Killing of allogeneic C2/C2, Bw4/Bw6 target cells by KIR3DL1⁺ KIR2DS1⁺ NK-cell clones. (A) Killing by KIR3DL1⁺ KIR2DS1⁺ or KIR3DL1⁺ KIR2DS1⁻ NK-cell clones (derived from donor P61) against mDCs and PHA blasts (derived from the C2/C2 Bw4/Bw6 donor GF) was analyzed either in the absence or in the presence of mAb to the indicated molecules. 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. (B) Representative KIR3DL1⁺KIR2DS1⁺ and KIR3DL1⁺KIR2DS1⁻ NK-cell clones (derived from donor P61) were analyzed by cytofluorimetric analysis for the expression of the indicated molecules (black profiles). White profiles refer to cells incubated with the second reagent only. The MFI is indicated.