What is clonal selection theory?

What is clonal selection theory?

• A. Antigen cross-reactivity and clonal expansion.
• B. Antigen specificity and clonal differentiation.
• C. Random mutation drives affinity maturation.
• D. MHC restriction governs selection.

Answer: (B)

Clonal selection theory is about how the adaptive immune system generates a targeted response by selecting the specific lymphocytes that carry receptors matching an invading antigen. Lymphocytes have diverse, receptor-bearing surfaces created by gene rearrangement, so there’s a wide repertoire. When an antigen enters, only those lymphocytes with receptors complementary to that antigen are activated. These antigen-specific cells then proliferate (clonal expansion) and differentiate into effector cells to fight the threat and memory cells to provide quicker, stronger responses if the same antigen is encountered again. This framework explains why responses are tailored to each invader rather than being a uniform reaction. While other concepts describe refinement of receptors or different modes of recognition (such as somatic mutations shaping affinity after activation, or MHC-restricted T cell recognition), the essential idea here is antigen-specific selection leading to clonal expansion and differentiation.

Clonal selection theory is about how the adaptive immune system generates a targeted response by selecting the specific lymphocytes that carry receptors matching an invading antigen. Lymphocytes have diverse, receptor-bearing surfaces created by gene rearrangement, so there’s a wide repertoire. When an antigen enters, only those lymphocytes with receptors complementary to that antigen are activated. These antigen-specific cells then proliferate (clonal expansion) and differentiate into effector cells to fight the threat and memory cells to provide quicker, stronger responses if the same antigen is encountered again. This framework explains why responses are tailored to each invader rather than being a uniform reaction. While other concepts describe refinement of receptors or different modes of recognition (such as somatic mutations shaping affinity after activation, or MHC-restricted T cell recognition), the essential idea here is antigen-specific selection leading to clonal expansion and differentiation.