RAPA has no effect on CFU-GMs. Normal bone marrow CD34⁺ HPCs were incubated with appropriate media: H4230 supplemented with 10% 5637-CM to obtain CFU-GMs (n = 3); H4435 to obtain CFU-Ms (n = 6); and H4535 to obtain BFU-Es (n = 3), and in the presence of increasing concentrations of RAPA (▪, 0 nM; ▦, 1 nM; ▧, 10 nM; □, 100 nM). The colonies (more than 50 cells) were scored at day 14. Results are expressed as percentage of control and are mean ± SEM of duplicates.