Table 7.
Frequencies of CD34−KSL Cells among Bone Marrow Cells
| Age of mice | |||
|---|---|---|---|
| Cells | 2 mo | 18 mo | Fold increase |
| Total CD34−KSL cells | 5 | 87 | 17.4 |
| HSCs | 1.6 | 3.8 | 2.2 |
| Defective HSCs | <0.5 | 2.9 | >5.8 |
| Progenitor cells | 1.9 | 60.0 | 31.6 |
| Unidentified cells | 1.0 | 20.3 | 20.3 |
The number of cells per 105 bone marrow cells is shown. The fold increase from 2 to 18 mo of age is also shown. The frequency of total CD34−KSL cells in bone marrow cells was obtained by FACS® analysis. Frequencies of HSCs, defective HSCs, and progenitor cells among CD34−KSL cells were estimated using functional assays. Proceeding from the assumption that all HSCs and defective HSCs have colony-forming ability in vitro, the numbers of colony-forming cells without repopulating activity were calculated; these cells were classified as myeloid progenitors. Cells without colony-forming and repopulating ability are shown as unidentified cells.