IFNG and infection: The M1 polarization is important for the control of infection by Leishmania spp. They are characterized by the impaired tricarboxylic cycle (TCA cycle), production of pro-inflammatory cytokines such as Interleukin-12 (IL-12), interferon gamma (IFNγ) and by generation of reactive oxygen species (ROS) and nitric oxide (NO) that help in efficient parasite killing.