Circulating mucosal-associated invariant T cells identify patients responding to anti-PD-1 therapy.
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ABSTRACT:
SUBMITTER: De Biasi S
PROVIDER: S-EPMC7961017 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectivesWhile much of the research concerning factors associated with responses to immune checkpoint inhibitors (ICIs) has focussed on the contributions of conventional peptide-specific T cells, the role of unconventional T cells, such as mucosal-associated invariant T (MAIT) cells, in human melanoma remains largely unknown. MAIT cells are an abundant population of innate-like T cells expressing a semi-invariant T-cell receptor restricted to the MHC class I-like molecule, MR1, presenting vitamin B metabolites derived from bacteria. We sought to characterise MAIT cells in melanoma patients and determined their association with treatment responses and clinical outcomes.MethodsIn this prospective clinical study, we analysed the frequency and functional profile of circulating and tumor-infiltrating MAIT cells in human melanoma patients. Using flow cytometry, we compared these across metastatic sites and between ICI responders vs. non-responders as well as healthy donors.ResultsWe identified tumor-infiltrating MAIT cells in melanomas across metastatic sites and found that the number of circulating MAIT cells is reduced in melanoma patients compared to healthy donors. However, circulating MAIT cell frequencies are restored by ICI treatment in responding patients, correlating with treatment responses, in which patients with high frequencies of MAIT cells exhibited significantly improved overall survival.ConclusionOur results suggest that MAIT cells may be a potential predictive marker of responses to immunotherapies and provide rationale for testing MAIT cell-directed therapies in combination with current and next-generation ICIs.
| S-EPMC8743567 | biostudies-literature
Project description:Mucosal-associated invariant T (MAIT) cells are an antimicrobial MR1-restricted T cell subset and play an important role in immune defense response to bacteria. However, little is known about the role of MAIT cells in cancer. The aims of this study were to examine the level and function of MAIT cells in cancer patients and to evaluate the clinical relevance of MAIT cell levels. Ninety-nine patients with cancer and 20 healthy controls were included in this study. Circulating MAIT cell levels were significantly reduced in patients with mucosal-associated cancers (MACs), such as gastric, colon and lung cancers, but their capacities for IFN-?, IL-17, or TNF-? production were preserved. This MAIT cell deficiency was significantly correlated with N staging and carcinoembryonic antigen level. Percentages of MAIT cells were significantly higher in cancer tissue than in peripheral blood and immunofluorescent labeling showed MAIT cell infiltration into colon cancer tissues. Circulating MAIT cells exhibited high levels of CCR6 and CXCR6, and their corresponding chemokines, such as CCL20 and CXCL16, were strongly expressed in colon cancer tissues. Activated MAIT cells not only had lymphokine-activated killer activity, but they also had direct cytotoxicity on K562 cells via degranulation of granzyme B and perforin. This study primarily demonstrates that circulating MAIT cells are reduced in MAC patients due to migration to mucosal cancer tissues and they have the potential to kill cancer cells. In addition, this circulating MAIT cell deficiency is related to the degree of cancer progression in mucosal tissues.
| S-EPMC5342813 | biostudies-other
Project description:ObjectivesMucosal-associated invariant T (MAIT) cells have been shown to contribute in the pathogenesis of various liver diseases, including chronic hepatitis C virus (HCV) infection. This study was aimed at investigating the frequency, phenotype, and function of circulating MAIT cells, as well as their alterations after successful direct-acting antivirals (DAAs) in HCV-infected patients with or without HIV infection.MethodsA total 85 patients (51 HCV-monoinfection and 34 HCV/HIV-coinfection), who received elbasvir/grazoprevir from a clinical trial and 20 healthy controls were included. MAIT cells in blood were characterized using flow cytometry at baseline and 24 weeks post-treatment.ResultsHCV-monoinfected and HCV/HIV-coinfected patients achieved similar sustained virological response rates (SVR24, 94.1% vs. 97.1%). Circulating MAIT cells in the monoinfection and coinfection groups were presented at low frequencies in comparison with healthy controls (median, 1.1% vs. 1.1% vs. 2.4%, P<0.001) and exhibited features of chronic activation and impaired functional capacity. A negative correlation between circulating MAIT cell frequency and liver stiffness assessed by magnetic resonance elastography was observed. Compared with baseline, increased in circulating MAIT cells after successful DAA therapy was mainly detected in HCV-monoinfected patients compared with HCV/HIV-coinfected individuals. Moreover, MAIT cell restoration was predominantly observed among patients with significant fibrosis to cirrhosis (F2-F4).ConclusionsThese data indicated that dysregulation of MAIT cells might play a role in the progression of chronic HCV infection. Partial restoration of MAIT cell frequency and function was observed after successful DAA therapy, particularly in HCV-monoinfected patients.
