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Follicular dendritic cells (FDCs) are cells of the immune system found in primary and secondary lymph follicles of the B cell areas of the lymphoid tissue. These cells were first described in 1965 and, although they have a very dendritic morphology, are not dendritic cells (DCs). Unlike DCs, FDCs are not derived from the bone-marrow hematopoetic stem cell, but are of mesenchymal origin. == Location and molecular markers == Follicular DCs are a non-migratory population found in primary and secondary follicles of the B cell areas of lymph nodes, spleen, and mucosa-associated lymphoid tissue (MALT). They form a stable network due to intercellular connections between FDCs processes and intimate interaction with follicular B cells. Follicular DCs network typically forms the center of the follicle and does not extend from the follicle to the interfollicular regions or T- cell zone. Supposedly, this separation from the sites of earliest antigen processing and capture provide a protected environment in which opsonized antigens can be displayed for a long time without being proteolyzed or removed by phagocytic cells. Follicular DCs have high expression of complement receptors CR1 and CR2 (CD 35 and CD 21 respectively) and Fc-receptor FcγRIIb (CD32). Further FDCs specific molecular markers are FDC-M1, FDC-M2 and C4. Unlike other DCs and macrophages, FDCs lack MHC class II antigen molecules and express few pattern-recognition receptors, so they have little ability to capture non-opsonized antigens. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「follicular dendritic cells」の詳細全文を読む スポンサード リンク
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