Which of the following best characterizes clonal selection in the immune system?

• A. Random generation of antibodies without antigen exposure
• B. Destruction of all lymphocytes after antigen exposure
• C. Production of identical clones of all immune cells regardless of specificity
• D. Activation and proliferation of lymphocytes that specifically recognize an antigen

Answer: (D)

Verified step by step guidance

1. Understand that clonal selection is a fundamental concept in immunology describing how the immune system responds to specific antigens.
2. Recall that lymphocytes (B cells and T cells) each have unique receptors generated randomly before encountering any antigen.
3. Recognize that when an antigen enters the body, only those lymphocytes with receptors specific to that antigen are activated.
4. These activated lymphocytes then proliferate (divide) to produce a population (clone) of cells that all recognize the same antigen, enhancing the immune response.
5. Therefore, clonal selection is best characterized by the activation and proliferation of lymphocytes that specifically recognize an antigen, rather than random antibody generation or destruction of lymphocytes.