title: Endocytosis and recycling of immune complexes by follicular dendritic cells enhances B cell antigen binding and activation.
abstract: Stromal-derived follicular dendritic cells (FDCs) are a major reservoir for antigen that are essential for formation of germinal centers, the site where memory and effector B cells differentiate. A long-standing question is how FDCs retain antigen in its native form for extended periods and how they display it to specific B cells. Here we found that FDCs acquired complement-coated immune complexes (ICs) from noncognate B cells via complement receptors 1 and 2 (CD35 and CD21, respectively) and rapidly internalized them by an actin-dependent pathway. ICs were retained intact within a nondegradative cycling compartment and were displayed periodically on the cell surface where they were accessible to antigen-specific B cells. This would explain how antigens are protected from damage and retained over long periods of time, while remaining accessible for B cells.
authors.affiliation: The Program in Cellular and Molecular Medicine, Children's Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Balthasar A
authors.initials: BA
authors.lastname: Heesters
authors.forename: Priyadarshini
authors.initials: P
authors.lastname: Chatterjee
authors.forename: Young-A
authors.initials: YA
authors.lastname: Kim
authors.forename: Santiago F
authors.initials: SF
authors.lastname: Gonzalez
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kuligowski
authors.forename: Tomas
authors.initials: T
authors.lastname: Kirchhausen
authors.forename: Michael C
authors.initials: MC
authors.lastname: Carroll
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D017951:Antigen Presentation; D000936:Antigen-Antibody Complex / Q000276:immunology / Q000378:metabolism*; D000941:Antigens / Q000276:immunology / Q000378:metabolism*; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D020566:Dendritic Cells, Follicular / Q000276:immunology*; D004705:Endocytosis / Q000276:immunology; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D011485:Protein Binding; D017463:Receptors, Complement 3b / Q000378:metabolism; D017464:Receptors, Complement 3d / Q000378:metabolism
chemical_list: D000199:Actins; D000936:Antigen-Antibody Complex; D000941:Antigens; D017463:Receptors, Complement 3b; D017464:Receptors, Complement 3d