INHIBITION OF EIMERIA-TENELLA DEVELOPMENT IN-VITRO MEDIATED BY CHICKEN MACROPHAGES AND FIBROBLASTS TREATED WITH CHICKEN-CELL SUPERNATANTS WITH IFN-GAMMA ACTIVITY

Pretreatment of chicken macrophages or fibroblasts with supernatants f rom concanavalin A-stimulated spleen cells or from the virus-transform ed cell line reticuloendotheliovirus as source of interferon gamma (IF N-gamma) slows down subsequent sporozoite replication in the cells. To identify the presence of IFN-gamma, we combined four typical activiti es of IFN-gamma: inhibition of cytopathic effect of vesicular stomatit is virus on IFN-gamma-treated fibroblasts, cytostatic activity of IFN- gamma-activated macrophages, induction of major histocompatibility com plex II antigen expression on IFN-gamma-activated fibroblasts and macr ophages, and induction of nitrite production in macrophages. We have s hown that chicken fibroblasts and macrophages possess a microbiostatic capacity once they are able to prevent the otherwise unchecked intrac ellular replication of Eimeria tenella following activation with cultu re supernatants identified as containing a strong IFN-gamma activity.