Which term describes the immune system’s ability to rapidly respond to a previously encountered pathogen due to immune memory?

• A. Primary immune response
• B. Active immunity
• C. Memory response
• D. Innate response

Answer: (C)

Memory response describes the immune system’s rapid recall of a pathogen it has seen before, because memory B and T cells persist after the first encounter. After initial exposure, these memory cells remain in the body and are ready to respond fast if the same pathogen appears again. Upon re-exposure, memory B cells quickly produce antibodies, and memory T cells coordinate a swift, targeted attack, yielding a quicker and stronger defense and often preventing illness or reducing its severity. This is different from the primary immune response, which happens on first exposure and is slower; active immunity refers to the immune system actively generating that response (such as after vaccination or infection) but doesn’t specifically name the rapid recall process itself; the innate response is non-specific and lacks this memory-driven speed.