Poliovirus type 1/type 3 antigenic hybrid virus constructed in vitro elicits type 1 and type 3 neutralizing antibodies in rabbits and monkeys.

Poliovirus exists as three stable serotypes (PV-1, PV-2, and PV-3). These viruses display three antigenic sites each, designated N-AgI, N-AgII, and N-AgIII. When mice are immunized with poliovirus, N-AgI is the major neutralization antigenic site for PV-3, whereas N-AgII and N-AgIII are immunodominant over N-AgI for PV-1. To study the relationship between structure and antigenicity, a hybrid virus was constructed in which N-AgI of PV-1 was replaced by N-AgI of PV-3. PV-3- and PV-1-specific antisera, including those elicited by PV-3 in primates, neutralized the hybrid virus. Injection of the hybrid virus into rabbits or into primates resulted in the production of antisera that neutralized both PV-1 and PV-3. The data show that sequence replacement at N-AgI of poliovirus is compatible with viral proliferation, an observation useful for the development of multivalent picornavirus vaccines.