Failure of Mouse Peritoneal Macrophage Activation by the Purified Excreted/Secreted Antigens of Toxoplasma gondii

This study was carried out to evaluate the effect of excreted/secreted antigens on macrophages infected by Toxoplasma gondii. Six proteins 28, 30, 45, 58, 63 and 145 kDa were separated by different chromatographic techniques. Mouse peritoneal macrophages were treated in vitro and in vivo with these purified fractions. Penetration and proliferation assays of T. gondii in the macrophages were performed in vitro. The different antigens used did not change the rate of penetration and proliferation of the parasites. Therefore, the secreted products, which are capable of provoking an immune response, could not directly activate the macrophages. Furthermore, the secreted products were not cytotoxic and neither did they possess a visible phospholipasic activity which would have increased penetration.