Isolation and long-term culture of diploid mammalian cell lines.

Cells have been established in continuous culture from human and animal tissues, both normal and carcinomatous. From 197 specimens, 105 could be maintained in vitro for varying lengths of time, 27 for more than 6 months. In all cases the cells were found to be diploid. Cell lines with both epithelial and fibroblastic morphology have been isolated in medium 199 with added fetal calf serum, but all lines maintained over long periods have eventually become fibroblast-like. Following the additional use of other synthetic media, cells with epithelial morphology have retained their characteristic shape for up to 3 months.