In vitro transformation of mouse embryo cells by SV 40 DNA

The oncogenicity of SV 40 DNA was examined in mouse embryo cell cultures in vitro. T antigen induction in mouse embryo cells by SV 40 DNA was predominant at 5 days after infection and T antigen positive cells were observed by more than 10% at this stage. They decreased with increasing time until about 30 to 50 days of culture, after which numbers of cells with positive T antigen increased again to 36 to 38% with morphological changes accompanied. Morphological alterations seen at about 100 days after infection were characteristic of SV 40 transformed cells, e.g., criss-cross appearance, giant cell formation and irregurality of cell arrangements.