THE CENTRAL ROLE OF FOLLICULAR DENDRITIC CELLS IN LYMPHOID-TISSUES

This chapter discusses the role of follicular dendritic cells in lymphoid tissues. Characteristic features of primary and secondary lymphoid follicles are follicular dendritic cells (FDCs) that are not found in any other human organ. FDCs were first described as a nonlymphoid population of embryonic nonphagocytic reticulum cells. Other names for FDCs have been used in the past, for example, dendritic reticulum cells (DRCs), follicular dendritic reticulum cells, antigen-retaining reticular cells, follicular antigen-binding dendritic cells, and dendritic macrophages. FDCs are considered as having a passive role in the function of the germinal center. It is characterized as nonphagocytic cells that capture and retain complexes of antigen, antibodies, and C3 on their cell surface. By expressing antigen–antibody complexes and a large number of cell–cell and cellmatrix molecules, FDCs were shown to regulate normal B cell function. There is growing evidence that FDCs could be important constituents of the malignant counterpart of the germinal center. In addition, FDCs were demonstrated to be the target cells in human immunodeficiency virus (HIV)-related lymphadenopathy. These data can be integrated into a concept of FDCs as the key component of the germinal center microenvironment. FDCs demonstrate a unique antigen pattern by co-expressing myeloid and B cell markers. © 1992, Academic Press Inc.