title: Mixed Langerhans cell and interstitial/dermal dendritic cell subsets emanating from monocytes in Th2-mediated inflammatory conditions respond differently to proinflammatory stimuli.
abstract: The skin harbors two dendritic cell (DC) subsets, Langerhans cells (LC) and interstitial/dermal DC (IDDC), which traffic to lymph nodes after inflammation and ultraviolet stress. To demonstrate that monocytes may act as DC precursors for skin DC in postinflammatory recolonization, we generated LC and IDDC from monocytes by using cytokines related to the T helper cell type 2 environment [granulocyte macrophage-colony stimulating factor/transforming growth factor-beta/interleukin-13/tumor necrosis factor alpha (GM-CSF/TGF-beta/IL-13/TNF-alpha)]. In this study, skin DC [LC as Langerin/CD207(+) cells and IDDC as DC-specific intercellular adhesion molecule-grabbing nonintegrin (SIGN)/CD209(+) cells] displayed desynchronized programs along their differentiation, activation/maturation processes in response to stimuli characteristics of a proinflammatory context. First, we demonstrate that monocytes are able to diverge simultaneously along two distinct pathways toward Langerin(+)-LC-type DC and DC-SIGN(+)-IDDC. Second, as TGF-beta is known to antagonize the TNF-alpha-induced maturation process of DC, we showed that IDDC did not mature and acquired a low CC chemokine receptor 7 (CCR7) receptor expression even when stimulated with prolonged incubation with TNF-alpha. It is striking that the LC subset is able to express a high level of CCR7 expression and the maturation marker DC-lysosome-associated membrane protein (DC-LAMP). Third, mixed LC and IDDC subsets secrete IL-10 and IL-12 when stimulated by CD40 ligand and lipopolysaccharide (LPS) but not after prolonged incubation with TNF-alpha. In contrast, LPS was a better activator of IL-10 secretion than the CD40 ligand for GM-CSF/IL-4-generated DC and for GM-CSF/TGF-beta/IL-13-generated LC and IDDC populations. To summarize, the phenotypic/migratory maturation status of LC may be more easily enhanced by stimuli mimicking a proinflammatory situation, and IDDC are more resistant. Moreover, our culture system provided a means of studying cross-talk between two skin DC outside of their respective skin compartment.
authors.affiliation: INSERM Unit 346, Human Skin and Immunity, EA No. 37-32, Claude Bernard University Lyon 1, Edouard Herriot Hospital, 69437 Lyon Cedex 03, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Bechetoille
authors.forename: Valérie
authors.initials: V
authors.lastname: André
authors.forename: Jenny
authors.initials: J
authors.lastname: Valladeau
authors.forename: Eric
authors.initials: E
authors.lastname: Perrier
authors.forename: Colette
authors.initials: C
authors.lastname: Dezutter-Dambuyant
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D016179:Granulocyte Colony-Stimulating Factor / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000276:immunology; D007801:Langerhans Cells / Q000276:immunology*; D018950:Lipopolysaccharide Receptors / Q000276:immunology; D016173:Macrophage Colony-Stimulating Factor / Q000276:immunology; D051379:Mice; D009000:Monocytes / Q000276:immunology*; D010641:Phenotype; D018418:Th2 Cells / Q000276:immunology*; D046509:Tissue Culture Techniques; D016212:Transforming Growth Factor beta / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
chemical_list: D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D016179:Granulocyte Colony-Stimulating Factor; D016173:Macrophage Colony-Stimulating Factor