Figure 4.

Role of CXCR-4 in repopulating activity and homing of fresh or expanded CD34⁺ cells in NOD/SCID β₂m-null mice. (A) Mice were transplanted with 100–150×10³ CD34⁺ cells or their expansion equivalent after a 3-day expansion culture. Prior to infusion, cells were incubated with function-blocking anti-CXCR4 12G5 monoclonal antibody or anti-CD34 as control. Bone marrow chimerism was determined after 6 weeks by staining with human-specific anti-CD45. Solid symbols indicate the mean ± SEM engraftment levels in each experimental condition. (B) Mice were infused with 500×10³ fresh or 500×10³ expanded CD34⁺ cells. Homed CD34⁺ cells were measured in bone marrow of recipient mice 16–20 hours later. *p<0.05 compared to transplantation of control cells (n=3 experiments with two to four mice in each condition).