Objective: To develop multiple B cell epitope antigens of Schistosoma japonicum and evaluate their antigenicity.
Methods: Bioinformatics software BioSun was used to predict B cell epitopes from Sj22.6, Sj14-3-3 and Sj26. The predicted epitopes P2, P6 and P7 were ligated to construct P2-P6-P7 and P6-P2-P7 multiepitope in random order, a 6 amino acid linker inserted between epitopes. Recombinant plasmids containing the two multiepitopes identified by enzyme digestion and sequencing were transformed into E. coli BL21. The expressed recombinant fusion proteins of E. coli BL21 induced with IPTG were purified with Ni2+ chelating HiTrap HP column. Their antigenicity was evaluated with Western-blotting.
Result: The two multiple B cell epitopes P2-P6-P7 and P6-P2-P7 were successfully cloned into pET-32c(+) plasmid and fusion proteins were expressed. SDS-PAGE showed a single band and both of the recombinant fusion proteins were with Mr 20 400. The two proteins reacted with the sera of schistosomiasis patients but not with that of healthy people.
Conclusion: Two multiple B cell epitope antigens were developed with potential diagnosis value.