iNOS, or inducible nitric oxide synthase, is an enzyme that produces nitric oxide (NO) in response to immune system signals. It plays a crucial role in the body's defense against pathogens by helping to regulate inflammation and kill bacteria. iNOS is primarily found in immune cells, such as macrophages, and is activated during infection or injury. The production of nitric oxide by iNOS can have both beneficial and harmful effects. While it helps fight infections, excessive NO can lead to tissue damage and contribute to inflammatory diseases. Understanding iNOS is important for developing treatments for conditions like sepsis and autoimmune disorders.