Fig. 1.

Comparison of cell line characteristics. (A) Box-and-whisker plots of cell line doubling times when grown in RPMI 1640 with serum. (B) Mean doubling times of cell lines. (C) CD38, CD11b and CD14 expression were analyzed by flow cytometry and shown as percent positive cells for each myeloid cell line compared to wild-type (WT) HL60, the bipotent system. Percent positive shift was determined by setting the WT HL60 control to exclude 95% of the population peak. NB4 (p < 0.0001) and U937 (p < 0.05) had significantly higher CD38 expression than WT HL60. All cell lines had similar CD11b expression levels when untreated, but K562 (p < 0.01) and U937 (p < 0.001) had higher CD14 expression compared to WT HL60.