Analysis of MAP kinases. NK cells stimulated through their NKRs in the presence or absence of IL-12. (A) Flow cytometry analysis of phospho-ERK or p38 when cells were unstimulated (shaded histogram) or stimulated through Ly49D alone (dotted histogram) or with IL12 (heavy-line histogram). (B) Kinetic changes in phospho-ERK and phopho-p38 in cells stimulated with IL-12 only (▵), with anti-Ly49D (○) alone, or in combination with IL12 (•). (C) IFN-γ production from fresh liver NK cells 16 hours after stimulation with IL-12, NKR, or their combination. Cells were stimulated after no treatment (NT; ▪) or in the presence of the p38 inhibitor (SB203580, ), the ERK inhibitor (U0126, ), or both ().