Defective population of CD4⁺ T cells in the intestine after intragastric immunization. WT and BATF KO OT-II CD4⁺ T cells were transferred into CD45.1⁺ mice, and the mice were intragastrically immunized with OVA. The mice were sacrificed 12 d later. (A) CD4⁺ CD45.2⁺ T cell subsets in the intestine and other organs were examined by flow cytometry. (B) Absolute numbers of CD4⁺ CD45.2⁺ FoxP3⁺ and FoxP3⁻ CD4⁺ T cells in various organs are shown. Pooled data obtained from three experiments (n = 5–7/group) are shown. All error bars are SEM obtained from pooled data. Significant differences (P < 0.05) from non-OVA–treated groups (*) or WT counterparts (**) are shown.