Structural proteins of poliovirus type 2 isolates.

Seventeen strains of type 2 poliovirus isolated from vaccines and vaccine-contacts in Japan were analyzed for viral structural proteins by sodium dodecyl sulfate polyacrylamide gel electrophoresis. An alteration in electrophoretic mobility of VP1 was observed in most of the strains from paralytic patients and healthy vaccinees. The alteration in VP1 was observed at a high frequency among many strains, but no significant relation between the mobility change of VP1 and antigenic marker or rct/40 marker was observed. No alteration in mobility of other structural proteins was observed among the strains examined except for one with altered VP3. The results suggested that VP1 of Sabin type 2 strain was easily changeable during replication in human intestines.