Development of an ELISA to measure soluble CD163 in biological fluids

CD163 is a monocyte/macrophage restricted transmembrane glycoprotein and a member of the scavenger receptor cysteine-rich (SRCR) family of proteins. S RCR proteins are typically associated with the immune system. The regulatio n of CD163 by cytokines and glucocorticoids suggests that it plays a role i n inflammatory processes. While CD163 is expressed as a membrane-bound prot ein it has been shown to be actively shed from the surface of monocytes in a protease-dependent fashion when cells are stimulated with a phorbol ester . To better elucidate the function and biological importance of CD163, we h ave developed a solid-phase sandwich enzyme linked immunosorbant assay (ELI SA) for the detection of soluble CD163 in biological fluids. This assay has good repeatability both within and between runs (coefficients of Variation (CVs) of 3.2% and 7.1% or better, respectively). While detection of CD163 was inhibited by ethylenediamine tetraacetic acid (EDTA), CD163 immunoreact ivity was not altered by the addition of heparin or hemoglobin This report details the development of this novel assay for soluble CD163 and provides the first evidence of CD163 immunoreactivity in normal plasma and serum sam ples. (C) 2001 Elsevier Science B.V. all rights reserved.