SV40-TRANSFORMED HUMAN DIPLOID CELLS THAT REMAIN TRANSFORMED THROUGHOUT THEIR LIMITED LIFESPAN

Of 91 subcultured foci of SV40-transformed WI-38 human diploid fibroblasts, none yielded cells that grew indefinitely, but all cells in each subculture continued to produce T [tumor] antigen and to look morphologically transformed throughout their lifespan. These results are consistent with the commitment theory of fibroblast senescence, but predict that a special transformation event is necessary to account for the rare survivors.