FIG. 4.

Reduced proliferation recruitment of single primitive hematopoietic progenitors in vitro. Single LSK cells were seeded directly into serum-free medium containing 25 ng of SCF, FL, TPO, and G-CSF/ml and 10 ng of GM-CSF and IL-3/ml to assay for in vitro expansion. After 10 days of culture, the cloning frequency (open bars) and clone size (shaded bars, representing the percentage of high proliferative clones covering >50% of the well) were evaluated. The results represent the mean ± the SD values of two experiments.