Papovavirus SV40 Transplantation Immunity Conferred by an Adenovirus-SV40 Hybrid2

Abstract

Further studies were made of a type 7 adenovirus-SV40 “hybrid” which carries the tumor determinant of papovavirus SV 40 in an adenovirus capsid. Vaccination of weanling hamsters with the hybrid conferred marked protection against cells transformed by papovavirus SV 40. The protection was similar to that afforded by SV40 itself. The number of cells required to induce tumors in 50 percent of the challenged animals rose from less than 100 in the controls to greater than 40,000 cells in animals previously vaccinated with either the adenovirus-SV 40 hybrid or with SV 40. Nonhybridized adenovirus type 7 failed to protect the hamsters. A few tumors occurred in the vaccinated animals, but the appearance of breakthrough tumors in hamsters inoculated with the hybrid virus closely paralleled that observed in hamsters inoculated with SV 40. The results indicate that incorporated in the adenovirus-SV 40 hybrid are the SV 40 determinants responsible for inducing the intranuclear tumor antigen but also for conferring transplantation resistance.