The Interleukin-1 Receptor (IL-1R) is a protein found on the surface of various immune cells. It plays a crucial role in the body's immune response by binding to the cytokines Interleukin-1α and Interleukin-1β. This interaction triggers a signaling cascade that activates immune responses, including inflammation, which helps the body fight infections and heal injuries. There are two main types of IL-1 receptors: IL-1R1, which is involved in signaling, and IL-1R2, which acts as a decoy receptor, preventing IL-1 from activating immune responses. Dysregulation of IL-1R signaling can contribute to various inflammatory diseases, making it a target for therapeutic interventions.