IL-1F9

The IL-1 family of cytokines is a set of structurally related molecules that are primary mediators of inflammation. This family now consists of 11 cytokines and 9 cell-surface receptors, the best characterized of which are IL-1α, IL-1β, IL-1 receptor antagonist (IL-1ra), and IL-18. Seven novel members were recently identified from DNA databases almost simultaneously by several different groups, and to reduce confusion, a systematic nomenclature was proposed. IL-1F6, IL-1F8, and IL-1F9 have all reported proinflammatory properties. IL-1F5 shares 52% amino acid similarity with IL-1ra and as such antagonizes IL-1F6 and IL-1F9 at the IL-1R3 (RAcP) –IL-1R6 (Rrp2) receptor complex. IL-1F7 acts as an attenuator of IL-18 activity and may act as an inhibitor of innate immune signaling.