Expression of activating KIRs on CD8 T cells. (A) Staining for KIR2DS4 (left) on CD57⁺ CD8 T cells and expression of KIR2DS4 (right) on total CD57⁺ CD8 T cells, KIR2DL1⁻KIR2DL3⁻KIR3DL1⁻CD57⁺ CD8 T cells (no inhibitory KIR), and KIR2DL1^+/−KIR2DL3^+/−KIR3DL1^+/−CD57⁺ CD8 T cells (inhibitory KIR; n = 81; median). (B) Staining for KIR2DS1 (left) on CD57⁺ CD8 T cells and expression of KIR2DS1 (right) on total CD57⁺ CD8 T cells, KIR2DL1⁻KIR2DL3⁻KIR3DL1⁻CD57⁺ CD8 T cells (no inhibitory KIR) and KIR2DL1^+/−KIR2DL3^+/−KIR3DL1^+/−CD57⁺ CD8 T cells (inhibitory KIR). Costaining with antibodies against KIR2DL1 and KIR2DL1/S1 was used for specific identification of KIR2DS1⁺ cells (n = 73; median).