Antigenic structure of poliovirus in inactivated vaccines

The reactivity of D antigen-specific monoclonal antibodies with infectious virus and inactivated virus in commercial poliovaccines from two manufacturers was examined in capture enzyme immunoassays. Epitopes on inactivated poliovirus types 2 and 3 in vaccines were modified by the inactivation process to such an extent that some monoclonal antibodies which bound to the homologous infectious virus strain failed to bind to the inactivated virus in the vaccine. This was especially the case for antibodies specific for site 1, which elicits the major immune response to these serotypes in mice. Other epitopes were partially destroyed resulting in a reduction in reactivity of monoclonal antibodies with inactivated virus in vaccines compared to infectious virus. These studies indicate that inactivated virus in vaccine differs antigenically from native virus so that measuring the potency of vaccine in assays in vitro may require careful selection of an appropriate antibody. In addition it is possible that some of the antibodies produced by recipients of formalin-inactivated polioviruses may not contribute to the protective immune response.