AF12198

AF12198 is a potent, selective and specific peptide antagonist for human type I interleukin-1 receptor (IL1-R1) (IC₅₀=8 nM) but not the human type II receptor (IC₅₀=6.7 µM) or the murine type I receptor (IC₅₀>200 µM). AF12198 inhibits IL-1-induced IL-8 production (IC₅₀=25 nM) and IL-1-induced intercellular adhesion molecule-1 (ICAM-1) expression (IC₅₀=9 nM) in vitro. AF12198 has anti-inflammatory activities and blocks responses to IL-1 in vivo^[1]. IC50 & Target:IC50: 8 nM (human IL1R1)^[1] In Vitro: AF12198 competes for binding of ¹²⁵I-IL-1α with an IC₅₀ of 8.0 nM, nearly equal to that of IL-1ra, IC₅₀ of 4.0 nM for the type I receptor^[1].
AF12198 (0-5 ng; 8 hours) inhibits IL-6 induction with an IC₅₀ of 15 μM whereas IL-1ra inhibits with an IC₅₀ of 2 nM in heparinized human primate blood. Meanwhile, With blood from cynomolgus monkeys, the IC₅₀ values are 17 μM for AF12198 and 30 nM for IL-1ra. Additionally, AF12198 or IL-1RA alone does not induce IL-6 in blood from either humans or cynomolgus monkeys^[1].
In Vivo: AF12198 (intravenous infusion; 16 mg/kg; 30 min before LPS intravenous injection) significantly attenuates the increase in lung MPO activity induced by LPS in acute lung inflammation and it reduces the lung microvascular leakage from rats inflamed with LPS at the 4 h (32.6%), 12 h (50.1%) and 24 h (65.3%) after LPS^[2].