title: Schistosoma mansoni worm glycolipids induce an inflammatory phenotype in human dendritic cells by cooperation of TLR4 and DC-SIGN.
abstract: In schistosomiasis, a major human parasitic disease caused by helminths, different life-stages of the parasite contribute to the developing host immune response. To increase our understanding of the mechanisms that play a role in shaping the host immune responses, we have investigated the effects of schistosome glycoconjugates on the phenotype of dendritic cells (DCs), which form a crucial link between the innate and the adaptive immunity. We show here that Schistosoma mansoni worm glycolipids induce DC activation as indicated by upregulation of the maturation markers CD80, CD86 and MHC-II, as well as the production of the cytokines interleukin-12 p40 (IL-12 p40), IL-10, IL-1beta, IL-6, IL-8 and tumor necrosis factor-alpha (TNF-alpha). Co-culture of glycolipid-primed DCs with naïve T cells results in skewing of the T cell response towards a Th1 profile. Remarkably, the DC activation is dependent on fucosylated glycan moieties of the glycolipids. On the DCs, the C-type lectin DC-SIGN and TLR4 are both critically involved in the induced activation, as was demonstrated by using monoclonal antibodies that block interaction of these receptors with the glycolipids. Furthermore, whereas the worm glycolipids were not able to activate HEK 293 cells expressing TLR4, they did show TLR4 activation after introduction of DC-SIGN in the HEK 293-TLR4 cells. Our data provide evidence for a novel function of DC-SIGN as an essential co-receptor for TLR4-induced activation of human DCs. This mechanism of TLR4 activation by worm glycolipids may contribute to eliciting Th1 immune responses in schistosome infection.
authors.affiliation: VU University Medical Center, Van den Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
authors.forename: Caroline M W
authors.initials: CM
authors.lastname: van Stijn
authors.forename: Sandra
authors.initials: S
authors.lastname: Meyer
authors.forename: Marloes
authors.initials: M
authors.lastname: van den Broek
authors.forename: Sven C M
authors.initials: SC
authors.lastname: Bruijns
authors.forename: Yvette
authors.initials: Y
authors.lastname: van Kooyk
authors.forename: Rudolf
authors.initials: R
authors.lastname: Geyer
authors.forename: Irma
authors.initials: I
authors.lastname: van Die
mesh_terms: D000818:Animals; D015815:Cell Adhesion Molecules / Q000276:immunology*; D002454:Cell Differentiation; D002460:Cell Line; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D005643:Fucose / Q000378:metabolism; D006017:Glycolipids / Q000276:immunology*; D006801:Humans; D007249:Inflammation / Q000276:immunology; D037181:Lectins, C-Type / Q000276:immunology*; D010641:Phenotype; D011956:Receptors, Cell Surface / Q000276:immunology*; D012550:Schistosoma mansoni / Q000276:immunology*; D051197:Toll-Like Receptor 4 / Q000276:immunology*; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D015815:Cell Adhesion Molecules; D005643:Fucose; D006017:Glycolipids; D037181:Lectins, C-Type; D011956:Receptors, Cell Surface; D051197:Toll-Like Receptor 4; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin; C495345:TLR4 protein, human