Which feature characterizes adaptive immunity?

Which feature characterizes adaptive immunity?

• A. It is specific to particular pathogens and has memory.
• B. It is solely a response to injury.
• C. It relies only on skin barriers.
• D. It does not involve immune cells.

Answer: (A)

Adaptive immunity is characterized by specificity to particular pathogens and the presence of memory. Specialized lymphocytes, B cells and T cells, recognize specific antigens on invaders and mount targeted responses. After the first exposure, these cells can expand and produce antibodies or activate other immune cells, and some of them become memory cells that persist for years. When the same pathogen appears again, these memory cells respond much more quickly and effectively, often preventing illness. This memory feature is what sets adaptive immunity apart from innate defenses, which respond in a non-specific way and don’t improve with repeated encounters. The other options describe barriers or general injury responses or immune elements that operate independently of learned specificity and memory, which belong to innate immunity rather than adaptive immunity.

Adaptive immunity is characterized by specificity to particular pathogens and the presence of memory. Specialized lymphocytes, B cells and T cells, recognize specific antigens on invaders and mount targeted responses. After the first exposure, these cells can expand and produce antibodies or activate other immune cells, and some of them become memory cells that persist for years. When the same pathogen appears again, these memory cells respond much more quickly and effectively, often preventing illness. This memory feature is what sets adaptive immunity apart from innate defenses, which respond in a non-specific way and don’t improve with repeated encounters. The other options describe barriers or general injury responses or immune elements that operate independently of learned specificity and memory, which belong to innate immunity rather than adaptive immunity.