What is the function of IL-1?

• A. Antiviral
• B. Pyrogen, acute inflammation
• C. Chemotactic for neutrophils
• D. Mediates septic shock

Answer: (B)

IL-1 is a proinflammatory cytokine that acts as an endogenous pyrogen and initiates acute inflammation. It is produced mainly by activated macrophages in response to pathogens and tissue damage. As a fever mediator, IL-1 signals the hypothalamus to raise the body's temperature by promoting prostaglandin E2 production, which shifts the set point upward. In terms of inflammation, IL-1 stimulates the endothelium to upregulate adhesion molecules, aiding leukocyte adhesion and extravasation, and it drives the production of other inflammatory mediators like IL-6, amplifying the acute inflammatory response. While IL-1 can contribute to septic shock at high levels, its defining function in this context is fever induction and initiation of acute inflammation, making the described option the best fit.