Functional GM-CSF receptor expression is necessary for accumulation of langerin⁺CD103⁺MHCII^hi DCs in the cutaneous lymph nodes during homeostasis. (A) CD103 and MHCII expression on DCs in lymph nodes from unimmunized WT, β_c^−/−, and GM-CSF^−/− mice, gating on CD11c⁺MHCII⁺ cells. (B) Total number of DC subsets in cutaneous lymph nodes of naive mice (*, P < 0.05; **, P < 0.01; error bars represent SEM). (C) CD45.1/2 expression on langerin⁺CD103⁺MHCII^hi lymph node DCs in unimmunized mixed bone marrow chimeric mice. Irradiated CD45.1⁺ WT hosts were reconstituted with a 1:1 mixture of either CD45.2⁺ WT and CD45.1⁺ WT cells (left) or CD45.2⁺β_c^−/− and CD45.1⁺ WT cells (right). Percentages are shown in A and C. (D) Percentage of cells derived from WT versus β_c^−/− donors within CD11c⁺ lymph node DC subsets from mixed bone marrow chimeras (error bars represent SEM). All data in A–D are representative of three separate experiments with at least three mice per group.