Augmentation of natural and antibody-dependent cell-mediated cytotoxicity by pure human leukocyte interferon.

Augmentation of the cytolytic activity of human natural killer cells and of antibody-dependent cell-mediated cytotoxicity has been attributed to human interferons. With the purification to homogeneity of human leukocyte interferon, it became possible to test directly whether pure interferon could increase the activity of these effector cells. Treatment of purified blood mononuclear cells with pure interferon resulted in substantial increases in natural killer cell activity and in antibody-dependent cell-mediated cytotoxicity. Concentrations of 10-100 units/ml of antiviral activity were sufficient to augment appreciably natural killer cell activity.