Growth and differentiation characteristics of parental 32Dcl3, 32Dneo, and 32DHOX-B8 cells in the presence of GM-CSF. (A) Growth kinetics in culture medium supplemented with GM-CSF (10 ng/mL). Cells were seeded as indicated in Materials and Methods, and viable cell numbers were determined by trypan blue dye exclusion, with counting in a hemocytometer. (B) Photomicrographs (original magnification × 400) of 32Dneo and 32DHOX-B8 in the presence of GM-CSF for 10 days. (C) Egr-1 expression in 32Dneo, 32DHOX-B8, and 32DEgr-1 (clone 2) cells. Analysis was performed by Northern blots, using 10 μg of total RNA per lane. In all cases, three 32Dneo clones (clones 3, 7, and 11) and five 32DHOX-B8 clones (clones 4, 6, 8, 9, and 18) were examined; data are presented for 32Dneo clone 3 and 32DHOX-B8 clone 18, unless otherwise indicated. Parental and all 32Dneo clones examined behaved similarly.