Immunization of Mice with Inactivated Type 2 Poliomyelitis Virus Against Types 2 and 3 Viruses

Abstract

The newborn-mouse adapted MEF1 strain of poliomyelitis virus, a Lansing, or Type 2 virus, developed an increasing immunizing power in mice vaccinated with formalin-inactivated virus. The adapted strain had a far greater immunogenic potency than the standard, unadapted strain when the vaccinated mice were challenged intracerebrally with the homotypic virus. In addition, a significant and reproducible cross-protection was detected when the vaccinated mice were challenged intraspinally with heterotypic Type 3 (Leon) strain of poliomyelitis virus.