RAG1 and colitis: In contrast to Rag1–/– recipients that received CD4+ T cells from control mice, Rag1–/– recipients receiving CD4+ T cells from HDAC3ΔIEC mice displayed more significant weight loss (Figure 2B), colonic shortening (Figure 2C), and severe colitis pathology characterized by inflammatory cell infiltration, crypt hyperplasia, and mural thickening (Figure 2, D and E).