B19 parvovirus is pathogenic in humans. The virus propagates in the bone marrow, where it is cytotoxic to erythroid progenitor cells.
Antibodies appear in blood after
infection and neutralize virus in vitro;
infection appears to confer lasting immunity. The predominant immune response on immunoblot is to the minor
capsid protein (VP1), which differs from the major
capsid protein (VP2) by an additional 227
amino acids. We previously demonstrated that
antisera directed to a fusion
protein containing this unique region or to more limited fusion
peptides of 50-100
amino acids each neutralized virus. In the current work, we tested synthetic
peptides of about 20
amino acids derived from the VP1 unique region for their ability to elicit a
neutralizing antibody response in rabbits. Individual
peptides were covalently linked to a
lysine core to produce a multivalent
antigen. Animals produced
antibodies to all 13 synthetic
peptides, as determined by ELISA. At 12 weeks, animals injected with one of three
peptides--two from the far amino terminus and the third from the center of the unique region--had produced
antibodies that completely neutralized virus; by 16 weeks,
antisera elicited with another four
peptides also were effective. In summary, we identified regions containing neutralizing
epitopes within the first 80
amino acids and
amino acids 148-205 of the unique region. Our data suggest that synthetic
peptides might be useful
vaccine reagents for protection against
parvovirus infection in humans.