[Designing of ELISA kit for diagnosis of anti-toxoplasma specific IgG, using exerted/secreted antigens and its diagnosis potency]

ABSTRACT

Many studies report that Toxoplasma gondii excreted / secreted antigens [E/SA] appear to be a suitable marker for toxoplasmosis serodiagnosis. Most of these studies have used E/SA, obtained from supernatant of Toxoplasma cell culture, or by incubating tachyzoites in cell free media [RPMI-1640]. The present study for the detection of Toxoplasma IgG in human serum was evaluated, using the components of peritoneal fluid of infected mice [as another source of E/SA]. Peritoneal fluids of mice infected by interaperitoneal [IP] inoculation of Toxoplasma tachyzoites were collected after 3 days and centrifuged at 750 x g for 15 minutes. Then the supernatant was precipitated with ammonium sulphate solution [40% saturated] and used as components encompassing E/SA. Forty [40] none- infected [without anti- toxoplasma antibodies] and thirty- two [32] positive [with IgG to toxoplasma] human serum samples were selected [all sera were first tested by standard method for detection of IgG antibodies anti-T. gondii] then, the sera were tested by ELISA using E/SA. The cut-off point with 95% confidences was found to be 0.78. Moreover, sensitivity and specificity of the method were determined to be 84% and 92%, respectively. The present results indicate that peritoneal exudates from mice infected with T.gondii, may be used as a source of anti-genic material for the detection of Toxoplasma-specific IgG. Furthermore, it may be valuable for the development of new tools in the serodiagnosis of toxoplasmosis