Properties of an SV40‐transformed hamster cell line resistant to actinomycin D

The biological properties of a hamster cell line Cl 2 TSV‐5/R derived from an SV40 tumour and made resistant to Actinomycin D (2 μg/ml) were investigated, in particular: tumorigenicity in vitro growth on plastic or in soft agar, agar, persistence of SV40 specific neoantigens (T and TSTA), and caryotype. When compared to the parental cell line (Cl 2 TSV‐5), the tumorigenicity and the ability to grow in soft agar of the Cl 2 TSV‐5/R cells were strongly reduced (approximately 1,000 fold). Their growth on plastic was also clearly slowed. Although the SV40 T antigen was still present in all the resistant cells they no longer had immunosensitivity to the SV40 specific graft rejection test. The caryotype of Cl 2 TSV‐5/R cells was comparable to that of the Cl 2 TSV‐5 cells.