Summary of long-term competitive repopulating ability of subsets of pluripotent hematopoietic stem cells (PHSC)
| PHSC subset . | Competitor cells: 2 × 105 WBM cells . | Competitor cells: 4 × 105 WBM cells . | ||
|---|---|---|---|---|
| 45 donor cells . | 100 donor cells . | 10 donor cells . | 100 donor cells . | |
| 38+34− | 22.5 ± 6.4 | 53.6 ± 10 | 4.3 ± 0.9 | 19.1 ± 3.3 |
| RU = 1.3 (12; 100%) | RU = 2.3 (9; 100%) | RU = 1.8 (29; 79%) | RU = 0.9 (30; 100%) | |
| 38+34+ | 0.7 | 3.0 ± 0.6 | 0.8 ± 0.09 | 5.8 ± 1.8 |
| RU = 0.03 (5; 20%) | RU = 0.06 (8; 100%) | RU = 0.3 (22; 13%) | RU = 0.25 (22; 77%) | |
| 38−34+ | Background | 3.9 ± 1 | 0.9 ± 0.2 | 0.7 ± 0.06 |
| RU = 0 (5; 0%) | RU = 0.08 (10; 90%) | RU = 0.39 (18; 11%) | RU = 0.03 (29; 30%) | |
| 38−34− | Not determined | Not determined | 0.7 ± 0.2 | Not determined |
| RU = 0.28 (18; 11%) | ||||
| PHSC subset . | Competitor cells: 2 × 105 WBM cells . | Competitor cells: 4 × 105 WBM cells . | ||
|---|---|---|---|---|
| 45 donor cells . | 100 donor cells . | 10 donor cells . | 100 donor cells . | |
| 38+34− | 22.5 ± 6.4 | 53.6 ± 10 | 4.3 ± 0.9 | 19.1 ± 3.3 |
| RU = 1.3 (12; 100%) | RU = 2.3 (9; 100%) | RU = 1.8 (29; 79%) | RU = 0.9 (30; 100%) | |
| 38+34+ | 0.7 | 3.0 ± 0.6 | 0.8 ± 0.09 | 5.8 ± 1.8 |
| RU = 0.03 (5; 20%) | RU = 0.06 (8; 100%) | RU = 0.3 (22; 13%) | RU = 0.25 (22; 77%) | |
| 38−34+ | Background | 3.9 ± 1 | 0.9 ± 0.2 | 0.7 ± 0.06 |
| RU = 0 (5; 0%) | RU = 0.08 (10; 90%) | RU = 0.39 (18; 11%) | RU = 0.03 (29; 30%) | |
| 38−34− | Not determined | Not determined | 0.7 ± 0.2 | Not determined |
| RU = 0.28 (18; 11%) | ||||
Individual subsets were isolated by 5-color fluorescence-activated cell sorting (FACS). Then, 10, 45, or 100 Ly5.1 donor cells and the indicated number of Ly5.2 whole bone marrow (WBM) competitor cells were injected into lethally irradiated Ly5.2 mice. Peripheral blood (PB) was collected at various times during the next 12 months and examined for engraftment of Ly5.1 donor cells. Only the data from 12 months after bone marrow transplantation (BMT) are shown. The frequency of the subsets of PHSC in the WBM was 2.2 cells/100 000 cells for 38+34−, 5.1 cells/100 000 cells for 38+34+, 15.0 cells/100 000 cells for 38−34+, and 0.83 cells/100 000 cells for 38−34−. Plus-minus values are the mean ± SE percentages of donor cells in total PB cells (ie, the donor-cell contribution). RU indicates repopulating units as defined by Jordan et al.22 An RU is the repopulating-ability equivalent to 100 000 untreated BM cells from adults and is calculated, for 100 cells, according to the following equation: donor RU = (% donor cells × competitor RU)/(100 − % donor cells). The RU of competitor cells here is 2 or 4 (there is 1 RU/100 000 WBM cells). The mean values for donor RU for the 3 subsets of PHSC studied were 1.6 for 38+34−, 0.16 for 38+34+, and 0.12 for 38−34+. The values in parentheses are the number of mice in each experiment and the percentage of engraftment. The data are from 8 independent experiments.