Relationship between cell dose and engraftment.

The degree of cell engraftment in NOD/SCID mice is proportional to the number of transplanted human CD34⁺ cells. A cell–dose-limiting dilution experiment into NOD/SCID mice shows a linear relationship between cell dose and engraftment levels. Lentivirally transduced CD34⁺ cells were transplanted into NOD/SCID recipients and the bone marrow mononuclear cells analyzed 6 weeks later by FACS using antibodies directed against human CD45 to detect human cells. Four mice underwent transplantation with the following cell doses and the percentage of CD45⁺ cell plotted against cell dose: 400 000, 100 000, 35 000, 12 500, and 5000.