Which leukocyte type is primarily involved in adaptive immunity?

• A. Lymphocytes
• B. Neutrophils
• C. Monocytes
• D. Eosinophils

Answer: (A)

Adaptive immunity relies on lymphocytes, which provide highly specific, memory-based responses. B cells produce antibodies that recognize and neutralize pathogens in the humoral branch, while T cells mediate targeted killing of infected cells and help regulate the immune response. These cells also form memory cells so future encounters with the same antigen trigger faster, stronger responses. Neutrophils are fast, non-specific first responders of innate immunity; monocytes become macrophages that phagocytose and present antigens (bridging innate and adaptive); eosinophils deal with parasites and participate in allergic responses. Because of their ability to recognize specific antigens and remember them, lymphocytes are the primary players in adaptive immunity.