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

Background/Aims: 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 V alpha 7.2-J alpha 33 (human)/V alpha 19-J alpha 33 (mice) invariant chain. The encoding DNA sequences of Human J alpha 33 and mouse J alpha 33 are identical. In order to study the role of MAIT cells in IBD we produced anti-J alpha 33 antibody to detect MAIT cells in TNBS induced IBD models. Methodology: Colitis was induced by TNBS in male BALB/c mice. J alpha 33(+)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 J alpha 33(+)MAIT cells. Results: The mRNA and protein expression levels of MAIT aTCR in the colonic mucosa were decreased after TNBS administration; J alpha 33(+)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 J alpha 33(+)MAIT cells significantly degrade the increase in the disease activity index scores. Conclusions: Taken together, the results indicated that the aggregation of J alpha 33(+)MAIT cells in intestinal mucosa improved TNBS-induced colitis. We conclude that J alpha 33(+)MAIT cells play a protective role in TNBS induced intestinal inflammation.