IL-1 RII/CD121b Fc Chimera Protein, Human

Interleukin-1 receptor type 2 (IL1R2), also referred to as CD121 antigen-like family member B (CDw121b) or the IL-1 type II receptor, is a member of the interleukin-1 receptor family. Two specific IL-1 binding receptors have been identified: IL1RI (also known as IL1RA) and IL1RII (also known as IL1RB).
IL1R2 is a non-signaling receptor that binds to IL1A, IL1B, and IL1RN, and it plays a role in reducing the activities of IL1B. It functions as a decoy receptor by competitively binding to IL1B, thereby preventing its interaction with IL1R1. After binding to IL1B, IL1R2 modulates cellular responses through a non-signaling association with IL1RAP.
Both membrane-bound and secreted forms of IL1R2 show a preference for binding to IL1B, with less affinity for IL1A and IL1RN. The secreted form of IL1R2 has a high affinity for secreted IL1RAP, and the formation of this complex is likely a primary mechanism for the neutralization of IL1B by soluble receptors. It is hypothesized that the type II receptor, in both its membrane-bound and soluble forms, acts as a decoy for IL-1, inhibiting its action by blocking the binding of IL-1 to the signaling type I receptor complex. The recombinant IL-1 soluble receptor type II is a potent antagonist of IL-1 activity.