Summary of DNA analysis (A) and frequency of human CFC (B) in the BM of NOD/SCID mice receiving transplants of freshly isolated BM cells and those isolated after 1 and 2 weeks of culture on stroma. Each symbol represents the level of engraftment (A) or CFC concentration (B) in a single mouse. Solid symbols represent mice receiving transplants of cultured cells treated with trypsin. Open symbols represent mice receiving transplants of cells treated with CDB. The horizontal lines indicate the mean level of engraftment. *Statistically significant differences (P < .05) in the mean levels of engraftment in mice injected with 10 × 106 cells cultured for 1 and 2 weeks compared with fresh BM cells. **Statistically significant differences in the mean levels of engraftment in mice injected with 20 × 106 cells after 1 and 2 weeks of coculture (P < .01 and P < .05, respectively) compared with 20 × 106 uncultured BM cells.
