Figure 1.

Human purified NK cells incubated with IL-2 increase cytotoxic activity. NK cells were incubated for 48 or 72 h in the presence of 50 IU/mL (control) (black bar) or with 2000 IU/mL to induce LAK activity (grey bar). Cytotoxic activity was measured in a 4 h ⁵¹Cr release assay using Daudi cells as target cells and an effector : target ratio of 1 : 1. Results are mean ± SE from at least 8 independent experiments (^∗ p < 0.05).