Characterization of normal human embryo cells grown to over 100 population doublings

Summary Normal human embryonic cells were subcultured for over 100 population doublings without modification of the basic medium. The cells were evaluated for growth rate, confluent density, chromosome stability, growth in soft agar, ability to hydrolyze casein and tumorigenicity. The cells possessed the characteristics of normal cells. The batch of serum used to supplement the medium was found to be of primary importance in the long-term growth of this cell culture. Research sponsored by the National Cancer Institute under Contract No. NO1-CO-25423 with Litton Bionetics, Inc.