title: Fc gamma RIIB regulates nasal and oral tolerance: a role for dendritic cells.
abstract: Mucosal tolerance prevents the body from eliciting productive immune responses against harmless Ags that enter the body via the mucosae, and is mediated by the induction of regulatory T cells that differentiate in the mucosa-draining lymph nodes (LN) under defined conditions of Ag presentation. In this study, we show that mice deficient in FcgammaRIIB failed to develop mucosal tolerance to OVA, and demonstrate in vitro and in vivo a critical role for this receptor in modulating the Ag-presenting capacity of dendritic cells (DC). In vitro it was shown that absence of FcgammaRIIB under tolerogenic conditions led to increased IgG-induced release of inflammatory cytokines such as MCP-1, TNF-alpha, and IL-6 by bone marrow-derived DC, and increased their expression of costimulatory molecules, resulting in an altered immunogenic T cell response associated with increased IL-2 and IFN-gamma secretion. In vivo we could show enhanced LN-DC activation and increased numbers of Ag-specific IFN-gamma-producing T cells when FcgammaRIIB(-/-) mice were treated with OVA via the nasal mucosa, inferring that DC modulation by FcgammaRIIB directed the phenotype of the T cell response. Adoptive transfer of CD4(+) T cells from the spleen of FcgammaRIIB(-/-) mice to naive acceptor mice demonstrated that OVA-responding T cells failed to differentiate into regulatory T cells, explaining the lack of tolerance in these mice. Our findings demonstrate that signaling via FcgammaRIIB on DC, initiated by local IgG in the mucosa-draining LN, down-regulates DC activation induced by nasally applied Ag, resulting in those defined conditions of Ag presentation that lead to Tr induction and tolerance.
authors.affiliation: Department of Molecular Cell Biology and Immunology, Vrije Universiteit Medical Center, Faculteit der Geneeskunde, MB Amsterdam, The Netherlands. j.samsom@erasmusmc.nl
authors.forename: Janneke N
authors.initials: JN
authors.lastname: Samsom
authors.forename: Lisette A
authors.initials: LA
authors.lastname: van Berkel
authors.forename: Joop M L M
authors.initials: JM
authors.lastname: van Helvoort
authors.forename: Wendy W J
authors.initials: WW
authors.lastname: Unger
authors.forename: Wendy
authors.initials: W
authors.lastname: Jansen
authors.forename: Theo
authors.initials: T
authors.lastname: Thepen
authors.forename: Reina E
authors.initials: RE
authors.lastname: Mebius
authors.forename: Sjef S
authors.initials: SS
authors.lastname: Verbeek
authors.forename: Georg
authors.initials: G
authors.lastname: Kraal
mesh_terms: D000281:Administration, Intranasal; D019264:Adoptive Transfer; D000818:Animals; D017951:Antigen Presentation / Q000235:genetics / Q000276:immunology; D015703:Antigens, CD / Q000235:genetics / Q000502:physiology*; D001854:Bone Marrow Cells / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D007108:Immune Tolerance; D008198:Lymph Nodes / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009061:Mouth Mucosa / Q000276:immunology* / Q000378:metabolism*; D009297:Nasal Mucosa / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D010047:Ovalbumin / Q000008:administration & dosage / Q000276:immunology; D017452:Receptors, IgG / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology / Q000637:transplantation; D050378:T-Lymphocytes, Regulatory / Q000276:immunology / Q000473:pathology
chemical_list: D015703:Antigens, CD; C080571:Fc gamma receptor IIB; D017452:Receptors, IgG; D010047:Ovalbumin