Neutralizing linear epitopes of B19 parvovirus cluster in the VP1 unique and VP1-VP2 junction regions.

Presentation of linear epitopes of the B19 parvovirus capsid proteins as peptides might be a useful vaccine strategy. We produced overlapping fusion proteins to span the viral capsid sequence, inoculated rabbits, and determined whether the resulting antisera contained antibodies that neutralized the ability of the virus to infect human erythroid progenitor cells. Antibodies that bound to virus in an enzyme-linked immunosorbent assay were present in antisera raised against 10 of 11 peptides; strongest activity was found for antisera against the carboxyl-terminal half of the major capsid protein. However, strong neutralizing activity was elicited in animals immunized with peptides from the amino-terminal portion of the unique region of the minor capsid protein and peptides containing the sequence of the junction region between the minor and major capsid proteins. The development of neutralizing activity in animals was elicited most rapidly with the fusion peptide from the first quarter of the unique region. A 20-amino-acid region of the unique region of the minor capsid protein was shown to contain a neutralizing epitope. Multiple antigenic peptides, based on the sequence of the unique region and produced by covalent linkage through a polylysine backbone, elicited strong neutralizing antibody responses. Synthetic peptides and fusion proteins containing small regions of the unique portion of the minor capsid protein might be useful as immunogens in a human vaccine against B19 parvovirus.