Involvement of PKC-θ in the costimulatory effect of KIR2DL1 in human T cells. (A) Jurkat, EV, and JK32 cells were stimulated with mAb for 15 minutes. Cell lysates were analyzed by immunoblotting with mAbs against p-PKC-θ, PKC-θ, and actin. (B) Confocal microscopic analysis of the distribution of p-PKC-θ and KIR2DL1 in EV and JK32 cells conjugated with SEE-pulsed 721.221/HLA-Cw7 or 721.221/HLA-Cw4 cells. The distribution of p-PKC-θ (in red) was analyzed as in Figure 4. KIR2DL1 appears as green fluorescence. (C) Cells were treated as described in panel B, and images of 5 fields were visualized with a 63×/1.4 oil-immersion objective. Signal intensity was quantified with ImageJ software.