Growth advantage in human CD34⁺ cells overexpressing HOXB4.

Human CD34⁺ cells overexpressing HOXB4 have a marked competitive growth advantage in NOD/SCID mice receiving transplants. (A) FACS analysis of human CD34⁺ cells expressing either GFP (top) or RFP (bottom) in marrow samples from mice that had received transplants with equal initial cell inoculums containing either HOXB4 (FMEV-HAHOXB4wPRE)– and RFP-transduced cells in a 1:2 ratio (HOXB4 versus RFP), or GFP- and RFP-transduced cells in a 1:1 ratio (GFP versus RFP). (B) In all mice receiving competitive transplants of HOXB4 versus RFP, HOXB4⁺(GFP⁺)CD34⁺ cells clearly dominated over RFP⁺CD34⁺ cells 8 weeks after transplantation. In contrast, in 3 of 6 mice of the GFP versus the RFP control group, RFP⁺CD34⁺cells predominated over GFP⁺CD34⁺ cells, whereas in the other 3 mice we observed the reverse.