IFNG and clostridium difficile infection: Consistent with the dominant Th1 cell induction phenotype, we observed a higher level of Ifng gene and IFN-γ protein expression in the colon of CDI + T.mu group compared to the CDI group (Fig. 4C, D), while T.mu did not influence the expression of IL-17A in the colon with or without CDI (Fig. 4E).