Which statement best captures clonal selection theory?

Which statement best captures clonal selection theory?

• A. All B cells are activated regardless of antigen specificity.
• B. Clonal selection requires presentation of antigen by MHC to B cells.
• C. Antigen specificity selects and expands the matching B and T cell clones.
• D. Clonal selection does not involve memory cell formation.

Answer: (C)

Clonal selection theory is about how the immune system chooses which lymphocytes to activate. Each lymphocyte carries a unique antigen receptor, and when an antigen is encountered, only the clones bearing receptors that fit that antigen are stimulated to proliferate. This selective expansion produces many identical effector cells and memory cells specific for that antigen. That’s why the best statement is that antigen specificity selects and expands the matching B and T cell clones. Other ideas don’t fit because not all B cells respond to every antigen, B cell activation isn’t solely about MHC presentation to B cells, and memory formation is a natural outcome of clonal expansion.

Clonal selection theory is about how the immune system chooses which lymphocytes to activate. Each lymphocyte carries a unique antigen receptor, and when an antigen is encountered, only the clones bearing receptors that fit that antigen are stimulated to proliferate. This selective expansion produces many identical effector cells and memory cells specific for that antigen. That’s why the best statement is that antigen specificity selects and expands the matching B and T cell clones. Other ideas don’t fit because not all B cells respond to every antigen, B cell activation isn’t solely about MHC presentation to B cells, and memory formation is a natural outcome of clonal expansion.