title: The bone marrow: the major source of serum immunoglobulins, but still a neglected site of antibody formation.
abstract: Immunoglobulin (Ig) secreting cells occur in all lymphoid tissues, including the bone marrow (BM). There are important differences between the various organs with respect to their number of Ig-secreting cells and the heavy chain isotype distribution of the secreted Igs. Furthermore, both distribution patterns depend on age. Early in life most Ig-secreting cells are localized in spleen and lymph nodes. In adults, however, the majority of all Ig-secreting cells of the individual are localized in the BM. Immunization can lead to the appearance of substantial numbers of antibody-forming cells in BM. The kinetics of the BM response are different from the response in the peripheral lymphoid tissues. Shortly after immunization most antibody-forming cells occur in the peripheral lymphoid tissues, but later on, especially during secondary type responses, most antibody-forming cells are localized in the BM. Apparently, antibody formation is regulated in such a way that peripheral lymphoid tissues respond rapidly, but only for a short period, whereas the BM response starts slowly, but takes care of a long-lasting massive production of antibodies to antigens which repeatedly challenge the organism.
mesh_terms: D000367:Age Factors; D000818:Animals; D000917:Antibody Formation; D000921:Antibody-Producing Cells / Q000378:metabolism; D001853:Bone Marrow / Q000276:immunology*; D006462:Hemolytic Plaque Technique; D006801:Humans; D007114:Immunization; D007136:Immunoglobulins / Q000096:biosynthesis*; D051379:Mice; D008815:Mice, Inbred Strains; D011817:Rabbits; D013997:Time Factors
chemical_list: D007136:Immunoglobulins