Abstract: 　Objective To explore the immunological characteristics of the membrane antigen from hepato-portal juveniles of Schistosoma japonicum and its protective immunity against S. japonicum (Sj) in mice. Methods Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE) and enzyme-linked immune electro-transfer blot(EITB) methods were used to recognize the membrane antigens from hepato-portal schistosomula (SjHmAg) by infected rabbit sera (IRS) and normal rabbit sera (MRS). Kunming mice were immunized subcutaneously three times(0,2,4weeks) with SjHmAg. Each mouse was challenged with 40±1 cercariae. Six weeks later the mice were killed, worms and liver eggs were counted. Results 7 major protein bands appeared on SDS-PAGE. IRS mainly reacted specifically with SjHmAg of 23, 33 and 63 kDa. Compared with the control groups, the reduction rate of worms and eggs per gram liver in the experimental group were 16.2% and 54.4 % , respectively. Conclusion Different protein components from SjHmAg are obtained using SDS-PAGE, and the antigen can induce a protective immunity against Sj in mice.

Key words: Schistosoma japonicum, hepato-portal schistosomula, membrane antigen, immunity, protection