Clonal Selection

The clonal selection theory (CST) is the theory used to explain the basic response of the adaptive immune system to an antigenic stimulus. It establishes the idea that only those cells capable of recognizing an antigenic stimulus will proliferate, thus being selected against those that do not. Clonal selection operates on both T-cells and B-cells. When antibodies on a B-cell bind with an antigen, the B-cell becomes activated and begins to proliferate. New B-cell clones are produced that are an exact copy of the parent B-cell, but then they undergo somatic hypermutation and produce antibodies that are specific to the invading antigen. The B-cells, in addition to proliferating or differentiating into plasma cells, can differentiate into long-lived B memory cells. Plasma cells produce large amounts of antibody which will attach themselves to the antigen and act as a type of tag for T-cells to pick up on and remove from the system. This whole process is known as affinity maturation. This...