Works using mouse models, intent to elucidate immune events important for Leishmania killing, have revealed that reactive oxygen species produced by IFN-γ-activated mononuclear phagocytes, is the main mechanism used by infected macrophages to destroy Leishmania. Thus, while in BALB/c mice infected with L. major Th2 immune response prevails allowing parasites to multiplicate, C57BL/6 mice are able to control infection with strong Th1 immune response. Here, IFNG is linked to infection.