| S-EPMC7775079 | biostudies-literature
Project description:Mucosal associated invariant T (MAIT) cells are important for immune defense against infectious pathogens and regulate the pathogenesis of various inflammatory diseases. However, their roles in the development of colorectal cancer (CRC) are still unclear. This study examined the phenotype, distribution, clinical relevance and potential function of MAIT cells in CRC patients. We found that the percentages of circulating memory CD8(+) MAIT cells were significantly reduced while tumor infiltrating MAIT cells were increased, especially in patients with advanced CRC. The serum CEA levels were positively correlated with the percentages of tumor infiltrating MAIT cells in CRC patients, but negatively correlated with the percentages of circulating MAIT in advanced CRC patients. Activated circulating MAIT cells from CRC patients produced lower IFN-?, but higher IL-17. Furthermore, higher levels of V?7.2-J?33, IFN-? and IL-17A were expressed in the CRC tissues. Co-culture of activated MAIT cells with HCT116 cells enhanced IL-17 expression and induced HCT116 cell cycle arrest at G2/M phase in a contact- and dose-dependent manner, which was abrogated by treatment with anti-MR1. Therefore, MAIT cells preferably infiltrate into the solid tumor in CRC patients and may participate in the immune surveillance of CRC.
| S-EPMC4738248 | biostudies-other
Project description:BackgroundUrinary tract infection recurrence is common, particularly in women and immunocompromised patients, such as renal transplant recipients (RTRs). Mucosal-associated invariant T (MAIT) cells play a role in the antibacterial response by recognizing bacterial riboflavin metabolites produced by bacteria such as Escherichia coli. Here, we investigated whether MAIT cells are involved in the pathogenesis of recurrent urinary tract infections (RUTIs).MethodsUsing multichannel flow cytometry, we characterized the MAIT cell phenotype and function in blood from immunocompetent adults with (n = 13) and without RUTIs (n = 10) and in RTRs with (n = 9) and without RUTIs (n = 10).ResultsThere were no differences in the numbers of MAIT cells between the study groups. MAIT cells in patients with RUTI expressed T-bet more often than those in controls. MAIT cells from immunocompetent RUTI participants required more antigen-presenting cells coincubated with E. coli to evoke a similar cytokine and degranulation response than those from controls. This effect was absent in the RTR with RUTI vs RTR control groups, where the overall percentage of MAIT cells that responded to stimulation was already reduced.ConclusionCirculating MAIT cells in immunocompetent individuals with RUTIs respond to bacterial stimuli with reduced efficacy, which suggests that they are involved in the pathogenesis of RUTIs.
| S-EPMC7016840 | biostudies-literature
Project description:Human mucosal-associated invariant T (MAIT) cells are characterized by their expression of an invariant TCR α chain Vα7.2-Jα33/Jα20/Jα12 paired with a restricted TCR β chain. MAIT cells recognize microbial peptides presented by the highly conserved MHC class I-like molecule MR1 and bridge the innate and acquired immune systems to mediate augmented immune responses. Upon activation, MAIT cells rapidly proliferate, produce a variety of cytokines and cytotoxic molecules, and trigger efficient antitumor immunity. Administration of a representative MAIT cell ligand 5-OP-RU effectively activates MAIT cells and enhances their antitumor capacity. In this review, we introduce MAIT cell biology and their importance in antitumor immunity, summarize the current development of peripheral blood mononuclear cell-derived and stem cell-derived MAIT cell products for cancer treatment, and discuss the potential of genetic engineering of MAIT cells for off-the-shelf cancer immunotherapy.
