title: Activation of B cells by antigens on follicular dendritic cells.
abstract: A need for antigen-processing and presentation to B cells is not widely appreciated. However, cross-linking of multiple B cell receptors (BCRs) by T-independent antigens delivers a potent signal that induces antibody responses. Such BCR cross-linking also occurs in germinal centers where follicular dendritic cells (FDCs) present multimerized antigens as periodically arranged antigen-antibody complexes (ICs). Unlike T cells that recognize antigens as peptide-MHC complexes, optimal B cell-responses are induced by multimerized FDC-ICs that simultaneously engage multiple BCRs. FDC-FcgammaRIIB mediates IC-periodicity and FDC-BAFF, FDC-IL-6 and FDC-C4bBP are co-stimulators. Remarkably, specific antibody responses can be induced by FDC-ICs in the absence of T cells, opening up the exciting possibility that people with T cell insufficiencies may be immunized with T-dependent vaccines via FDC-ICs.
authors.affiliation: Department of Microbiology and Immunology, Virginia Commonwealth University, PO Box 980678, Richmond, VA 23298-0678, USA.
authors.forename: Mohey Eldin M
authors.initials: ME
authors.lastname: El Shikh
authors.forename: Rania M
authors.initials: RM
authors.lastname: El Sayed
authors.forename: Selvakumar
authors.initials: S
authors.lastname: Sukumar
authors.forename: Andras K
authors.initials: AK
authors.lastname: Szakal
authors.forename: John G
authors.initials: JG
authors.lastname: Tew
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000936:Antigen-Antibody Complex / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology*; D020566:Dendritic Cells, Follicular / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D011947:Receptors, Antigen, B-Cell / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000936:Antigen-Antibody Complex; D011947:Receptors, Antigen, B-Cell