IFNG and viral infectious disease: Responses were measured by intracellular cytokine staining (ICS) and polychromatic flow cytometry for cytokines associated with effective control of viral infections: IFNγ, tumor necrosis factor (TNF) and interleukin 2 (IL-2), and for a cytokine associated with poor control of viral infections [25]–[27], interleukin 10 (IL-10).