RAG1 and Chronic colitis: Chronic colitis was induced in Rag1 KO mice by passive transfer with CD45RBhiCD4+CD25– naïve T cells from C57BL/6J mice exhibiting severe body weight loss (Figure 8A), loss of crypts in the colonic mucosa, infiltration of inflammatory cells (Figure 8B), and higher levels of IL-17A and IFN-γ production by LPMCs (Figure 8C).