IFN-γ is believed to play diverse roles in infectious diseases, including the activation and polarization of CD4+ Th cells, upregulation of Fas in infected target cells, upregulation of MHC I and II-restricted Ag-presentation pathways, macrophage activation, and direct antiviral activity that overlaps with activities triggered by IFN-I [68]. The gene discussed is IFNG; the disease is infectious disease.