After an initial infection, what do memory cells do when the same pathogen reappears?

• A. Directly ingest pathogens.
• B. Prevent the immune system from responding.
• C. Produce antibodies quickly.
• D. Become memory plasma cells.

Answer: (C)

When a familiar pathogen reappears, the memory response kicks in with rapid antibody production. Memory B cells formed during the first infection persist in the body and quickly recognize the pathogen. They proliferate and differentiate into plasma cells that churn out large amounts of high-affinity antibodies. These antibodies neutralize the pathogen fast, often keeping it from causing illness or reducing its severity compared with the first encounter.

Direct ingestion of pathogens is done by phagocytes, not memory cells. Memory cells don’t prevent the immune system from responding; they enable a quicker response instead. And while memory B cells can become antibody-secreting plasma cells, the key effect upon re-exposure is the swift production of antibodies.