Abstract: 　AIM: To explore an efficient method for preparing monoclonal antibodies against circulating antigen of S.japonicum in the urine of schistosomiasis patients. METHODS: The urine of schistosomasis patients were precipitated with 5% trichloroacetic acid,and then used to immunize the BALB/c mice by intrasplenic immunization to prepare McAb. RESULTS: Two monoclonal cell lines against the CAg in the urine of schistosomiasis patients have been established.The immunoglobulin subclass of the 2 McAbs (2E6 and 2B11) were identified as IgM.The titres of 2E6 and 2B11 were 2.56×10 5 and 6.4×10 4. On immunodiffusion , McAb 2E6 showed one precipitation line with IHU CAg, however, both McAbs did not react with NHU-CAg.Using ascitic fluid of 2B11 and 2E6 as capture antibody separately, and HRP H11 as labelled antibody to detect the urine of 12 acute schistosomasis patients, 2B11 2E6 gave 6 and 3 positive, respectively, whereas 8 normal urine were all negative. CONCLUSION: It is feasible to use CAg from schistosomasis patientsurine to prepare anti CAg McAb by intrasplenic immunization in mice.

Key words: Schistosoma japonicum, intrasplenic immunization, urine circulating antigen, monoclonal antibody