Comparison of the frequency of SRCs by limiting dilution assay
| Route . | No. cells injected . | No. engrafted mice . | No. transplantations . |
|---|---|---|---|
| iBM | 10 000 | 2 | 2 |
| 1 000 | 6 | 6 | |
| 500 | 4 | 4 | |
| 250 | 5 | 5 | |
| 100 | 8 | 10 | |
| 50 | 7 | 12 | |
| 10 | 5 | 10 | |
| 5 | 2 | 9 | |
| Intravenous | 10 000 | 2 | 2 |
| 5 000 | 5 | 5 | |
| 2 000 | 3 | 4 | |
| 500 | 3 | 5 | |
| 100 | 2 | 5 | |
| 50 | 1 | 5 |
| Route . | No. cells injected . | No. engrafted mice . | No. transplantations . |
|---|---|---|---|
| iBM | 10 000 | 2 | 2 |
| 1 000 | 6 | 6 | |
| 500 | 4 | 4 | |
| 250 | 5 | 5 | |
| 100 | 8 | 10 | |
| 50 | 7 | 12 | |
| 10 | 5 | 10 | |
| 5 | 2 | 9 | |
| Intravenous | 10 000 | 2 | 2 |
| 5 000 | 5 | 5 | |
| 2 000 | 3 | 4 | |
| 500 | 3 | 5 | |
| 100 | 2 | 5 | |
| 50 | 1 | 5 |
NOD/SCID mice (n = 84) were transplanted with various numbers of Lin−/low CD34+CD38− CB cells by iBM or intravenous injection. Engraftment in murine BM was analyzed at 8 weeks. Mice were considered to be engrafted when they were determined positive by both FACS and PCR analysis. The frequency of engrafting cells in CB Lin−/lowCD34+CD38− cells transplanted by iBM and intravenously was found to be 1 in 44 Lin−/lowCD34+CD38− cells (95% confidence limits, 1 in 27 to 1 in 70) and 1 in 660 Lin−/lowCD34+CD38− cells (95% confidence limits, 1 in 289 to 1 in 1510), respectively. SRC frequencies were calculated using Poisson statistics and the method of maximum likelihood with the assistance of the L-Calc software (StemCell Technologies).