<P> Clonal selection theory is a scientific theory in immunology that explains the functions of cells (lymphocytes) of the immune system in response to specific antigens invading the body . The concept was introduced by the Australian doctor Frank Macfarlane Burnet in 1957, in an attempt to explain the formation of a diversity of antibodies during initiation of the immune response . The theory has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens . </P> <P> The theory states that in a pre-existing group of lymphocytes (specifically B cells), a specific antigen only activates (i.e. selection) its counter-specific cell so that particular cell is induced to multiply (producing its clones) for antibody production . This activation occurs in secondary lymphoid organs such as the spleen and the lymph nodes . In short the theory is an explanation of the mechanism for the generation of diversity of antibody specificity . The first experimental evidence came in 1958, when Gustav Nossal and Joshua Lederberg showed that one B cell always produces only one antibody . The idea turned out to be the foundation of molecular immunology, especially in adaptive immunity . </P> <P> The clonal selection theory can be summarised with the following four tenets: </P>

Where does clonal selection of t cells happen