Mucosa-Associated Invariant T Cell Roles And Local Responses In Cell-Mediated Immunity To Influenza A Virus

Mucosa-associated invariant T (MAIT) cells are innate-like T cells that are activated by microbial vitamin B metabolites and/or cytokine stimulation to produce pro-inflammatory cytokines and cytotoxic granules. Influenza A viruses (IAVs) activate MAIT cells in a by-stander manner, and their abundance negatively correlates with infection-induced morbidity and mortality. However, how MAIT cells directly contribute to anti-viral immunity is ill-defined. I hypothesized that MAIT cells’ presence in mice enhances antigen-specific CD8+ T cell responses. I observed a trend that MAIT cell-deficient mice generally developed smaller populations of antigen-specific CD8+ T cells following IAV exposure than mice abundant in MAIT cells, with this difference being pronounced amongst female mice. Co-administration of IAV and a potent MAIT cell ligand did not influence the anti-IAV CD8+ T cell response, but induced rapid MAIT cell accumulation in the peritoneal cavity. These results indicate that MAIT cells are poised to influence anti-viral adaptive immune responses