Schistosoma japonicum: isolation and identification of peptides mimicking ferritin epitopes from phage display library.

In an attempt to isolate and identify the antigenic epitopes on ferritin of Schistosoma japonicum (SjFer) and to test their protective potentiality against Schistosoma japonicum (S.j), polyclonal antisera against SjFer was prepared to screen a 12-mer random peptide library. Three rounds of biopanning were performed and resulted in an enrichment. Six peptides selected randomly from the third elute were all found to be positive by evaluating the binding to anti-SjFer sera by ELISA and Western blotting. Three amino acid sequences were deduced from the six phage clones by sequencing. When they were used to vaccinate mice, the three peptides could induce significant reduction in adult worms (26.7%, 20.4%, and 25.9%) as well as in liver eggs per gram (LEPG) (40.0%, 38.2%, and 40.8%). This result showed that three mimotopes on SjFer were obtained and they could induce significant protective efficacy against S.j.