CD14 is a surface protein preferentially expressed on monocytes/macrophages. It binds lipopolysaccharide binding protein and recently has been shown to bind apoptotic cells.
CD14 is a single-copy gene encoding 2 protein forms: a 50- to 55-kD glycosylphosphatidylinositol-anchored membrane protein (mCD14) and a monocyte or liver-derived soluble serum protein (sCD14) that lacks the anchor. Both molecules are critical for lipopolysaccharide (LPS)-dependent signal transduction, and sCD14 confers LPS sensitivity to cells lacking mCD14. Increased sCD14 levels are associated with inflammatory infectious diseases and high mortality in gram-negative shock. |