BALB/c is also highly susceptible to infection by L. major, with severe lesions and parasite-specific Th2 response with the enhanced expression of deactivating macrophage cytokines—particularly interleukin 4 (IL-4), interleukin 10 (IL-10), and transforming growth factor-β (TGF-β) [73]. This evidence concerns the gene IL4 and infection.