The result is the formation of a population of identical cells called Clones, which can recognize the same specific antigen as the original lymphocyte. Swollen tonsils or lymph nodes are usually full of clones. Clones can be either effector cells or memory cells. 1000s of effector cells of a lymphocyte clone carry out immune responses that result in the destruction or inactivation of a specific antigen. Most effector cells die after the immune response. Memory cells do not actively participate in the initial immune response. However, if the same antigen enters the body in the future, 1000s of memory cells of a lymphocyte clone are available to react swiftly. The memory cells proliferate and differentiate into more effector cells and memory cells. Memory cells do not often die after an immune response. They often live for decades.
Cell-Mediated Immunity
Antigen invades a cell, stimulating the body cell to present the antigen fragment on a MHC I molecule. A T helper cell recognizes and correctly fits with the MH I complex. This stimulates clonal selection of T helper, T cytotoxic and T memory cells. The T cytotoxic cells kill the infected cell releasing the microbes. Phagocytes clean up the debris.
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