Interferon enhances antibody-dependent cellular cytotoxicity when suboptimal concentrations of antibody are used.

Polymorphonuclear leukocytes (PMN) and killer (K) cells isolated from buffy coats from normal volunteers were tested for antibody-dependent cellular cytotoxicity (ADCC) against chicken erythrocytes (CRBC) with and without the addition of interferon (IFN). Maximum enhancing activity was found when the anti-CRBC antibodies in the ADCC reaction were at suboptimal concentrations. All three species of pure recombinant Escherichia coli-derived interferon were compared for their ability to enhance ADCC in both effector systems. Recombinant IFN-gamma was found to be effective at lower doses than recombinant IFN-alpha A or recombinant IFN-beta, although maximum activity for all three species was similar in the PMN system. IFN-gamma also enhanced K-cell ADCC but to a lesser extent than in the PMN system. There appeared to be individual variation in response of the K-cell ADCC system to IFN-alpha A and IFN-beta at the doses tested.