HSC trafficking in marrow, spleen and blood under basal conditions
Parabiosis, wk . | Pairs, n . | Granulocytes, % partner ± SD . | CFU-GMs, % partner ± SD . | HSCs, % partner ± SD . |
|---|---|---|---|---|
| Marrow | ||||
| 3 | 3 | 2.3 ± 0.6 | 2.4 ± 0.4 | 1.0 ± 0.8 |
| 6 | 3 | 2.9 ± 0.1 | 3.5 ± 1.4 | 1.4 ± 0.4 |
| 8 | 1 | 5.4 ± 2.0 | 9.6 ± 1.2 | 2.5 ± 3.0 |
| 12 | 2 | 3.8 ± 0.8 | 5.5 ± 0.9 | 1.2 ± 0.5 |
| Spleen | ||||
| 3 | 3 | 43.3 ± 10.0 | 46.0 ± 11.4 | 2.4 ± 2.4 |
| 6 | 2 | 38.0 ± 11.2 | 47.2 ± 2.5 | 1.5 ± 1.3 |
| 8 | 1 | NT | 49.1 ± 8.8 | 2.0 ± 0.5 |
| 12 | 2 | 55.3 ± 0.8 | 46.8 ± 2.7 | 3.6 ± 5.5 |
| Blood | ||||
| 3 | 6 | 39.3 ± 9.3 | 42.1 ± 7.7 | NR |
| 6 | 1 | 41.8 ± 6.6 | 41.8 ± 4.8 | NR |
Parabiosis, wk . | Pairs, n . | Granulocytes, % partner ± SD . | CFU-GMs, % partner ± SD . | HSCs, % partner ± SD . |
|---|---|---|---|---|
| Marrow | ||||
| 3 | 3 | 2.3 ± 0.6 | 2.4 ± 0.4 | 1.0 ± 0.8 |
| 6 | 3 | 2.9 ± 0.1 | 3.5 ± 1.4 | 1.4 ± 0.4 |
| 8 | 1 | 5.4 ± 2.0 | 9.6 ± 1.2 | 2.5 ± 3.0 |
| 12 | 2 | 3.8 ± 0.8 | 5.5 ± 0.9 | 1.2 ± 0.5 |
| Spleen | ||||
| 3 | 3 | 43.3 ± 10.0 | 46.0 ± 11.4 | 2.4 ± 2.4 |
| 6 | 2 | 38.0 ± 11.2 | 47.2 ± 2.5 | 1.5 ± 1.3 |
| 8 | 1 | NT | 49.1 ± 8.8 | 2.0 ± 0.5 |
| 12 | 2 | 55.3 ± 0.8 | 46.8 ± 2.7 | 3.6 ± 5.5 |
| Blood | ||||
| 3 | 6 | 39.3 ± 9.3 | 42.1 ± 7.7 | NR |
| 6 | 1 | 41.8 ± 6.6 | 41.8 ± 4.8 | NR |
Phenotypes of granulocytes, CFU-GMs, and HSCs in marrow, spleen, and blood were assessed after 3, 6, 8, and 12 weeks of parabiosis. See “Results” for details. Although blood cells from 2 ROSA or 2 PeP3b parabionts were pooled before secondary transplantation, recipient animals either failed to reconstitute hematopoiesis and died within 14 days of irradiation or recovered with 97% or more endogenous cells, implying that few HSCs circulate during normal homeostasis. NT indicates not tested; NR, no reconstitution of irradiated recipients.