Skin-dependent regulation of CCR8 expression is independent of vitamins A and D. (A) Purified allogeneic naive T cells were cocultured for 9 days with MACS-enriched epidermal LCs, dermal CD1a⁺ DCs, or dermal CD14⁺ DCs at a ratio of 10:1 in media alone or media supplemented with 200nM RA or 2μM LE540. The percentage of T cells expressing CCR8, CCR10, CCR9, or CXCR3 was determined by flow cytometry. Data are plotted as mean ± SEM from 3 independent experiments. (B-C) Naive T cells were stimulated with αCD3/CD28 beads for 6 days in the presence of KCM (C) or a submersed monolayer of primary keratinocytes, untreated or treated with either 100nM 1,25-(OH)₂D₃ ± 12.5 ng/mL IL-12 (B) or 2μM LE540 (C). The percentage of total CD3⁺ T cells expressing CCR8, CCR9, CCR10, or CLA was determined by flow cytometry. Data are plotted as the mean ± SD (n = 4-7) from 3 independent experiments. *P < .05. **P < .01. ***P < .001.