model contributes towards resolution of disease. Our findings demonstrate an intricate networking role for CCR6 in immune activation, which is downregulated by Ccr6 deficiency, and could provide newer clinical therapies in colitis.

Inflammatory bowel disease (IBD) is a CC chemokine receptor 6 (CCR6) - associated immune mediated disorder which has attracted an extensive superfluity of experimental analyses. IBD has come to the fore of varied scrutinizing owing to its complexity by nature for comprising of two synergistic sub phenotypes; Crohn’s disease (CD) and Ulcerative colitis (UC). Both these disease entities cause potent immune dysregulation followed by intense tissue damage within the gut mucosal system, initiating symptoms which are severely debilitating. Multiple causative factors are said to be responsible for IBD but direct immune dysfunction is kindled by overplay of innate and adaptive immune responses produced against a pathogenic microbial attack through the weakened or leaky gut epithelial barrier. Once immune homeostasis is not achieved by tolerating agents, the self-assertive adaptive immunity mobilize its various T and B cell cohorts initializing their allied immune mechanisms by vigorously deploying them towards the site of infection. CCR6 and its unique solitary ligand CC-chemokine ligand 20 (CCL20) are small protein molecules which are abundantly expressed by T and B lymphocytes and act as chemotactic immune-modulatory envoys that help in the deployment of the effector lymphocyte arm of the immune system, producing two directly opposing outcomes in IBD. This dichotomous immunity consists of either immune tolerance or inflammation which then develops into a chronic state, remaining catatonic to inherent immunity or targeted clinical therapy. In this review, we have chronologically identified a plethora of experimental studies radiating into 14 different compartments highlighted in the visual depiction which have employed both mouse models and clinical subjects spanning a period of nearly two decades. In doing so, we expect the research community would further benefit by tracing through the history, thereby understanding the CCR6 –CCL20 axis in IBD and identifying the gaps in literature which can be fortuitously filled in the future.