Kinetics of activation of CD34⁺CD38⁻ BM stem cells.

Kinetics of initiation of clone (doublet) formation by single CD34⁺CD38⁻ BM cells cultured individually in 96-well plates in serum-free medium supplemented with either FL + SF + IL-3 (■, ○), FL + SF + IL-3 + HIL-6 (░, ♦), or FL + SF + IL-3 + HIL-6 + TPO (▪, ●). Panel A shows the number of wells containing a first doublet as a function of time. Panel B shows the same data as a cumulative plot. Values shown are the mean ± SEM of data pooled from 4 independent experiments.