Figure 1.

Effect of MR1 deficiency on oxazolone-induced colitis. Oxazolone-induced colitis was induced in MR1^−/− (n = 32) and littermate WT control mice (n = 30). Survival rate (A) and percent of body weight from day 0 (B) are shown after the intrarectal administration of oxazolone. (C-E) DAI, colon length, and histologic score at sacrifice are shown. (F) Representative pictures of hematoxylin and eosin-stained sections of colon from MR1^−/− and WT mice. (Scale bars, 100 μm). (G-I) Flow cytometric evaluation of the frequencies of total MAIT cells, CD69⁺ cells among MAIT cells and RORγt⁺ cells among MAIT cells 24 hours after oxazolone (oxa) or control (ctrl) administration intrarectally (n = 8). (G) LPL were gated on using a forward scatter area (FSC-A) versus side scatter area (SSC-A) plot. Single cells were selected by using FSC-A versus FSC-width (FSC-W) and SSC-A versus SSC-width (SSC-W) plots. Zombie green positive dead cells and F4/80 positive cells were excluded to gate out cells that had bound to antibodies and tetramers non-specifically. MAIT cells were identified as CD3⁺ MR1/5-OP-RU tetramer⁺ cells. (H) Representative flow cytometry profiles of CD69-stained MAIT cells are shown. Significance was determined using the Log-rank (Mantel-Cox) test (A) and Welch’s t-test (B-E, G-I). ∗P < .05. Data are represented as the mean ± standard error of the mean in each group. Each symbol represents data from an individual mouse.