IFNG and bacterial infectious disease: In conclusion, in several bacterial infections requiring strong IFN-γ responses for protection, type I IFN appears to be detrimental, and at least 3 separate, but overlapping, type I IFN-mediated mechanisms are involved: induction of excessive apoptosis, specific suppression of Th1 and IFN-γ responses or of IL-1β required for bacterial control, and dampening of the immune response by strong IL-10 induction.