[Follicular dendritic cells: phenotype, origin and functions].

Follicular dendritic cells (FDC) are only located in lymph node follicles and particularly developed in the light zones of the germinal centers. FDC differ on important points from the classical dendritic cells presenting antigens to T cells. They are long-lived and derived from local mesenchymal cells. Their complex cytoplasmic extensions, covered with dendrites, are intermingled in a network which surrounds germinal B and T cells. On their surface, receptors fix immune complexes without endocytosis and adhesion molecules ensure close contacts to the lymphoid cells. FDC influence the migration, activation, proliferation, survival and differentiation of B cells into memory cells and probably act also on the germinal center T cells.