(A) Growth curve of UG3 cells cultured in the presence or absence of IL-3 (5 ng/mL), GM-CSF (1 ng/mL), G-CSF (10 ng/mL), or M-CSF (100 ng/mL). Cells were enumerated with a hematocytometer after trypan blue dye exclusion. Error bars indicate standard deviation of cell numbers. (B) Growth of UG3 cells cultured in the presence of M-CSF (100 ng/mL) with or without a combination of SCF (100 ng/mL), IL-1 (20 ng/mL), and IL-6 (10 ng/mL). Cells were enumerated with a hematocytometer after trypan blue dye exclusion. Error bars indicate standard deviation of cell numbers. *P < .01 compared with M-CSF. Results are representative of three independent experiments.