The OF-5A12 monoclonal antibody specifically recognizes the human variable alpha 7.2 region of the T cell receptor for antigen (TCR Vα7.2) that is joined with the Jα33 segment to form an invariant TCR which is characteristically expressed by mucosal-associated invariant T cells (MAIT cells). MAIT cell recognition of antigen is restricted by MHC-related molecule 1 (MR1), a nonpolymorphic Class Ib Major Histocompatibility Complex (MHC) molecule, that associates with β2-microglobulin. MAIT cells are found in human peripheral blood, mesenteric lymph nodes, liver, and mucosa associated with the lungs and intestines. MAIT cells play a role in detecting and fighting off microbial infections. The specificity of OF-5A12 for the TCR Vα7.2 was confirmed by its ability to block the binding of another human TCR Vα7.2-specific antibody, 3C10, to MAIT cells.