IL18BP, as known as interleukin-18-binding protein isoform, is a secreted glycoprotein. It belongs to the interleukin 1 receptor family. This protein functions as an IL18 antagonist by binding to IL18 and blocking its biological activity. Also, it is essential for IL18 meditated signal transduction. The expression of IL18BP is markedly upregulated by IFN-gamma, suggesting that IL18 activity is modulated by a negative feedback mechanism meditated by IL18BP. Recombinant human IL18BP, fused to hIgG-His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.