Protective immunity against Schistosoma japonicum induced by epitopes mimicking cercariae antigens of Schistosoma ja-ponicum.

Objective To immunoscreen mimic epitopes of Schistosoma japonicum(Sj) cercariae antigens and explore their immunoprotection against Sj. Methods Phage random peptide library of 12 amino acids was immunoscreened with purified IgG from mouse sera immunized with Sj cercariae antigens. Positive clones collected after three rounds of biopanning were detected by Dot -ELISA. Mice were immunized with mixed positive phage clones for three times, and all mice were perfused 45 days after challenge with Sj cercariae.The worms and liver eggs were counted. Results The specific phages-binding to IgC were enriched after three rounds of biopanning. Eleven clones detected by Dot - ELISA bound to the specific IgG of sera immunized with Sj cercariae antigens. Sera immunized with mixed positive phage clones reacted with Sj cercariae antigens. Immunoprotection against Sj was induced by immunization of mixed phage positive clones. Conclusion The specific antigenic epitopes mimicking Sj cercariae antigens were obtained by im-munoscieening phage random peptide library and immunoprotection can be induced by these epitopes.