Jα33+ MAIT cells play a protective role in TNBS induced intestinal inflammation.

Abstract Mucosa-associated T-lymphocyte (MAIT) cells that are selectively accumulated in the intestinal mucosa may be involved in immune regulation. MAIT cells are determined by their Vα7.2-Jα33 (human)/Vα19-Jα33 (mice) invariant chain. The encoding DNA sequences of Human Jα33 and mouse Jα33 are identical. In order to study the role of MAIT cells in IBD we produced anti-Jα33 antibody to detect MAIT cells in TNBS induced IBD models. Colitis was induced by TNBS in male BALB/c mice. Jα33+MAIT cells from normal mice were transferred into TNBS induced mice as donors. Colitis severity was evaluated clinically and histologically, under the condition of transferred Jα33+MAIT cells. The mRNA and protein expression levels of MAIT aTCR in the colonic mucosa were decreased after TNBS administration; Jα33+MAIT cells were aggregated in spleen after TNBS administration. The disease activity index (DAI) which was determined by weight loss, stool consistency and intestinal bleeding, increased after TNBS administration. Transferred Jα33+MAIT cells significantly degrade the increase in the disease activity index scores. Taken together, the results indicated that the aggregation of Jα33+MAIT cells in intestinal mucosa improved TNBS-induced colitis. We conclude that Jα33+MAIT cells play a protective role in TNBS induced intestinal inflammation.