Figure 3. Dermal CD5⁺ DCs are superior to dermal CD5^– DCs at inducing the proliferation and differentiation of Th22 cells.

(A) Proliferation of allogeneic naive CD4⁺ T cells primed with sorted CD40L-activated dermal CD5⁺ or CD5^– CD1a^dim DCs, dermal CD1a^dimCD141⁺, or dermal CD14⁺ DCs was measured after 7 days by CFSE dilution using flow cytometry. The graph shows the frequency of the CFSE^loCD3⁺CD4⁺ T cells (n = 10). Mean ± SD ± SEM for CD5⁺: 39.5% ± 19.8% ± 6.6%, CD5^–: 22.9% ± 17% ± 7.6%, CD141⁺ DCs: 19.5% ± 17% ± 7.6%, CD14⁺ DCs: 5% ± 4.4% ± 1.65%. (B) CFSE-labeled sorted naive CD4⁺ T cells cultured for 6 days with CD40L-activated dermal CD1a^dimCD5⁺ or CD1a^dimCD5^– DCs. CFSE dilution and cytoplasmic expression of IFN-γ and IL-22 were analyzed by flow cytometry after 5-hour stimulation with PMA and ionomycin. (C) The plot shows the frequency of IL-22–producing CD4⁺ T cells that were primed by the different skin DC subsets (n = 10). Top: The plot shows the frequency CD4⁺ T cells that diluted CFSE and express IL-22. Bottom: The plot shows the frequency of IFN-γ and IL-22–producing CFSE^loCD4⁺ T cells. Data are representative of 7 independent experiments. (D) CFSE^loCD4⁺ T cells, primed by either dermal CD1a^dimCD5⁺ or CD5^– DCs, were sorted and restimulated with anti-CD3 and anti-CD28 mAbs for 18 hours. IL-22 and IFN-γ were measured by a Luminex multiplex bead assay (n = 3). One of 3 experiments is shown. Data represent mean ± SEM; **P < 0.01, ***P < 0.005, ****P < 0.0001 by paired Student’s t tests (A and C) or unpaired Student’s t tests (D).