Principal and subsidiary antigenic sites of VP1 involved in the neutralization of poliovirus type 3.

The characterization of over 300 mutants, derived from two strains of poliovirus type 3 and selected for resistance to neutralization by monoclonal antibodies, has led to the further definition of the major antigenic site involved in neutralization. The site encompasses amino acids 89 to 100 of VP1. A subsidiary antigenic site near the C-terminus of VP1 has been identified for the Sabin vaccine strain of poliovirus type 3. Of 59 monoclonal antibodies to poliovirus type 3 examined, 27 had virus-neutralizing activity and 25 of these were identified as directed against the major site on VP1 (designated site 1), indicating the immunodominant role of this site. One of the six monoclonal antibodies that recognized the subsidiary antigenic site on VP1 (designated site 2) possessed virus-neutralizing activity. The identification of the principal antigenic site of the virus provides a rational basis for attempts at the development of synthetic oligopeptide vaccines against poliovirus type 3.