Monospecific antisera against capsid polypeptides of poliovirus type 1 distinguish antigenic structures of poliovirus proteins.

Pure poliovirus polypeptides, namely VP1, VP2, VP3 and VP4, have been isolated by isoelectric focusing after dissociation of poliovirus by urea. When injected into rabbits, all four polypeptides produced monospecific antisera which were used for the characterization of poliovirus particles and poliovirus-infected cells. The specificity of these antisera was determined by immunoprecipitation of polypeptides obtained by dissociation of poliovirus with SDS, followed by characterization by polyacrylamide gel electrophoresis. The antisera revealed differences in the antigenic sites of native poliovirus particles, heated poliovirus particles and naturally occurring empty capsids. Only VP3 antiserum reacted with native poliovirus and showed some neutralization, whereas all antisera precipitated heated virus and empty capsids. These antisera reacted also with the appropriate precursors of the capsid polypeptides demonstrating their usefulness for an analysis of the cleavage pathway by monospecific antibodies and revealed a second protomer (90 kilodalton) polypeptide for the capsid proteins of poliovirus particles.