Determination of the number of intravenously transplanted young CRUs that home to the BM of old irradiated mice
. | Negative mice* . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| Cell type injected . | 5 wk . | 10 wk . | 17 wk . | 26 wk . | |||
| Fresh young BM¶ | |||||||
| 2 × 103 | 15 of 16 | 15 of 16 | 16 of 16 | 16 of 16 | |||
| 6 × 103 | 12 of 16 | 12 of 16 | 12 of 16 | 12 of 16 | |||
| 2 × 104 | 3 of 15 | 4 of 15 | 7 of 15 | 7 of 14 | |||
| 6 × 104 | 0 of 8 | 0 of 8 | 0 of 8 | 0 of 8 | |||
| 1/CRU frequency† (±SEM) | 15242 (12 124 ∼ 19 163) | 16 814 (13 350 ∼ 21 178) | 23 608 (18 571 ∼ 30 012) | 24 578 (19 232 ∼ 31 409) | |||
| No. CRUs injected‡ (±SEM) | 197 (157 ∼ 247) | 178 (142 ∼ 225) | 127 (100 ∼ 162) | 122 (96 ∼ 156) | |||
| Homed young BM¶ | |||||||
| 0.005 | 8 of 8 | 8 of 8 | 7 of 7 | 7 of 7 | |||
| 0.014 | 13 of 14 | 13 of 13 | 13 of 13 | 13 of 13 | |||
| 0.042 | 11 of 14 | 10 of 14 | 11 of 14 | 9 of 11 | |||
| 0.125 | 7 of 14 | 6 of 14 | 8 of 14 | 8 of 14 | |||
| CRU frequency, 1 per primary BM fraction (±SEM)§ | 0.182 (0.134 ∼ 0.247) | 0.159 (0.119 ∼ 0.213) | 0.231 (0.166 ∼ 0.32) | 0.247 (0.174 ∼ 0.352) | |||
| 1/CRU frequency, no. CRUs recovered per primary BM (±SEM)∥ | 5.5 (4 ∼ 7.5) | 6.3 (4.7 ∼ 8.4) | 4.3 (3.1 ∼ 6.0) | 4.0 (2.8 ∼ 5.7) | |||
. | Negative mice* . | . | . | . | |||
|---|---|---|---|---|---|---|---|
| Cell type injected . | 5 wk . | 10 wk . | 17 wk . | 26 wk . | |||
| Fresh young BM¶ | |||||||
| 2 × 103 | 15 of 16 | 15 of 16 | 16 of 16 | 16 of 16 | |||
| 6 × 103 | 12 of 16 | 12 of 16 | 12 of 16 | 12 of 16 | |||
| 2 × 104 | 3 of 15 | 4 of 15 | 7 of 15 | 7 of 14 | |||
| 6 × 104 | 0 of 8 | 0 of 8 | 0 of 8 | 0 of 8 | |||
| 1/CRU frequency† (±SEM) | 15242 (12 124 ∼ 19 163) | 16 814 (13 350 ∼ 21 178) | 23 608 (18 571 ∼ 30 012) | 24 578 (19 232 ∼ 31 409) | |||
| No. CRUs injected‡ (±SEM) | 197 (157 ∼ 247) | 178 (142 ∼ 225) | 127 (100 ∼ 162) | 122 (96 ∼ 156) | |||
| Homed young BM¶ | |||||||
| 0.005 | 8 of 8 | 8 of 8 | 7 of 7 | 7 of 7 | |||
| 0.014 | 13 of 14 | 13 of 13 | 13 of 13 | 13 of 13 | |||
| 0.042 | 11 of 14 | 10 of 14 | 11 of 14 | 9 of 11 | |||
| 0.125 | 7 of 14 | 6 of 14 | 8 of 14 | 8 of 14 | |||
| CRU frequency, 1 per primary BM fraction (±SEM)§ | 0.182 (0.134 ∼ 0.247) | 0.159 (0.119 ∼ 0.213) | 0.231 (0.166 ∼ 0.32) | 0.247 (0.174 ∼ 0.352) | |||
| 1/CRU frequency, no. CRUs recovered per primary BM (±SEM)∥ | 5.5 (4 ∼ 7.5) | 6.3 (4.7 ∼ 8.4) | 4.3 (3.1 ∼ 6.0) | 4.0 (2.8 ∼ 5.7) | |||
Lethally irradiated old (20-22 months of age) Ly-5.1 mice were injected with 3 × 106 BM cells from young (6-8 weeks of age) Ly-5.2 mice, and their marrow was harvested 24 hours later. Frequencies of CRUs in this primary BM and in the B6 suspension injected initially were determined by transplanting graded numbers of fresh or homed BM cells into separate sets of lethally irradiated Ly-5.1 recipients analyzed for donor (Ly-5.2+)-derived engraftment at the indicated times. Pooled data are from 2 independent experiments.
Negative mice are defined as animals in which less than 5% of the circulating B or T lymphocytes or myeloid cells, or any combination of them, were derived from donor (Ly-5.2+) stem cells at the time of analysis. Values for fresh young BM and homed young BM are proportions.
Shown are the number of BM cells containing one CRU. The range in CRU frequencies defined by ± 1 SEM is shown in parentheses.
Absolute values were determined by multiplying 1/CRU frequency (†) by 3 × 106 cells, the number of fresh cells injected into primary recipients.
Frequencies of homed CRUs are expressed as the proportion of primary BM cells that contain one CRU.
Absolute numbers of CRUs that homed to the total primary BM was determined by inverting the frequencies of homed CRUs (§).
No. fresh cells or fraction of homed primary BM injected per mouse.