Which statement about immunological memory is accurate?

• A. It is a feature of the innate immune system
• B. Immunological memory develops only in the adaptive system
• C. It is not associated with any immune response
• D. It is a feature of the adaptive immune system

Answer: (D)

Immunological memory arises when the adaptive immune system is activated by a pathogen. B and T lymphocytes with receptors specific to that pathogen undergo clonal expansion and differentiate into effector cells and long-lasting memory cells. Memory B cells persist and can rapidly produce high-affinity antibodies upon re-exposure, while memory T cells respond quickly with targeted cellular activity. This accelerated and enhanced response upon a second encounter is the hallmark of immunological memory and is driven by the antigen-specific nature of the adaptive system. The innate immune system, by contrast, provides immediate, non-specific defense and does not generate lasting, specific memory to a particular pathogen in the same way. So, immunological memory is a feature of the adaptive immune system.