Development
After leaving the bone marrow, the B cell acts as an antigen presenting cell (APC) and internalizes offending antigens. That antigen is taken up by the B cell through receptor-mediated endocytosis and processed. Pieces of the pathogen (which are now known as antigenic peptides) are loaded onto MHC II molecules, and presented on its extracellular surface to CD4+ T cells (sometimes called T helper cells). These T cells bind to the MHC II/antigen molecule and cause activation of the B cell. Upon stimulation by a T cell, which usually occurs in germinal centers of secondary lymphoid organs like the spleen and lymph nodes, the activated B cell begins to differentiate into more specialized cells. Germinal center B cells may differentiate into memory B cells or plasma cells. The mechanism by which a B cell becomes one or the other of these three is a process known as affinity maturation. Most of these B cells will become plasmablasts, and eventually plasma cells, and begin producing large volumes of antibodies.
Read more about this topic: Plasma Cell
Famous quotes containing the word development:
“The man, or the boy, in his development is psychologically deterred from incorporating serving characteristics by an easily observable fact: there are already people around who are clearly meant to serve and they are girls and women. To perform the activities these people are doing is to risk being, and being thought of, and thinking of oneself, as a woman. This has been made a terrifying prospect and has been made to constitute a major threat to masculine identity.”
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—Benito Mussolini (1883–1945)
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—L. P. Wandersman (20th century)