(A-D) Splenocytes from CD45.2 WT or indicated strain were mixed with CD45.1/2 congenic m157-Tg or WT splenocytes in the presence of the indicated cytokines. IFNβ was used at 100–200 U/ml, IL-12 was used at 10–20 ng/ml, unless otherwise indicated. NK cell GzmB was measured after 16–20 hr incubation. (A) Representative FACS plots are shown on the left and MFI of GzmB in NK cell population of biological duplicates is shown on the right. (B and C) Splenocytes were incubated with the indicated cytokine without stimulator splenocytes. (C) The concentration of the cytokines used were IFNα4 (200 U/ml), IFNβ (200 U/ml), IL-12 (20 ng/ml), IL-2 (200 U/ml), IL-6 (20 ng/ml), IL-15 (20 ng/ml), IL-18 (20 ng/ml). (D) IL-12Rβ2-/- or IFNAR1-/- splenocytes were mixed with cytokine receptor sufficient m157-Tg or control splenocytes. MFI = median fluorescence intensity. (E) Purified NK cells were cultured with m157-Tg or WT control MEF and analyzed as in (A). Data are representative of at least two independent experiments.