Effect of interferon on cell proliferation and generation of cytotoxic potential in mixed autologous and allogeneic lymphocyte cultures.

Autologous and allogeneic mixed lymphocyte cultures (AMC and MLC) were assayed for blastogenesis, generation of cytotoxic potential, and the effect of interferon (IFN-alpha) on these features. The cells of the mixed cultures lysed K562, Daudi, and autologous and allogeneic phytohaemagglutinin blasts. Stimulator-specific cytotoxicity was observed only in MLC. B blasts induced with Staphylococcus aureus were only affected in a stimulator-specific manner. Short-term IFN treatment of the MLC-derived effectors before the lytic assay enhanced the nonspecific component of cytotoxicity. Cell proliferation was considerably lower in AMC than in MLC. This was decreased when IFN-alpha was added at the initiation of the cultures. The presence of IFN influenced the generation of lytic potential. Comparison of the lysis of the different targets exerted by MLC-activated cells suggested that the specific component was more substantially elevated than the nonspecific one. It is likely that the IFN induced such modifications in the culture conditions that favoured the proliferation of the specific clone. Re-exposure of lymphocytes cultured in the presence of IFN to another dose of IFN before the assay had no influence on their lytic potential.