THE INHIBITORY EFFECT OF OVINE RECOMBINANT INTERFERON-GAMMA ON INTRACELLULAR REPLICATION OF TOXOPLASMA-GONDII

A model for the in vitro infection of ovine cells with Toxoplasma gond ii tachyzoites has been developed and used to investigate the effect o f treatment with ovine recombinant interferon-gamma (ov.rIFNgamma) on parasite replication. Treatment of both alveolar macrophages and fibro blast cells either 24 h pre-infection or 2 h post-infection with ov.rI FNgamma inhibited replication of T. gondii and was quantified by suppr ession of H-3 uracil uptake by the parasite. Replication of T. gondii in the fibroblast cells was significantly inhibited by treatment with 200-300 U/ml ov.rIFNgamma, whereas concentrations as low as 1 U/ml sup pressed parasite replication in the alveolar macrophages.