Table 1.
Naïve T cells selectively enter the aged thymus
| Organ | Host mice | Donor CD8 SP GFP− cells |
Mean no. of donor cells ± SD | |
|---|---|---|---|---|
| % | No. | |||
| Thymus | Young | 0.16–2.0 | 0.1–1.3 × 103 | 6.1 ± 4.7 × 102 |
| Old | 4.7–12.4 | 3.6–9.3 × 103 | 6.5 ± 2.5 × 103 | |
| Spleen | Young | 5.4–11.3 | 2.3–8.4 × 105 | 4.8 ± 2.9 × 105 |
| Old | 5.4–11.6 | 4.0–7.8 × 105 | 5.8 ± 1.8 × 105 | |
Naïve CD8+ T cells from 8-week-old OT-1 TCR Tg Ly5.1 mice were injected into six young (8- to 10-week-old) and five aged (70- to 76-week-old) Ly5.2 congenic RAG2p-GFP Tg hosts. Recipient thymocytes and splenocytes were analyzed for donor cells 4 days after adoptive transfer by staining for Ly5.1, CD4, CD8, CD44, and CD62L surface expression. The donor cells remain CD44low and CD62Lhi. The percentages and number of donor cells among CD8 SP GFP− cells in each organ were tabulated. P = 0.00033 comparing the number of donor cells in the old and young thymuses; P = 0.513 comparing the number of donor cells in the old and young spleens (two-tailed Student t test with equal variance).