BATF KO mice are deficient with T cells in the intestine. (A) CD4 and CD8 cells in the small intestinal villi of WT and BATF KO mice were examined by immunohistochemistry. Bars, 50 µm. (B) CD4⁺ FoxP3⁻ effector, CD4⁺ FoxP3⁺ regulatory, and CD8⁺ T cells in selected organs were analyzed by flow cytometry. (C) Absolute numbers of each cell population in the indicated organs. Representative (A and B) and pooled (C) data obtained from four experiments using 6–8-wk-old mice are shown. All error bars are SEM obtained from pooled data. Significant differences from WT T cells are shown (*, P < 0.05).