Figure 2.

Production of hematopoietic cells in long-term cultures of human hematopoietic stem cells. (a) Eight independent experiments were performed using eight different umbilical cord blood samples and OP9 cells as feeder cells. (b) Seven independent experiments were performed using seven different umbilical cord blood samples and C3H10T1/2 cells as feeder cells. ((a), (b)) The number of detached cells in the overlying medium was counted at each medium change (approximately half weekly). The data are shown as the mean number of detached cells produced from a single CD34(+) cell, that is, the total number of detached cells divided by the number of CD34(+) cells used to initiate the culture. Exp: experiment. A to I after Exp-OP9 and Exp-10T1/2 indicate 9 different umbilical cord blood samples derived from 9 different neonates. #: Cultures Exp-OP9-A and Exp-10T1/2-F were terminated because of fungal infection.