PLC-γ2 is required for NK1.1-initiated, but not for IL-12-initiated, IFN-γ production. WT (▪) and Plcg2^-/- (□) NK cells were stimulated with the indicated stimuli. IFN-γ in the supernatant was quantified 48 hours later. Data are means ± SD of 6 to 8 experiments.