Identification of B cell epitopes of infectious bursal disease virus VP3 expressed in E. coli.

To identificate B cell epitopes on the VP3 protein of infectious bursal disease virus(IBDV),the VP3 gene of IBDV was subcloned into the pET28a vector and expressed in E.coli BL21(DE3) by inducing with IPTG.The expressed VP3 protein could be recognized specifically by anti-IBDV antisera in western blot assay.Overlapping peptides that span the full sequence of VP3 were synthesized and conjugated to carrier protein BSA to prepare conjugated antigens.Their reactivity with anti-IBDV monoclonal antibodies(MAb) or polyclonal antibody was detected by peptide-ELISA and Dot-ELISA.Two linear epitopes,728PRDWDRLPYLNL739 and 982PKPKPKPNAPTQ993,were identified by VP3 specific neutralizing MAbs,which could also react with IBDV antiserum.Dot-ELISA confirmed that there were 4 more linear epitopes recognized by polyclonal antibody against the VP3 protein.These epitopes could be developed as potential IBD epitope vaccine.