B cells are cells that develop from stem cells in the bone marrow and the liver of fetuses. They are transported to the lymph nodes and spleen where they use antigen receptors, also known as antigen-binding sites, on the cell's surface to seek out antigens.

Once an antigen is detected, the B cell with T cells activates a special group of lymphocytes that produces antibodies used in the antibody-mediated immunity response. T cells do not make antibodies. When B cells come in contact with extracellular antigens, the B cell transforms into plasma cells, that produce antibodies at about 2,000 antibodies per second to combat that antigen.

Memory cells are also produced when a B cell is stimulated by an antigen. A memory cell provides the organism with long-term immunity to the antigen.

B cells react to one kind of antigen that is referred to as its complementary antigen and are able to identify that antigen because antigen receptors bind to one specific antigen. Here's how it works: Once the antigen binds to the antigen receptor, the B cell replicates into a clonal selection. A clonal selection is a large cluster of clone cells.

An antibody attaches to an antigen at an antigen-binding site to form an antigen-antibody complex. This complex is very specific. However, when there are large quantities of antigens, the antigens attach to antibodies where they do not exactly fit. This makes for less-than-perfect matches for the antigen-antibody complex. These antibodies are said to have less affinity to the antigen.

B cells under go apoptosis if the B cell does not come in contact with an antigen. Apoptosis is a programmed death of the B cell that causes phagocytes to remove the cell from the organism.

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