What role do memory cells play in a secondary immune response?

• A. They enable a faster and stronger response
• B. They slow down the immune response
• C. They are destroyed after the primary response
• D. They have no effect on secondary responses

Answer: (A)

Memory cells provide the rapid, robust defense seen when the same pathogen is encountered again. After the first exposure, some B cells become memory B cells that persist for years. When the same antigen appears, these memory cells quickly recognize it and proliferate, differentiating into antibody-secreting plasma cells that produce large amounts of antibodies rapidly. Because these memory-derived responses often involve higher-affinity antibodies and faster antibody production, the secondary response is both quicker and stronger, often preventing illness or reducing its severity. Memory T cells also contribute by responding quickly to infected cells and helping coordinate the immune attack. This is why memory cells are central to why re-infections are typically fought off more efficiently.