Final answer:
Clonal selection is the process by which B cells and T cells are chosen and expanded in response to a specific antigen. B cells undergo clonal selection in the bone marrow, while T cells undergo clonal selection in the thymus. This ensures that only the cells with the appropriate antigen specificity are activated and multiplied.
Step-by-step explanation:
In the immune system, clonal selection is the process by which B cells and T cells are chosen and expanded in response to a specific antigen. This process ensures that only the cells with the appropriate antigen specificity are selected and undergo expansion.
For B cells, clonal selection occurs in the bone marrow. During maturation, a large number of B cell clones, each with a unique antigen receptor, are generated. When an antigen binds to a specific B cell receptor, that B cell is selected and undergoes further expansion to produce plasma cells that secrete antibodies with the same antigen specificity.
Similarly, for T cells, clonal selection happens in the thymus. T cells with specific receptors that can bind to antigens presented on self-MHC molecules are selected and expanded. This process ensures that only T cells capable of recognizing and responding to specific antigens are activated and multiplied.