Immunoreactivity of human and rabbit antisera to hepatitis A virus.

Rabbit antibodies produced by immunization with complete hepatitis A virions (HAV) recognized all the viral structural proteins and neutralized HAV infectivity in cell culture. Rabbit antibodies to chromatographically purified individual viral proteins and to synthetic peptides representing epitopes on the structural viral protein VP1 neither recognized whole virus nor neutralized infectivity, indicating that native epitopes on the virus surface are necessary for virus recognition and neutralization. Human anti-HAV-positive sera of the acute and convalescent phase of disease recognized and neutralized viral particles. Analysis of the immunoreactivity of these human sera in immunoblot showed that the IgM antibody preferentially recognizes the structural viral proteins VP0 and VP3 of HAV, whereas IgA and IgG antibodies reacted more strongly with VP1.