Profiles of proliferative responses of UT-7/GM cells to various cytokines. Proliferative responses of UT-7/GM cells to cytokines were analyzed by the MTT assay (see Materials and Methods). Cells were plated at a density of 10⁴/well in IMDM supplemented with 5% FCS and cultured with TPO (100 ng/mL), IL-3 (10 ng/mL), GM-CSF (10 ng/mL), EPO (10 U/mL), SCF (100 ng/mL), or IL-6 (100 ng/mL). MTT reduction was measured after 3 days of culture. The values represent the mean ± SD from triplicate cultures.