A secondary immune response to a given antigen is generally a weaker response than the primary response.

• A. True
• B. False
• C. Both
• D. Neither

Answer: (B)

A memory-based response is faster and stronger than the first exposure. After the initial encounter, memory B cells (and memory T cells) persist. When the same antigen is encountered again, these memory cells quickly react, proliferate, and differentiate into plasma cells that secrete large amounts of antibodies. The lag time before antibodies appear is shortened, and the overall antibody titer is higher compared with the primary response. The antibodies are typically of higher affinity due to affinity maturation, and class switching often yields more IgG (sometimes IgA) antibodies. This rapid, robust response is called an anamnestic response, and it explains why the secondary response is not weaker but stronger.