RAG2 and colitis: To demonstrate a role of T-bet+ innate leukocytes in DSS-induced colitis, BALB/c-background Rag2-/- and non-colitic Rag2-/-xTbx21-/- (TRnUC) mice described previously (19) were exposed to 3% or 5% DSS in the drinking water for 5 days (Supplementary Figures 6C, D).