Uncontrolled IFN-γ production in perforin^−/−DC-Fas^−/− mice. (A) Sera from 4-week-old WT, perforin^−/− (Perf^−/−), DC-Fas^−/−, and Perf^−/−DC-Fas^−/− mice were used for the measurement of different cytokines by multiplex. WT versus Perf^−/−DC-Fas^−/−: IFN-γ, ** P < .01; IP-10, *P < .05; other cytokines, not significant. (B) Intracellular staining for IFN-γ in CD8⁺ T cells and DX5α⁺ NK cells. Mean fluorescence intensity (MFI) for IFN-γ staining: **P < .01.