title: The Role of Dendritic Cells in S. pneumoniae Transport to Follicular Dendritic Cells.
abstract: Affinity-mature B cells require cognate antigen, retained by follicular dendritic cells (FDCs), for clonal selection within germinal centers. Studies on how FDCs in lymphoid tissues acquire antigen have relied primarily on model protein antigens. To examine delivery of intact bacteria to FDCs, we used inactivated Streptococcus pneumonia (SP). We found that both medullary macrophages and a subset of SIGN-R1-positive dendritic cells (DCs) in the lymph node capture SP from the draining afferent lymphatics. The presence of DCs is required for initial complement activation, opsonization of the bacteria, and efficient transport of SP to FDCs. Moreover, we observed a major role for transport of bacteria to FDCs by naive B cells via a CD21-dependent pathway. We propose a mechanism by which efficient transport of SP to FDCs is dependent on DCs for initial binding and activation of complement and either direct transport to FDCs or transfer to naive B cells.
authors.affiliation: Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: b.a.heesters@amc.nl.
authors.forename: Balthasar A
authors.initials: BA
authors.lastname: Heesters
authors.affiliation: Program in Cellular and Molecular Medicine, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: michael.carroll@childrens.harvard.edu.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Carroll
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D015815:Cell Adhesion Molecules / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D020566:Dendritic Cells, Follicular / Q000276:immunology*; D018858:Germinal Center / Q000276:immunology; D037181:Lectins, C-Type / Q000276:immunology; D008198:Lymph Nodes / Q000276:immunology / Q000382:microbiology; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D011956:Receptors, Cell Surface / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000472:pathogenicity*; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
chemical_list: D015815:Cell Adhesion Molecules; D037181:Lectins, C-Type; D011956:Receptors, Cell Surface; D000099215:DC-Specific ICAM-3 Grabbing Nonintegrin
keywords: B cells; SIGN-R1; Streptococcus pneumoniae; antigen transport; complement; dendritic cells; follicular dendritic cells