Abstract: 　Objective To obtain the short peptides mimicking antigenic epitopes of Trichinella spiralis ( T.s. ), and explore their cross protective immunity against Schistosoma japonicum ( S.j. ) in mice. Methods IgG antibodies were purified from sera of mice infected with T.s. . The purified IgG was used to immunoscreen a phage random peptide library of 7 amino-acid residues displayed as a fusion to protein of filamentous phage. Positive clones were obtained by affinity selection, the reactivity of each clone binding to specific IgG was detected by ELISA. Kunming mice were immunized subcutaneously three times with mixed phage clones. The mice were sacrificed 45 days after challenge. The worms and the liver eggs were counted. Results After three rounds of panning, the relevant phages had been enriched approximately 150 times in production as compared to those from the first round. Of 24 phage clones randomly selected from the third round biopanning, 21 clones were shown to actually bind to the specific IgG. As compared with the control group, the worm and the liver egg reduction rates in vaccination group were 42.8% and 66.3% ( P <0.001), respectively. Conclusion The above results demonstrate that antigenic epitopes of T.s. can be prepared by immunoscreening phage random peptide library and a significant protective immunity against S.j. can be induced by these epitopes in mice.

Key words: Schistosoma japonicum, Trichinella spiralis, mimic peptide, phage display library