Also in the L. major model, it could be shown that two established laboratory strains, L. major Friedlin and L. major MHOM/IL/81/FEBNI, both of Middle Eastern origin, display different infection courses in mice deficient in TNF production (Ritter et al., 2004), indicating that TNF-dependent control of L. major infection is dependent on the parasite strain. This evidence concerns the gene TNF and infection.