Why does the **secondary immune response** to a known antigen produce more antibodies, faster, than the primary response?
AAntigen is recognised faster by macrophages
BMemory B cells (and memory T cells) from primary exposure proliferate rapidly and differentiate into plasma cells (IgG dominant) within days
CAntibodies are pre-formed
DLymph nodes are larger
Answer & Solution
Correct answer: B. Memory B cells (and memory T cells) from primary exposure proliferate rapidly and differentiate into plasma cells (IgG dominant) within days
Primary response: takes 1-2 weeks; IgM dominant; modest titres. Memory cells persist after antigen clears. Secondary response: memory cells reactivate, proliferate, class-switch to IgG/IgA → fast (days), high antibody titres. Basis of vaccination booster shots.
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