NOS2 and infection: Contrasting with L. amazonensis infection of BALB/c macrophages that presents lower levels of NOS2, NO, and citrulline [22,23,24], the increased levels of citrulline in C57BL/6-macrophages infected with L. amazonensis compared to uninfected ones support the high levels of NO production by NOS2 and the reduction in infected macrophages in the time-course of infection.