Comparison of neuropathogenicity of poliovirus type 3 in transgenic mice bearing the poliovirus receptor gene and cynomolgus monkeys

To clarify the similarities of poliovirus infection in cynomolgus monkeys a nd transgenic mice bearing the poliovirus receptor. TgPVR21, we compared th e pathological changes of these animals following intraspinal inoculation o f two strains of poliovirus type 3 using immunohistochemical detection of t he capsid antigen. All of the monkeys inoculated with 10(6) TCID50 viruses showed flaccid paralysis 2 or 3 days post-inoculation (p.i.). TgPVR21 mice showed paralysis starting from 2 to 3 days p.i. Histologically, neurons hav ing pyknotic nuclei and eosinophilic cytoplasm and neuronophagia were chara cteristically observed in both animals, but central chromatolysis was not o bserved in infected TgPVR21. The median lesion scores in the monkeys and Tg PVR21 were well correlated, though the distribution of poliovirus-infected lesions in the central nervous system was different. In both animals the mo tor neurons and the brainstem nuclei responsible for flaccid paralysis were infected by the virus, while the cerebral cortex and thalamus were infecte d in the monkeys but not in TgPVR21. These results confirmed the reliabilit y of neurovirulence tests using TgPVR21 as a substitute for monkeys, in res pect to the spinal and brainstem lesions of poliovirus type 3. (C) 2001 Els evier Science Ltd. All rights reserved.