IFNG and infection: Although a protective role against intracellular bacteria such as Listeria monocytogenes [55] or S. typhimurium (N. Y. A. Hemdan and A. M. Abu El-Saad, unpublished data) may be attributed to TH17 response, this may be rather compensatory to a defective IL-12/IFN-γ axis as previously demonstrated by N. N. Orgun et al. [56], or a complementary function to indirectly induce type 1 response mediated by APCs endowing thereby a protection against infection, as in case of the obligate intracellular bacteria Chlamydia muridarum [57].