Effect of TGF-β₁ exposure on cultured CB cells.

Panel A shows the proportion of total cells in G₀/G₁ after 5 days of culture of CD34⁺ CB cells in the presence of FL, SF, IL-3, IL-6, and G-CSF (5GF) and then for an additional 24 hours in 5 new culture conditions: in medium plus 5 GF (as previously) either without (■) or with TGF-β₁ (▪), or in LTC medium on preestablished bone marrow stroma layers (BM St) either without (■) or with TGF-β₁ (▪), or with 5GF (▨). Cell cycle analyses were performed by FACS after staining of fixed cells with PI. Panel B compares the number of total cells, CFCs, and LTC-ICs in the same 3 experiments.