The use of a monoclonal antibody and of DNA recombinant technology for the localization of a poliovirus neutralization epitope in viral capsid polypeptide VP1.

Poliovirus cDNA sequences encoding type 1 capsid polypeptide VP1 were fused in phase into the beta-lactamase sequence of pBR322. The resulting recombinant plasmid pSW119 expressed in E. coli a VP1-beta-lactamase fusion protein which reacted with antibodies raised against poliovirus capsid polypeptide VP1 and with a monoclonal poliovirus type 1 neutralizing antibody C3. Deletions of various length were introduced into the VP1 sequence. The truncated proteins expressed by the deleted plasmids did not react further with C3 when the region of VP1 amino acids 91-104 was deleted. A synthetic peptide corresponding to this region of VP1 (amino acids 93-104) was chemically synthesized. It was found to inhibit the seroneutralization of poliovirus by C3 antibodies and, once coupled to keyhole limpet hemocyanin, it was specifically immunoprecipitated with C3. Therefore, the C3 epitope recognized by the poliovirus neutralizing monoclonal antibody is located within the region of amino acids 93-104 of capsid polypeptide VP1.