To explore the mimotope vaccine approach against infectious bursal disease virus 
(IBDV), five IBDV-specific monoclonal antibodies (mAbs) were prepared and their 
binding peptides were screened against a phage-displayed 12-mer peptide library. 
After three rounds of biopanning, 12 phages were selected for each mAbs and 
their specificity to IBDV was verified by sandwich and competitive inhibition 
ELISAs. Seven phages per mAb were sequenced and their amino acid sequences were 
deduced. The five representative sequences of mimotopes corresponding mAbs were 
determined. An artificial gene, designated 5epis (5 epitopes) and consisting of 
the five mimotopes arranged in tandem (F1-F7-B34-2B1-2G8) with four GGGS 
spacers, was chemically synthesized and cloned into a prokaryotic expression 
plasmid pET28b. The protein, designated r5EPIS, was efficiently expressed in 
Escherichia coli and showed a size of 10kDa in SDS-PAGE. The r5EPIS protein 
reacted with anti-IBDV mAbs and polyclonal antibodies in Western blot 
immunoassays. Immunization of SPF chickens with r5EPIS protein (with Freund 
adjuvant, 50mug per injection on day 0 and 14) evoked high levels of antibody 
(12,800 by ELISA/1600 by virus neutralizing assay at day 21) and protected 100% 
of the chickens against a challenge of 200 ELD(50) of IBDV GX8/99 strain, which 
sharply contrasted with the, respectively, 13.3% and 6.6% survival rate in the 
adjuvant group and the untreated group. The multi-mimotope protein r5EPIS 
promises to be a novel subunit vaccine candidate for IBDV.