Serological Diagnosis Of Toxoplasmosis Using Combinated Recombinant Surface Antigen SAG1, Hypoxanthine-xanthine-guanine-phosphoribosy-ltransferase And Adenosine Kinase Of Toxoplasma Gondii

Objective: Three recombinant antigens surface antigen SAG1, hypoxanthine-xanthine-guanine-phosphoribosyltransferase(HXGPRT), and adenosine kinase(AK) of Toxoplasma gondii were evaluated for their potentiality in diagnosis of suspected patients with toxoplasmosis, who has been screened by commercial ELISA kit. Methods: The PCR product of Toxo-SAG1 was cloned into pET28a vector and E. coli BL21 was transformed followed by IPTG induction for expression . The expression vectors of Toxo-HXGPRT/pET28a/BL21 and Toxo-AK/pET28a/ BL21, which had been stored in our laboratory, were simultaneously induced by IPTG and identified by Western blotting. The rSAG1, rHXGPRT, and rAK were mixed at the ratio of 1:1:1 and the optimal working concentrations were optimized. Combination of the three recombinant antigens were used in ELISA for the detection of sera of rabbits with Toxoplasma infection and eleven suspected pregnant women, who had been screened by commercial.diagnostic kit. Results: Working concentrations of rSAG1, rHXGPRT, and rAK antigens in rabbit sera were 500ng/ml, 200ng/ml and 100ng/ml, respectively , while in human sera, were 500ng/ml, 200ng/ml and 200ng/ml, respectively . The working dilution of sera was 1:2000 in rabbits and 1:20 in pregnancies .The sensitivity, specificity and accuracy in rabbit sera were 1:10000, 75.31% and 10.05%, respectively, while in human sera, were 1:200 ,72.36% and 11.2%, respectively. Conclusion:the present study demonstrates that combination of the recombinant major antigens in ELISA have high sensitivity, specificity, and reliability and useful in the serodiagnosis of pregnancies with suspected Toxoplasma infection.