Isolation of escape mutants of a hybrid poliovirus with the aid of insert-specific polyclonal antibodies.

We constructed a hybrid type 1/type 3 poliovirus comprising the BC-loop of capsid protein VP1 of PV3/Finland/60212/84 and the rest derived from PV1/Mahoney, and cultured the virus in the presence of diluted rabbit antiserum to PV3/Finland/60212/84. Several strains isolated under this selection showed point mutations in the inserted type 3 poliovirus sequence but only in one case in the flanking PV1/Mahoney-derived RNA. These results indicate that, with the use of recombinant cDNA technology, it may be possible to study molecular interactions of defined regions of virus capsid proteins with neutralizing polyclonal antibodies.