IL17A and colitis: While induction of transfer colitis in Ifnγ-sufficient mice (Ifng+/+ CD4 T cells → Rag1−/−Ifng+/+ mice) resulted in elevated expression of the Ifnγ-associated genes Cxcl9 and Cxcl10 in the colon (Figure 4), absence of IFNγ (Ifng−/− CD4 T cells → Rag1−/−Ifng−/− mice) significantly favored the expression of Th17 related genes including Il17a, Il17f, Il22, Ccl20, and Rorgt (Figure 4).