Innate-like lymphocytes emerged as an important plyaers to brigde innate and acquired immunity in a variety of immune reactions as they rapidly exert effector functions in the absence of clonal expansion. They participate the immune-regulation through rapid production of divers cytokines. Invariant natural killer (iNKT) cells and mucosal associated invariant T (MAIT) cells are members of innate-like cells which express invariant T cell receptor a chain paired with a limited set of Vb chanis. These cells are restricted by a nonpolymorphic MHC class 1b molecule, CD1and the MHC-related molecule-1 (MR1), and recognize glycolipid antigens and vitamine metabolites generated by microbiota, respectively. We previously found the regulatory role of MAIT cells in autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS) using MR1 knockout mouse and MAIT-TCR transgenic mouse. We also reported that stimulation of iNKT cells with a synthetic glycolipid prevent disease severity of EAE. We further investigated that MAIT cells and iNKT cells reduced in patients with MS, suggesting the involvement of these cells in the pathogenesis of MS.