Differences in the levels of HOXB4 expression between primitive CD34⁺ and differentiated human cells.

Histograms displaying GFP marker expression in human CD34⁺and CD45⁺ cells from 2 of 7 representative HOXB4 versus RFP mice (mice 1 and 2) and from 2 of 6 GFP versus RFP mice (mice 3 and 4) are shown. BM cells were stained with human-specific mAbs against the panleukocyte marker CD45 or the primitive cell marker CD34. Propidium iodide uptake was used for gating viable cells in the first step. Cells positive for human CD34 and CD45 were then gated and analyzed for GFP expression. The mean fluorescence intensity (MFI) values for each GFP⁺ population are indicated in the histograms. In the HOXB4 versus RFP group of mice, differences between primitive CD34⁺ and either CD45⁺ or CD19⁺cells (not shown) in the MFI of GFP were significant (P < .001 and P < .01, respectively).