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B Lymphocyte Function
difference is that the reaction of cytotoxic T cells is specific and directed at an infected cell that is recognized by the T cell receptor.
Sometimes, in the presence of superantigens, the T cells get too activated. This can happen with certain enterotoxins, exotoxins, and viruses. There is an excessive release of cytokines and overactivity of the T cells. The release of cytokines to such a degree is called a cytokine storm. It can lead to shock and death from multiple organ failure.
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B LYMPHOCYTE FUNCTION
B cells participate mainly in the humoral immune cell. As mentioned, they are matured in the bone marrow, where positive and negative selection occurs as it does with T cells. Those B cells that survive the selection process are called naïve B cells. B cells have B cell receptors, which are basically IgM and IgG antibodies bound to the B cell membrane. There is genetic rearrangement in order to have the diversity of B cell receptors necessary for immunity. These receptors do not need to have MHC reactivity in order to respond to an antigen. They can react to free antigens or antigens attached to membranes.
Some B cells need T cells to react. The antigens they react to are called T-dependent antigens. These are mainly proteins. Nonprotein antigens, like carbohydrates and lipopolysaccharides, are T-independent antigens because they don’t need antigen processing and T cell activity. An activated B cell that can proliferate into daughter cells is called a plasma cell. Plasma cells can make many different antibodies.
B cells can differentiate into memory B cells, which will last a long time. The helper 2 T cells have the ability to trigger the B cell to switch classes and make different types of antibodies than the initial IgM antibodies made by these cells. The constant region changes in these cases but not the variable region so the antigen-antibody relationship will be the same.
There will be a lag time or latent period of about 10 days, where no antibody to an organism will be detected. This happens during the primary response to a new infecting organism. IgM levels rise first and then other antibody types. After that, the IgG antibody levels rise, peaking at three weeks after the initial infection. Memory cells that
