Abstract: AIM: To observe the dynamic changes of circulating antigen in Schistosoma japonicum infection and its mechenism. METHOD: After fusion of B lymphocytes from mice infected with S.japonicum and mouse myeloma cell(SP2/0 strain), McAbs against different schistosomal antigenic epitopes were combined as probes to detect sera from schistosomiasis cases, splenic blood and peripheral blood of advanced schistosomiasis cases, portal vein blood and peripheral blood of rabbits and mice infected with S.japonicum. RESULTS: Nine monoclonal antibodies against schistosome antigen were detected by IFA. When these McAbs against different antigenic epitopes were used, in combination the sensitivity of antigen detection could be raised by 4- 8 times. established on the basis of compounded McAbs. When sandwich ELISA and dot-ELISA were used for detection of chronic schistosomiasis, the sensitivity was 74% and 84.2%, the specificity was 96.1% and 95.7%, respectively. The circulating antigen level were significantly higher in portal vein blood and splenic blood than in peripheral blood. CONCLUSION: McAbs against different schistosomal antigens used in combination in sandwich ELIAS could enhance the sensitivity of antigen detection. Not only circulating antigen but also immune complex of schistosomes were detected by dot-ELISA, so it might interfere with judgement of curative effect.

Key words: Schistosoma japonicum, monoclonal antibody, circulating antigen