Growth and differentiation characteristics of parental 32Dcl3, 32Dneo, and 32DHOX-B8 cells in the presence of IL-3 or G-CSF. (A) Growth kinetics in culture medium supplemented with either IL-3 (10% WEHI-3B conditioned medium), no supplements (−IL-3), or G-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. An enlarged copy of each of the regions demarcated by a box is shown above the appropriate curve for −IL-3 and +G-CSF. (B) DNA fragmentation analysis in parental 32Dcl3 and 32DHOX-B8 in the presence of IL-3, after IL-3 withdrawal for 24 hours, and after treatment with G-CSF for indicated times. (C) Photomicrographs (original magnification × 400) of 32Dneo and 32DHOX-B8 cells stained with May-Grünwald-Giemsa in the presence of IL-3, or following treatment with G-CSF (9 days for 32Dneo and 2 days for 32DHOX-B8). (D) G-CSFR expression in 32Dneo and 32DHOX-B8 clones. Analysis was done by RT-PCR as described in Materials and Methods. 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, in which data are presented for 32Dneo clone 3 and 32DHOX-B8 clone 18, unless otherwise indicated. Parental and all 32Dneo clones examined behaved similarly.