A series of studies have revealed that IFN-γ primarily produced by NK- or T-cells can restrict the growth of T. gondii in the acute or chronic phase of infection and that IFN-γ signaling plays a critical role in activating anti-microbial inducible effectors important for the control of intracellular parasites through the transcription factor STAT1 [11,23]. This evidence concerns the gene IFNG and infection.