Table 1.

Production of CD34⁺CD38⁻ Cells by Single Cells in Serum-free Medium Supplemented with Steel Factor, Flt-3, IL-3, IL-6, and G-CSF

Category		Production of CD34+CD38− cells up to day		No. of clones (n = 121)		Proportion (%)		Maximum CD34+CD38− expansion*		Average cell-cycle time (h) up to day 9‡
A		16		73		60		4.4 × 103		20.8 ± 0.2
B		59		29		24		6.6 × 107		24.8 ± 0.1
C		129		19		16		2.7 × 1012		32.0 ± 0.1

^* Obtained by repeated sorting and reculture of CD34⁺CD38⁻ cells in 1-ml cultures until no more CD34⁺CD38⁻ cells were produced.  

^‡ Obtained by dividing the culture period in hours by the log₂ of the estimated number of cells (n) at day 9.