NK cells with the highest surface density of Tim-3 degranulate the most when stimulated with target cells. (A) Representative plots depict expression of Tim-3 and surface CD107a in CD56^brightCD16^– (left) and CD56^dimCD16⁺ (right) NK-cell subsets unstimulated (top) or stimulated (bottom) with the human HLA class I–deficient 721.221 target cells. (B) Graphs shows the frequency of CD107a⁺ NK cells based on Tim-3 expression on CD56^brightCD16^– (solid circles) and CD56^dimCD16^– (open circles) NK-cell subsets, after stimulation with 721.221 cells. Experiment performed with cells from 6 unrelated healthy donors. (C) Histograms depict Tim-3 surface expression on CD107a⁻ (gray shade) and CD107a⁺ (black line) cells gated from IL-12– and IL-18–stimulated NK-cell subsets (CD56^brightCD16^– [left] and CD56^dimCD16⁺ [right]) from a representative donor (n = 6).