Diagnosis Study On Schistosomiasis Japonicum In Domestic Animals With Recombinant Antigen PGEX-BSjGCP-BSj23 As Diagnosis Antigen

Schistosomiasis japonicum, prevailing around 12 provinces (municipality, autonomous region) in South China, has been causing seriously threat to health of human and animals. Precise diagnosis is the basement for prevention and treatment of a disease. However, there is no satisfaction for diagnosis of the disease by methods available. It is an urgent need to search for an approach with higher sensitivity and specificity as well as potential value on chemotherapeutic efficacy.In the present study, the optimal conditions for expressions of recombinant strains of pGEX-BSjGCP-BSj23 and pGEX-LHD-Sj23 were searched and determined. Inclusion body of recombinant antigen pGEX-BSjGCP-BSj23 was purified by the method of urea-denaturation-dialysis-refolding and Protein Refolding kit, both of which were compared for optimization of purification for the inclusion body. The conditions for ELISA were also optimized through trail of cross-chess. By ELISA with recombinant antigens pGEX-BSjGCP-BSj23 and pGEX-LHD-Sj23 and soluble egg antigen SjSEA as diagnosis antigen,70 sera from water buffalos free of infections and 104 sera from these with infection of Schistosomiasis japonicum were detected and the sensitivity and specificity of the three establishemnts were compared. By pGEX-BSjGCP-BSj23-ELISA, sera from infected water buffalos with different intensity were detected for evaluation of the recombinant antigen in diagnosis. By ELISA with recombinant antigens pGEX-BSjGCP-BSj23 and pGEX-LHD-Sj23 and soluble egg antigen SjSEA as diagnosis antigen, levels of three specific antibodies were tested in rabbit sera prior to infection,2 weeks,4 weeks,6 weeks post infection and every month post treatment. The variation of growth and decline of the three specific antibodies in rabbit sera were analyzed and the chemotherapeutic efficacies of the three methods were evaluated. The results showed that sensitivities of recombinant antigen pGEX-BSjGCP-BSj23 and soluble egg antigen SjSEA are equivalent in detection of Schistosomiasis japonicum in water buffalo while the specificity of the former is slightly higer than that of the latter, but diagnosis values of both are better than that of recombinant antigen pGEX-LHD-Sj23, recombinant antigen pGEX-BSjGCP-BSj23 has the potential for diagnosis of sera from water buffalo with low intensity in some extent and for evaluation of chemotherapeutic efficacy with the reason that the antibody specific to recombinant antigen pGEX-BSjGCP-BSj23 appears in short time after infection and disappears quickly post treatment, while recombinant antigen pGEX-LHD-Sj23 and soluble egg antigen SjSEA could be lack of the value for chemotherapeutic efficacy as the specific antibodies against the both antigens in rabbit sera were detected lately post infection and could persist at high level considerately for a long time after treatment.