| S-EPMC10014234 | biostudies-literature
Project description:Over the past decade, we have contributed to the chemistry of microbial natural products and synthetic ligands, related to riboflavin and uracils, that modulate immune cells called mucosal associated invariant T cells (MAIT cells). These highly abundant T lymphocytes were only discovered in 2003 and have become recognized for their importance in mammalian immunology. Unlike other T cells, MAIT cells are not activated by peptide or lipid antigens. In collaboration with immunology and structural biology research groups, we discovered that they are instead activated by unstable nitrogen-containing heterocycles synthesized by bacteria. The most potent naturally occurring activating compound (antigen) is 5-(2-oxopropylideneamino)-d-ribitylaminouracil (5-OP-RU). This compound is an imine (Schiff base) formed through condensation between an intermediate in the biosynthesis of riboflavin (vitamin B2) and a metabolic byproduct of mammalian and microbial glycolysis. Although it is very unstable in water due to intramolecular ring closure or hydrolysis, we were able to develop a non-enzymatic synthesis that yields a pure kinetically stable compound in a nonaqueous solvent. This compound has revolutionized the study of MAIT cell immunology due to its potent activation (EC50 = 2 pM) of MAIT cells and its development into immunological reagents for detecting and characterizing MAIT cells in tissues. MAIT cells are now linked to key physiological processes and disease, including antibacterial defense, tissue repair, regulation of graft-vs-host disease, gastritis, inflammatory bowel diseases, and cancer. 5-OP-RU activates MAIT cells and, like a vaccine, has been shown to protect mice from bacterial infections and cancers. Mechanistic studies on the binding of 5-OP-RU to its dual protein targets, the major histocompatibility complex class I related protein (MR1) and the MAIT cell receptor (MAIT TCR), have involved synthetic chemistry, 2D 1H NMR spectroscopy, mass spectrometry, computer modeling and molecular dynamics simulations, biochemical, cellular, and immunological assays, and protein structural biology. These combined studies have revealed structural influences for 5-OP-RU in solution on protein binding and antigen presentation and potency; informed the development of potent (EC50 = 2 nM) and water stable analogues; led to fluorescent analogues for detecting and tracking binding proteins in and on cells; and enabled discovery of drugs and drug-like molecules that bind MR1 and modulate MAIT cell function. MAIT cells offer new opportunities for chemical synthesis to enhance the stability, potency, selectivity, and bioavailability of small molecule ligands for MR1 or MAIT TCR proteins, and to contribute to the understanding of T cell immunity and the development of prospective new immunomodulating medicines.
| S-EPMC8989627 | biostudies-literature
Project description:Conventional T cells exhibit a delayed response to the initial priming of peptide antigens presented by major histocompatibility complex (MHC) proteins. Unlike conventional T cells, mucosal-associated invariant T (MAIT) cells quickly respond to non-peptidic metabolite antigens presented by MHC-related protein 1 (MR1). To elucidate the MR1-dependent activation program of MAIT cells in response to mycobacterial infections, we determined the surface markers, transcriptomic profiles, and effector responses of activated human MAIT cells. Results revealed that mycobacterial-incubated antigen-presenting cells stimulated abundant human CD8+ MAIT cells to upregulate the co-expression of CD69 and CD26, as a combinatorial activation marker. Further transcriptomic analyses demonstrated that CD69+CD26++ CD8+MAIT cells highly expressed numerous genes for mediating anti-mycobacterial immune responses, including pro-inflammatory cytokines, cytolytic molecules, NK cell receptors, and transcription factors, in contrast to inactivated counterparts CD69+/-CD26+/- CD8+MAIT cells. Gene co-expression, enrichment, and pathway analyses yielded high statistical significance to strongly support that activated CD8+ MAIT cells shared gene expression and numerous pathways with NK and CD8+ T cells in activation, cytokine production, cytokine signaling, and effector functions. Flow cytometry detected that activated CD8+MAIT cells produced TNFα, IFNγ, and granulysin to inhibit mycobacterial growth and fight mycobacterial infection. Together, results strongly support that the combinatorial activation marker CD69+CD26++ labels the activated CD8+MAIT cells that develop an innate-like activation program in anti-mycobacterial immune responses. We speculate that the rapid production of anti-mycobacterial effector molecules facilitates MAIT cells to fight early mycobacterial infection in humans.
| S-EPMC7295940 | biostudies-literature
Project description:BackgroundMucosal Associated Invariant T (MAIT) cells are innate-like T cells found in abundance in the intestinal mucosa, and are thought to play a role in bridging the innate-adaptive interface.MethodsWe measured MAIT cell frequencies and antibody responses in blood from patients presenting with culture-confirmed severe cholera to a hospital in Dhaka, Bangladesh at days 2, 7, 30, and 90 of illness.ResultsWe found that MAIT (CD3+CD4-CD161hiVα7.2+) cells were maximally activated at day 7 after onset of cholera. In adult patients, MAIT frequencies did not change over time, whereas in child patients, MAITs were significantly decreased at day 7, and this decrease persisted to day 90. Fold changes in MAIT frequency correlated with increases in LPS IgA and IgG, but not LPS IgM nor antibody responses to cholera toxin B subunit.ConclusionsIn the acute phase of cholera, MAIT cells are activated, depleted from the periphery, and as part of the innate response against V. cholerae infection, are possibly involved in mechanisms underlying class switching of antibody responses to T cell-independent antigens.
| S-EPMC4140671 | biostudies-literature
Project description: Not available
| S-EPMC7214121 | biostudies-literature