The IL-2 has been shown to promote the survival of Mtb-specific T cells and the development of immune memory (17); IFN-γ has been demonstrated to induce the production of antimicrobial molecules by macrophages, including oxygen free radicals and nitric oxide (18); TNF-α has been observed to stimulate the migration of effector cells to the site of infection and to induce the production of reactive nitrogen intermediates, which act in synergy with IFN-γ to reduce bacterial burden of Mtb (18). Here, IFNG is linked to infection.