Abstract
SV 40-transformed hamster cells were relatively resistant to the lytic effect of activated macrophages from animals with chronic intracellular infections. Conversely, SV 40-transformed mouse and rat cells and adenovirus 2-transformed hamster cells were highly susceptible to destruction by tumoricidal activated macrophages. The pattern of resistance or susceptibility of SV 40-transformed rodent cells was the same whether activated macrophage effectors were obtained from mice, random-bred hamsters, or the inbred LSH hamsters from which some of the SV 40-transformed hamster lines were derived. The results suggest that resistance of transformed cells to macrophage-mediated cytolysis may explain in part the species-specific oncogenicity of this DNA virus.