Figure 4. Epithelial MHCII regulates commensal-specific T cells.

(A and B) Number of cBir1⁺-specific CD4⁺ T cells in large intestine of MHCII^FF and MHCII^ΔIEC mice. (C and D) Frequency of FoxP3⁺ (C) and RORγt⁺ (D) cBir1⁺ CD4⁺ T cells in large intestine of MHCII^FF and MHCII^ΔIEC mice. (E) Diagram of 2W1S–Candida albicans commensal colonization. (F) Number of C. albicans–2W1S⁺–specific CD4⁺ cells in large intestine of MHCII^FF and MHCII^ΔIEC mice. (G) Diagram of 2W1S peptide feeding model. (H) Number of 2W1S⁺-specific CD4⁺ cells in large intestine of MHCII^FF and MHCII^ΔIEC mice. (I) Frequency of rectal prolapse in MHCII^FF and MHCII^ΔIEC mice. (J) H&E-stained colonic sections of MHCII^FF and prolapsed MHCII^ΔIEC mice (MHCII^ΔIEC*). Scale bars: 20 μM. (K and L) Frequency of myeloid cell infiltrate (K) and lipocalin-2 levels (L) in stool of MHCII^FF and MHCII^ΔIEC*. (M–O) Number of cBir1⁺-specific CD4⁺ T cells (M) and frequency of FoxP3⁺ (N) and RORγt⁺ (O) cBir1-specific T cells in large intestine of control and prolapsed MHCII^ΔIEC and HDAC3^ΔIEC mice. Tetramer cells are gated on live, CD45⁺, lineage (CD11b^–B220^–Ly6G^–, CD11c^–CD8a^–), CD4⁺. Data are representative of at least 2 independent experiments (A–H) or are pooled from at least 2 independent experiments (I–O), 3–6 mice per group. *P < 0.05, **P < 0.01, ***P < 0.001, by unpaired 2-tailed Student’s t test (B–H and L–O) or Mantel-Cox test (I).