Sustained Propagation of Sarcoma 180 in Tissue Culture. ∗

Summary

1. A strain of Sarcoma 180 maintained by routine trocar implant passage in CFW mice has been isolated and serially propagated in vitro from biopsy specimens in a medium containing only the growth factors demonstrably essential for the HeLa cell and the L strain of mouse fibroblasts. The generation time in these media is circa 30 hrs and this cell line is now in the 32 nd transplant, having undergone more than 100 generations during 230 days in vitro. 2. Inocula prepared from these cultures after 215 days in vitro have produced characteristic sarcomata within 3-5 days in 100% of the CFW mice implanted subcutaneously with 1.0 × 10⁵ or more cells. The ED₅₀ in CFW mice is circa 4.5-5.0 × 10³ cells, and the latent period between injection and the development of palpable tumors increases with decreasing inocula.