Resting NK-cell degranulation is facilitated by synergy among activation receptors. Resting NK cells were mixed with target cells as indicated. Cells were incubated for 2 hours at 37°C, then stained with fluorochrome-conjugated anti-CD56 and anti-CD107a mAbs. (A) NK cells were gated on forward scatter/side scatter plots, and the profiles show CD56 versus CD107a mAb staining. Gates indicate the percentage of ΔCD107a⁺ NK cells. (B) The percentage of ΔCD107a⁺ NK cells is presented as the mean of 7 donors. Bars indicate SD. **P < .005. (C) The percentage of ΔCD107a⁺ NK cells from 1 representative experiment is shown. Experiments are representative of at least 3 independent experiments.