The burgeoning role of MR1-restricted T-cells in infection, cancer and autoimmune disease.

MR1 is a ubiquitously expressed, monomorphic antigen presenting molecule that has been largely preserved throughout mammalian evolution. The primary role of MR1 is to present conserved microbial metabolites to highly abundant mucosal-associated invariant T (MAIT) cells. The role of MAIT cells and other MR1-restricted T cells (MR1T) has been recently extended to immunomodulation during cancer. MR1Ts have also been implicated in autoimmune disease. The highly conserved nature of MR1 across the human population is in stark contrast to the MHC molecules recognised by conventional αβ T-cells, therefore MR1Ts may form fertile ground for the development of pan-population T-cell immunotherapeutics for a wide range of important morbidities.