Isolation and Characterization of MAIT Cells from Human Tissue Biopsies

Human mucosal-associated invariant T (MAIT) cells are unconventional T cells highly enriched in tissues exposed to microbial antigens including the oral, gastrointestinal and genital mucosae, liver, and lung. Here we describe a protocol for isolation and characterization of peripheral blood and tissue-infiltrating MAIT cells by using multicolor flow cytometry. This technology allows the analysis of multiple markers in a single sample at a single-cell level. Study of human samples requires particular care since the sample amount is often limited. We present a protocol optimized for the isolation and characterization of human MAIT cells and the identification of MAIT cell populations detected by simultaneous expression of multiple activation markers and inhibitory receptors.