IFNG and infection: Finally, because: 1) IFNG is indispensable in the resistance to Toxoplasma gondii [48], 2) Toxoplasma is a master regulator of macrophage signaling pathways [14], and 3) AJ and B6 mice segregate for susceptibility to Toxoplasma [38, 49], we infected non-stimulated or IFNG+TNF-stimulated BMDM with a strain of Toxoplasma engineered to express firefly luciferase [50] and assessed parasite growth by measuring luciferase activity, which is often used to approximate Toxoplasma burden in in vitro or in vivo infection models [49–52].