Which part of the immune system is responsible for acquired immunity?

• A. Physical barriers
• B. Leukocytes
• C. Immunocytes
• D. Inflammatory mediators

Answer: (C)

Acquired immunity, also known as adaptive immunity, is primarily facilitated by immunocytes, which are specialized cells of the immune system. These cells include B cells and T cells, which play a critical role in recognizing specific pathogens, generating targeted responses, and developing immunological memory.

B cells are responsible for the production of antibodies, which are proteins that bind to specific antigens on pathogens, marking them for destruction. T cells, on the other hand, can directly kill infected cells or help regulate the immune response. This specificity and memory capability distinguish acquired immunity from innate immunity, which is more generalized and immediate.

While leukocytes, such as phagocytes and natural killer cells, play an essential role in both innate and acquired immunity, they are not exclusively responsible for the acquired immune response. Physical barriers, like skin and mucous membranes, provide the first line of defense against pathogens but do not involve specific immune recognition. Inflammatory mediators are involved in the inflammatory response, which is part of innate immunity, and help recruit immune cells to sites of infection but do not directly confer acquired immunity. Thus, immunocytes are the correct answer as they are integral to the processes that define acquired immune responses.