The reduction in IL-2 secretion is not seen in IFN-γ−/− and iNOS−/− mice infected with Salmonella. Our findings demonstrate that sustained innate activated IFN-γ production during progression of infection with Salmonella reduces IL-2—secreting capability of T cells through an iNOS-mediated signaling pathway that can adversely affect long term immunity against this pathogen. This evidence concerns the gene NOS2 and infection.