Follicular dendritic cells in health and disease

• Main Authors: Mohey Eldin M El Shikh, Costantino ePitzalis
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2012-09-01
• Series: Frontiers in Immunology
• Subjects: Antigen Presentation; Autoimmunity; Germinal Center; Lymphoma, B-Cell; Prion Diseases; Rheumatic Diseases
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fimmu.2012.00292/full

Follicular dendritic cells (FDCs) are unique immune cells that contribute to the regulation of humoral immune responses. These cells are located in the B cell follicles of secondary lymphoid tissues where they trap and retain antigens (Ags) in the form of highly immunogenic immune complexes (ICs) consisting of Ag plus specific antibody (Ab) and/or complement proteins. FDCs multimerise Ags and present them polyvalently to B cells in periodically arranged arrays that extensively crosslink the B cell receptors for Ag (BCRs). FDC-Fc-gamma-RIIB mediates IC periodicity, and FDC-Ag presentation combined with other soluble and membrane bound signals contributed by FDCs, like FDC-BAFF, -IL-6 and -C4bBP, are essential for the induction of the germinal centre (GC) reaction, the maintenance of serological memory, and the remarkable ability of FDC-Ags to induce specific Ab responses in the absence of cognate T cell help. On the other hand, FDCs play a negative role in several disease conditions including chronic inflammatory diseases, autoimmune diseases, HIV/AIDS, prion diseases and follicular lymphomas. Compared to other accessory immune cells, FDCs have received little attention, and their functions have not been fully elucidated. This review gives an overview of FDC structure, and recapitulates our current knowledge on the immunoregulatory functions of FDCs in health and disease. A better understanding of FDCs should permit better regulation of Ab responses to suit the therapeutic manipulation of regulated and dysregulated immune responses.