KM871-mediated ADCC activity of PBMCs cultured in the presence of cytokine combinations. PBMCs (2.5 x 10⁵/well) were cultured for 1 to 10 days at 37°C with (A) IL-2 (10 ng/ml) and IL-12 (100 ng/ml), (B) IL-12 (100 ng/ml) and GM-CSF (500 ng/ml), (C) IL-2 (10 ng/ml) and GM-CSF (500 ng/ml), or (D) IL-2 (10 ng/ml) plus IL-12 (100 ng/ml) and GM-CSF (500 ng/ml). ADCC activities were determined on days 1, 2, 3, 5, 7 and 10 at an E:T ratio of 25:1 and with 1 µg/ml KM871 mAb (open bars). Control mAb KM966 (//) and medium only (\\) were included. The data, expressed as the mean % cytotoxicity of triplicate samples with error bars denoting standard deviation, is representative of over 3 experiments conducted.