Table 1.
Absence of T-lymphocyte activation by cultured human epidermal keratinocytes (cHEKs)
| Incubation | T lymphocytes activated (%) | |||
|---|---|---|---|---|
| CD69+ | CD25+ | |||
| 4 hr | 24 hr | 48 hr | 72 hr | |
| Cultured HEKs at third passage | ||||
| Control PBMC | 0·8 | 2·1 | 9·1 | 8·7 |
| PBMC + PHA (5 μg/ml) | 14·9 | 88·8 | 15·3 | 21·6 |
| PBMC + cHEK sheets | 0·7 | 1·8 | 12·8 | 10·1 |
| PBMC + cHEKs treated with IFN-γ (20 ng/ml) | 0·9 | 1·9 | 11·9 | 11·3 |
| Cultured HEKs at sixth passage | ||||
| Control PBMC | — | 4·6 | — | — |
| PBMC + PHA (5 μg/ml) | — | 89·0 | — | — |
| PBMC + cHEK sheets | — | 5·1 | — | — |
| PBMC + cHEKs treated with IFN-γ (20 ng/ml) | — | 5·9 | — | — |
PBMC, peripheral blood mononuclear cells; IFN-γ, interferon-γ; PHA, phytohaemagglutinin.
Cultured HEKs were incubated with 1 × 106 PBMC for 4 and 24 hr for CD69, and for 48 and 72 hr for CD25. Control cultures consisted of PBMC stimulated or not with 5 μg/ml PHA. Thereafter, PBMC were harvested and immunostained, and T-cell activation was analysed by flow cytometry.