Recombinant Cynomolgus Monkey IL-18 BPa His-tag Protein, CF

Cynomolgus Interleukin 18 binding protein (IL-18 BP) is a 20 kDa secreted glycoprotein, which functions as an IL-18 antagonist by binding to IL-18 and blocking its biological activity (1). IL-18 BP bears no amino acid sequence homology to the membrane-associated IL-18 and IL-1 receptor proteins. Human IL-18BP encodes for at least four isoforms by alternative splicing. The IL-18 BP isoform a and c each contains one immunoglobulin (Ig)-like C2-type domain while isoform b and d lack a complete Ig domain. The complete Ig domain has been shown to be essential to the binding and neutralizing properties of the binding proteins (2). Cynomolgus IL-18BPa shares 83% sequence identity with human and 62% with mouse IL-18BPa, respectively. Several poxviruses also encode proteins with sequence similarity to IL-18 BP. Viral IL-18 BPs have been shown to bind and inhibit IL-18 responses and may be involved in modulating host immune responses. The expression of IL-18 BP is markedly upregulated by IFN-gamma, suggesting that IL-18 activity is modulated by a negative feedback mechanism mediated by IL-18 BP (3).