Several studies have used transgenic mice expressing only the invariant orthologous TRAV1+ (Vα19) chain that defines mouse MAIT cells, to allow the functional characterization of MR1-restricted TRAV1+ T cells in the contexts of T cell development (34, 35), microbial infection (24), and autoimmune diseases (36, 37). The gene discussed is MR1; the disease is autoimmune disease.