Table 1.
Differentiative Potential of Adult Thymic Epithelial Cells
| Input GFP+ Test Cell Phenotype | No. of Input Cells | Outcome |
|---|---|---|
| Medulla | ||
| UEA1+PLET1+Ly-51−MHCIIlo | 10,000 | no green cells detected, n = 5 |
| UEA1+PLET1−Ly-51−MHCIIlo | 10,000 | 1 small GFP+ medullary area detected in 1 of 2 grafts analyzed |
| UEA1+MHCIIhi | 10,000 | 1 small GFP+ medullary area detected in 1 of 5 grafts |
| Cortex | ||
| Ly-51+UEA1−PLET1− (MHCIIhi and MHCIIlo) | 10,000 | 3/3 grafts, extensive cortical contribution. |
| of 389 GFP+ areas analyzed, 1 was a small mTEC cluster, 1–2 comprised ≤3 atypical K14+ TECs, and the remainder were robust cTEC clusters | ||
| Ly-51+UEA1−PLET1− (MHCIIhi and MHCIIlo) | 400 | contribution to cTECs only (2 clusters), n = 1 |
| Ly-51+UEA1−PLET1−MHCIIhi | 407 | contribution to cTECs only, n = 1 |
| Ly-51+UEA1−PLET1−MHCIIlo | 1,289 | extensive contribution to cTECs, 2 areas containing a few scattered GFP+ cells within a medullary region, n = 1 |
| Unassigned | ||
| Ly-51+UEA1−PLET1+ (MHCIIhi and MHCIIlo/neg) | 1,500 | 3/3 grafts, extensive contribution to both cortex and medulla |
| ∼30% of GFP+ areas were medullary | ||
| 500 | 3/3 grafts, contribution to both cortex and medulla | |
| more than 20 GFP+ areas detected per graft | ||
| mTECs, 37% ± 23.6%, cTECs, 62.6% ± 24.0% of GFP+ clusters | ||
| 250 | 3/3 grafts, contribution to both cortex and medulla | |
| up to 12 GFP+ areas detected per graph | ||
| mTECs, 24% ± 1.4%, cTECs, 76% ± 1.4% of GFP+ clusters | ||
| 125 | 3/3 grafts, contribution to both cortex and medulla | |
| 3–8 GFP+ areas detected per graph | ||
| mTECs, 58% ± 11.3% cTECs, 41.5% ± 12% of GFP+ clusters | ||
| 90 | 1/6 grafts, contribution to both cortex and medulla | |
| 3 GFP+ areas detected | ||
| mTECs, 33% cTECs, 66% of GFP+ clusters | ||
| 60 | 3/3 grafts, no contribution detected | |
| Ly-51+UEA1−PLET1+MHCIIlo/neg | 188–260 | 3/3 grafts, cortical GFP+ areas detected; 1 small atypical K14+ area detected in 1/3 grafts |
| Ly-51+UEA1−PLET1+ MHCIIhi | 129–415 | 3/3 grafts, contribution to both cortex and medulla |
Summary of distribution of GFP+ cells in grafts seeded with the input test cell populations and test cell numbers noted. Grafts were sectioned at 8 μm and every section was collected. Each section was then screened for the presence of GFP+ cells. When foci of GFP+ cells were observed, the sections were stained for mTEC and cTEC markers to determine the identity of the GFP+ cells. GFP+ foci were tracked through sections, with notes taken on the number of sections spanned and the position of foci in the graft relative to other GFP+ foci. n is shown for each population tested and represents the number of independent grafts analyzed. Statistical data show mean ± SD for proportion of GFP+ clusters in cortical and medullary regions across all grafts analyzed for a given condition. One-way ANOVA showed no significant difference in distribution of GFP+ clusters among grafts seeded with 500, 250, or 125 cells (medullary contribution, p = 0.076, cortical contribution, p = 0.087).
See also Table S2.