Inactivated poliovirus vaccine protects transgenic poliovirus receptor mice against type 3 poliovirus challenge

Transgenic (Tg) mice expressing the human poliovirus receptor (PVR) were vaccinated with inactivated poliovirus vaccine (IPV) and evaluated for induced immunity against type 3 poliomyelitis. One injection of monovalent type 3 IPV elicited protective immunity against wild-type poliovirus, In contrast, 2 injections of trivalent IPV were required for protection. Neutralizing antibody response and protection were vaccine dose-dependent. Administration of polio-immune mouse plasma protected unimmunized mice, demonstrating that neutralizing antibody was sufficient for immunity. IPV heated to remove its D antigen component did not induce protection in Tg PVR mice, IPV derived from a wild-type poliovirus strain gave better protection against wild-type viral challenge than IPV derived from an attenuated poliovirus strain, The newly developed Tg PVR mouse-protection test may be useful in evaluating existing IPV potency tests and for attempts to improve formulations of trivalent IPV or combined vaccines for childhood immunization schedules.