Cytotoxicity assay in the presence of IL-2.

IL-2 enhanced the killing of target cells by NK cells, whereas IL-2 abolished or decreased the difference in the cytotoxicity betweenPIG-A mutant and control cells. Peripheral NK cells obtained from 3 healthy volunteers (A-C) were cocultured for 3 hours with K562 cells with (▪) and without (■) PIG-A mutation in the absence or the presence of 10 ng/mL IL-2. E/T ratio was 32:1. Each value represents the mean (± SD) of triplicate assays. *Statistical significance (P < .05).