Redundant roles of p110γ and p110δ in spontaneous cytotoxicity. Standard chromium release assays with YAC-1 target cells. E/T ratios are based on actual NK- cell numbers as assessed by flow cytometry. (A) WT (●) and p110γ-deficient B6 IL-2–activated NK-cells (). (B) WT (●) and p110δ-deficient (□) B10.D2 IL-2–activated NK cells. Each data point is the mean of triplicates of 1 representative of 3 independent experiments. Error bars represent plus or minus SD (C) WT and p110γ-deficient B6 fresh NK cells were preincubated with the indicated concentrations of p110γ-specific inhibitor AS252424 and then coincubated with target cells at a 5:1 E/T ratio. The dose of 1 μM was chosen for further experiments because the upper dose of 10 μM inhibited cytotoxicity in p110γ-deficient NK cells. Each data point is the mean of 3 independent experiments. Error bars represent plus or minus SD. (D-F) Fresh NK cells of the indicated genotypes were preincubated with media, 10 μM LY294002, or 1 μM AS252424 and then coincubated with target cells at the indicated E/T ratios. LY294002 inhibited cytotoxicity in WT cells, while AS252424 inhibited cytotoxicity only in p110δ-deficient NK cells. Each data point is the mean of 3 independent experiments. Error bars represent plus or minus SD.