title: Functional anatomy of germinal centers.
abstract: This year we celebrate the first centennial of the discovery of germinal centers by Flemming in 1884. The present paper reviews and adds new data to the functional anatomy of a germinal center. Emphasizing its reactive nature, we first describe a germinal center reaction and then deal with its infrastructural aspects and constituent cell populations, both lymphoid and nonlymphoid. Elements involved in the de novo formation of a germinal center, like antigen, T cells, and the mysterious germinal-center-precursor cell, are discussed. Next, attention is paid to the requirements for lymphoid cells to migrate into germinal centers, and novel features of germinal-center-seeking cells are presented. Subsequently, we discuss kinetic aspects of the high proliferative activity in a germinal center; and finally a description of the functional capacities of germinal-center-derived cells, such as B memory cells and IgM-antibody-forming cell precursors, completes this picture of present-day knowledge of the germinal center, a structure which has yet to reveal its last secrets.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000917:Antibody Formation; D000941:Antigens / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology; D002454:Cell Differentiation; D003712:Dendrites / Q000648:ultrastructure; D007075:Immunoglobulin M / Q000276:immunology; D007136:Immunoglobulins / Q000378:metabolism; D007700:Kinetics; D008198:Lymph Nodes / Q000033:anatomy & histology* / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D008264:Macrophages / Q000166:cytology; D010641:Phenotype; D051381:Rats; D013499:Surface Properties; D013601:T-Lymphocytes / Q000166:cytology / Q000502:physiology; D009626:Terminology as Topic
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000941:Antigens; D007075:Immunoglobulin M; D007136:Immunoglobulins