[The effect of gamma-interferon and phorbol myristate acetate on the Fc gamma-receptor ligand-binding capacity and on the target-conjugating and antibody-dependent cytotoxic activity of blood lymphocytes].

We investigated the ability of gamma-interferon (IFN-gamma) and phorbol 12-myristate 13-acetate (PMA) to influence the ligand-binding of Fc-receptors for immunoglobulin G (Fc gamma R) (conjugation of IgG to fluorescein izothiocyanate--FITC) of bovine blood lymphocytes and the antibody-dependent cell-mediated cytotoxic activity (ADCC). The results demonstrate that the IFN-gamma or PMA induced augmentation of ligand-binding capacity of Fc gamma R of bovine lymphocytes, and correlated well with the enhanced capacity to lyse L cells coated with anti-L cell antibody. The number of conjugates effector--target, formed by bovine lymphocytes in the reaction of ADCC, correlates well with ligand-binding capacity of Fc gamma R. It can be suggested that IFN-gamma or PMA may control the ADCC caused by Fc gamma R regulating its expression.