HSC yields are reduced in cultures containing a low concentration of SF
| Cytokine condition . | Dose of cells injected* . | No. of positive mice/no. of mice tested . | No. of HSCs detected after 10 days (± SEM)† . |
|---|---|---|---|
| 300 ng/mL SF | 7 | 5/5 | 27 |
| + 20 ng/mL IL-11 | 2 | 3/8 | (19-39) |
| 0.7 | 0/6 | ||
| 10 ng/mL SF | 7 | 1/5 | 2 |
| + 20 ng/mL IL-11 | 2 | 0/5 | (0.8-6) |
| 0.7 | 0/3 |
| Cytokine condition . | Dose of cells injected* . | No. of positive mice/no. of mice tested . | No. of HSCs detected after 10 days (± SEM)† . |
|---|---|---|---|
| 300 ng/mL SF | 7 | 5/5 | 27 |
| + 20 ng/mL IL-11 | 2 | 3/8 | (19-39) |
| 0.7 | 0/6 | ||
| 10 ng/mL SF | 7 | 1/5 | 2 |
| + 20 ng/mL IL-11 | 2 | 0/5 | (0.8-6) |
| 0.7 | 0/3 |
Each dose of transplanted cells was sampled from a large pool of 10-day clones generated in either 300 ng/mL or 10 ng/mL SF in combination with 20 ng/mL IL-11. The cell doses are expressed as “starting equivalents” (day 0 = ∼ 30 HSCs). Because each experiment was initiated with 100 starting cells, a cell dose of 7 represents 7% of all the cells from the pooled clones.
L-Calc software (StemCell Technologies) was used to calculate the mean frequency of HSCs in the pooled 10-day clones from limiting dilution transplant results. The starting HSC frequency (3/10 = 30%) was determined from single-cell transplants of freshly isolated CD45midlin−Rho−SP cells.