Antigenic Differentiation of Polioviruses by Absorbed Hyperimmune Sera

The antibody absorption method for the preparation of highly specific antisera against Type I vaccine and virulent strains has been applied in an epidemiologic study. A total of 119 Type I polioviruses isolated in Israel during a 3-year period were tested for their antigenic relationship to LSc-2ab virus. All isolates from the prevaccination period were different from the vaccine, enabling identification of strains from these groups by antigenic marker. Strains excreted by vaccinated children early after feeding (1 week) were also clearly classified, in this case as vaccine-like. In viruses excreted by vaccinated children in later periods after feeding, antigenic change, observed also by other authors, was confirmed by the antibody absorption method. The greater sensitivity of this method is emphasized.