IFNG and colitis: Colon weight (which correlates with severity of colitis), was also significantly decreased in IL-17A−/−IL-2Rα−/− mice compared to IL-2Rα−/− mice (P = 0.0034), but no significant difference was found in IFN-γ−/−IL-2Rα−/− mice (P = 0.2723) (Figure 4C).