Demonstration of antigenic differences between strains of poliovirus type 1 by agar diffusion precipitation reaction.

Antigenic differences between type 1 poliovirus strains circulating in nature were investigated by agar diffusion precipitation reaction. Three strain-specific sera were absorbed with antigens prepared from 8 strains (Sabin's vaccine strain LSc2ab and 7 strains isolated from poliomyelitis patients or healthy persons). The results suggested the presence of at least 5 antigenic determinants in the poliovirus type 1 strains studied. Three determinants in different combinations were found in 7 strains and 2 determinants were found in 1 strain. It is assumed that antigenic differences among poliovirus strains may be due to different combinations of several antigenic determinants.