Effect of HLA-specific inhibitory receptors on KIR2DS1-dependent NK-cell activation against allogeneic C2/C2 Bw4/Bw4 mDCs and T cells. Analysis of the cytolytic activity of different groups of KIR2DS1⁺ NK-cell clones (derived from donor P61) against C2/C2 Bw4/Bw4 mDCs (A) or PHA blasts (B) derived from donor RB either in the absence or in the presence of mAb to the indicated molecules. These KIR2DS1⁺ clones coexpressed either NKG2A or KIR3DL1 or KIR2DL2/L3. The E:T ratio used against mDCs was 15:1 whereas that used against PHA blasts was 20:1. Average of 3 independent experiments and SD (mean ± SD) are indicated.