Conformational antigenic determinants generated by interactions between a bacterially expressed recombinant peptide of the hepatitis C virus structural protein

A 23 kDa peptide locating to amino acid residues 394 to 604 of the major He patitis E Virus (HEV) structural protein was expressed in E. coli. This pep tide was found to interact naturally with one another to form homodimers an d it was recognized strongly and commonly in its dimeric form by HEV reacti ve human sera. The antigenic activity associated with the dimeric form was abrogated when the dimer was dissociated into monomer and the activity was reconstituted after the monomer was re-associated into dimer again. The dim eric form of the peptide elicited a vigorous antibody response in experimen tal animals and The resulting antisera were found to cross-react against HE V, effecting an efficient immune capture of the virus. These results attrib uted the antigenic activity associated with the dimeric form of the peptide to conformational antigenic determinants generated as a result of interact ion between the peptide molecules. It is suggested that some of these antig enic determinants may be expressed by the HEV capsid and raised the possibi lity of this bacterially expressed peptide as an HEV vaccine candidate. (C) 2001 Wiley-Liss, Inc.