NOS2 and infection: As demonstrated in Fig 3, when the iNOS gene was ablated in rats, it developed a pro-inflammatory immune environment and Th1 immune deviation, with an increase in pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6, P<0.05) (Fig 3A) and in Th1 cytokines (IFN-γ, P<0.05) (Fig 3B) in naïve KO rats in comparison with naïve WT rats (0 w post-infection).