Intended use

This immunoassay kit allows for the in vitro quantitative determination of human Interleukin 18, IL-18 concentrations in cell culture supernates, serum, plasma and other biological fluids.

Introduction

Interleukin 18 (IL-18) is a 18 kDa novel cytokine which is identified as a costimulatory factor for production of interferon-γ (IFN- γ ) in response to toxic shock. It shares functional similarities with IL-12. IL-18 is synthesized as a precursor 24 kDa molecule without a signal peptide and must be cleaved to produce an active molecule. IL-1 ß converting enzyme (ICE, Caspase-1) cleaves pro-IL-18 at aspartic acid in the P1 position, producing the mature, bioactive peptide that is readily released from the cells. It has been reported that IL-18 is produced from Kupffer cells, activated macrophages, keratinocytes, intestinal epithelial cells, osteoblasts, adrenal cortex cells and murine diencephalon.

IL-18 acts on T helper 1-type T (Th1) cells and in combination with IL-12 strongly induces production of IFN- γ by these cells. Pleiotropic effects of IL-18 have also been reported, including enhancement production of IFN- γ and GM-CSF in peripheral blood mononuclear cells, production of T helper type 1 cytokines, IL-2, GM-CSF and IFN-γ in T cells, enhancement of Fas ligand expression by T helper type 1 cells.