Interleukin-1 receptor type 2 (IL1R2,also known as CD121b) is a cytokine receptor that belongs to the interleukin 1 receptor family. It exists in both a membrane bound and soluble form. IL1R2 binds interleukin alpha (IL1A),interleukin beta (IL1B),and interleukin 1 receptor,type I(IL1R1/IL1RA),and acts as a decoy receptor that inhibits the activity of its ligands. IL1R2 serves as a negative regulator of IL-1 signaling,thereby suppressing inflammatory response.