Functional Specializations of Human Epidermal Langerhans Cells and CD14+ Dermal Dendritic Cells

SummaryLittle is known about the functional differences between the human skin myeloid dendritic cell (DC) subsets, epidermal CD207+ Langerhans cells (LCs) and dermal CD14+ DCs. We showed that CD14+ DCs primed CD4+ T cells into cells that induce naive B cells to switch isotype and become plasma cells. In contrast, LCs preferentially induced the differentiation of CD4+ T cells secreting T helper 2 (Th2) cell cytokines and were efficient at priming and crosspriming naive CD8+ T cells. A third DC population, CD14−CD207−CD1a+ DC, which resides in the dermis, could activate CD8+ T cells better than CD14+ DCs but less efficiently than LCs. Thus, the human skin displays three DC subsets, two of which, i.e., CD14+ DCs and LCs, display functional specializations, the preferential activation of humoral and cellular immunity, respectively.