Preparation, Purification and Identification of Excreted/Secreted Antigens of Toxoplasma Gondii Tachyzoites

The Excreted/Secreted antigens (E/SA) of toxoplasma gondii tachyzoites are thought to play an important role in the pathogenesis of parasite and the hosts, immunity against infection with this Parasite. These antigens are also useful for diagnosis and differentiation of acute from chronic phase of toxoplasmosis. Therefore the aim of the present study was to detect the best technique for preparation, purification and identification of these antigens. Tachyzoites (2×108) were incubated at 37°C for 1hour under mild agitation in test–tubes containing 2ml of RPMI-1640 culture medium without FCS. After centrifugation for 15min at 1000g the E/SA containing supernatant were dialyzed and concentrated. E/SA were separated by gel filtration and ion exchange chromatography. Fractions of both chromatography columns were analyzed by Native–PAGE electropho_ resis. E/SA were eluted in three and two Peaks by gel filtration and ion-exchange chromatography respectively. The second peak obtained from ion-exchange chromatograp_ hy produced one band in native – PAGE. The result of this experiment showed that ion-exchange chromatography under this conditions is a good tool for purification of E/SA.