NOS2 and infection: On the other hand, the resistance to infection is associated with Th1 response, with the production of TNF, IL-12 and IFN-γ cytokines and induction of NOS2 expression with consequent NO production resulting in a M1 macrophage functional state, as observed in C57BL/6 mice infection (Ghalib et al., 1995; Vieira et al., 1996; Wilhelm et al., 2001; Yang et al., 2007; Ben-Othman et al., 2009; Srivastava et al., 2012).