Langerin⁺CD103⁺MHCII^hi dermal DCs are GM-CSF dependent. (A) FACS analysis of dermal mononuclear cells from naive WT and GM-CSF^−/− mice. Dot plots are gated on total MHCII⁺ (left) or langerin⁺MHCII⁺ cells (right). (B) Epidermal mononuclear cells from naive WT and GM-CSF^−/− mice. Histograms are gated on MHCII⁺ cells. Shaded histograms indicate isotype control staining. Dot plots (right) are gated on langerin⁺ epidermal cells. (C) Immunofluorescent staining for langerin (green) and CD103 (red) in ear skin sections from WT and GM-CSF^−/− mice. The epidermis lies above the dermis in each image. (D) CD45.2 expression on CD11b⁺CD103⁻MHCII⁺ (left) and CD11b⁻CD103⁺MHCII⁺ (right) dermal cells from mixed bone marrow chimeric mice reconstituted with a 1:1 mixture of CD45.2β_c^−/− and CD45.1 WT bone marrow cells. (E) Percentage of TRITC⁺ cells among the langerin⁺CD11c⁺CD103⁺ (left) and CD103⁻ (right) subsets of auricular lymph node cells in WT and GM-CSF^−/− mice on days 2, 4, and 7 after ear painting (*, P < 0.05; error bars represent SEM). All data shown are representative of two to four experiments with at least three mice per group. Percentages are shown in A, B, and D. Bars, 10 µm.