Follicular dendritic cells

Abstract

Follicular dendritic cells (FDCs) are unique accessory immune cells that contribute to the regulation of humoral immunity. They are multitasker cells essential for the organization and maintenance of the lymphoid architecture, induction of germinal center reaction, production of B memory cells, and protection from autoimmune disorders. They perform their activities through both antigen‐driven and chemical signaling to B cells. FDCs play a crucial role in the physiological regulation of the immune response. Dis‐regulation of this immune response results when FDCs retain antigens for years. This provides a constant antigenic stimulation for B cells resulting in the development of immune disorders. Antigen trapped on FDCs is resistant to therapeutic intervention causing chronicity and recurrences. Beyond their physiological immunoregulatory functions, FDCs are involved in the pathogenesis of several immune‐related disorders including HIV/AIDS, prion diseases, chronic inflammatory, and autoimmune disorders. FDCs have also been recently implicated in rare neoplasms of lymphoid and hematopoietic tissues. Understanding FDC biology is essential for better control of humoral immunity and opens the gate for therapeutic management of FDC‐mediated immune disorders. Thus, the biology of FDCs has become a hot research area in the last couple of decades. In this review, we aim to provide a comprehensive overview of FDCs and their role in physiological and pathological conditions.

A Cytological Review of Follicular Dendritic Cell-Derived Tumors with Emphasis on Follicular Dendritic Cell Sarcoma and Unicentric Castleman Disease

“…FDCs are located in the primary and secondary follicles of the B-cell areas of the lymph nodes, spleen, and mucosal-associated lymphoid tissue. They constitute an exception among hematolymphoid cells since they do not derive from a common bone marrow hematopoietic precursor [ 1 , 2 , 3 ]. They are stromal in origin and develop from vascular mural cells within the lymph nodes [ 1 , 2 ].…”

“…They constitute an exception among hematolymphoid cells since they do not derive from a common bone marrow hematopoietic precursor [ 1 , 2 , 3 ]. They are stromal in origin and develop from vascular mural cells within the lymph nodes [ 1 , 2 ]. The same stromal cellular origin is shared with fibroblastic reticular cells (FRCs) that are also found in secondary lymphoid organs.…”

“…Conventional dendritic cells activate naive T cells by presenting a processed antigen via a major histocompatibility complex (MHC) molecules. In contrast, FDCs present an unprocessed antigen in the form of immunocomplexes [ 1 , 2 , 3 ]. FDCs are non-phagocytic and lack class II MHC molecules.…”

“…They locate in B follicles and are specialized in the capture of immunocomplexes that can remain for long periods in the cell surface and be presented to surrounding B-lymphocytes. This function is facilitated by the numerous cytoplasmic prolongations and interdigitations that form an intricate network connected through desmosomes [ 1 , 2 , 3 , 10 ]. In collaboration with macrophages, FDCs control the removal of apoptotic germinal center B cells.…”

“…Follicular dendritic cells (FDCs) are antigen-presenting cells located in the germinal centers of the lymph nodes [ 1 , 2 , 3 ]. Maximow originally described them as “reticular cells” in 1927 and noted the propensity of their cytoplasmic processes to form a network [ 4 ].…”