What are cytokines?

• A. Enzymes that digest pathogens
• B. Hormones produced by the adrenal cortex
• C. Molecules released when infection is detected to help fight infection
• D. White blood cells that engulf bacteria

Answer: (C)

Cytokines are signaling proteins released by immune cells in response to infection or injury. They act as chemical messengers that coordinate the body's defense, telling other immune cells to activate, migrate to the infection site, and boost processes like inflammation, phagocytosis, and fever. This makes them the molecules released when infection is detected to help fight infection. They’re not enzymes that digest pathogens, not adrenal cortex hormones, and not white blood cells themselves; instead, they guide and amplify the immune response.