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Updated: Sep 26, 2026

An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions
08:40

An ELISA Based Binding and Competition Method to Rapidly Determine Ligand-receptor Interactions

Published on: March 14, 2016

IL-18 receptor beta-induced changes in the presentation of IL-18 binding sites affect ligand binding and signal

Chengbin Wu1, Paul Sakorafas, Renee Miller

  • 1Abbott Bioresearch Center, Worcester, MA 01605, USA. chengbin.wu@abbott.com

Journal of Immunology (Baltimore, Md. : 1950)
|May 22, 2003
PubMed

IL-18 is a pleiotropic proinflammatory cytokine that is involved in induction of inflammatory mediators, regulation of the cytotoxic activity of NK cells and T cells, and differentiation and activation of both Th1 and Th2 cells. IL-18 signals through its specific cell surface receptor IL-18R, which comprises two subunits: IL-18R alpha and IL-18R beta. IL-18R alpha alone has a weak affinity for IL-18 binding, while the IL-18R alpha/beta complex has a high affinity. By using several anti-IL-18 mAbs and IL-18 binding protein, we have examined whether these site-specific inhibitors could block the binding of IL-18 to IL-18R alpha and to the IL-18R alpha/beta complex. Here we show that IL-18 binding to IL-18R alpha was inhibited by a neutralizing mAb, 125-2H, while binding of IL-18 to the alpha/beta receptor complex was not. This suggests that IL-18R beta-induced conformational changes may occur in IL-18R alpha upon dimerization, leading to changes in the presentation of IL-18 binding sites. Epitope mapping of 125-2H using human-mouse IL-18 chimeras identified a region in IL-18 that was required for 125-2H recognition. This region, as examined by IL-18R binding and functional analysis, appeared to be critical for triggering signal transduction through the heterodimeric receptor.

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