Mucosal-associated invariant T (MAIT) cells are a group of unconventional T cells that are abundant in the human body, recognize microbial-derived vitamin B metabolites presented by MHC class I-related protein 1 (MR1), and rapidly produce proinflammatory cytokines, which are widely involved in the immune response to various infectious diseases. The gene discussed is MR1; the disease is infectious disease.