Possible Relationship Between Two Primate Papovaviruses, Human Wart and Simian SV402

Abstract

Vaccination of weanling hamsters with simian papovavirus SV40 conferred marked protection against challenge by cells transformed in vitro or in vivo by the homologous virus. A greater than 1,000-fold increase was observed in the number of cells required to produce subcutaneous or pouch tumors in 50 percent of the inoculated animals after 3 prior injections of SV40 virus. Prior inoculation with human wart papovavirus also protected hamsters against subsequent subcutaneous challenge with SV40-transformed cells. The protection resulted in a 100-fold increase in the number of cells necessary to induce tumors. Vaccinated animals challenged by inoculation into the cheek pouch, however, were not protected. When breakthrough occurred, the tumors developing in challenged animals previously vaccinated with either human wart virus or SV40 virus required a longer incubation period and developed more slowly than the tumors in the control animals.