Cellular Binding of Soluble CD14 Requires Lipopolysaccharide (LPS) and LPS-binding Protein

Lipopolysaccharide (LPS)-binding protein accelerates the binding of LPS to CD14

CD14 is a 55-kD protein found as a glycosylphosphatidylinositol (GPI)-anchored protein on the surface of monocytes, macrophages, and polymorphonuclear leukocytes, and as a soluble protein in the blood. Both forms of CD14 participate in the serum-dependent responses of cells to bacterial lipopolysaccharide (LPS). While CD14 has been described as a receptor for complexes of LPS with LPS-binding p...

Membrane-anchored forms of lipopolysaccharide (LPS)-binding protein do not mediate cellular responses to LPS independently of CD14.

Inflammatory responses of myeloid cells to LPS are mediated through CD14, a glycosylphosphatidylinositol-anchored receptor that binds LPS. Since CD14 does not traverse the plasma membrane and alternatively anchored forms of CD14 still enable LPS-induced cellular activation, the precise role of CD14 in mediating these responses remains unknown. To address this, we created a transmembrane and a g...

Chylomicrons Mediates LPS Detoxification by Lipopolysaccharide (LPS)-Binding Protein

Cutting edge: cationic antimicrobial peptides block the binding of lipopolysaccharide (LPS) to LPS binding protein.

We investigated the mechanism by which cationic antimicrobial peptides block the activation of macrophages by LPS. The initial step in LPS signaling is the transfer of LPS to CD14 by LPS binding protein (LBP). Because many cationic antimicrobial peptides bind LPS, we asked whether these peptides block the binding of LPS to LBP. Using an assay that measures the binding of LPS to immobilized LBP,...

Transfection of CD14 into 70Z/3 cells dramatically enhances the sensitivity to complexes of lipopolysaccharide (LPS) and LPS binding protein

Bacterial endotoxin (lipopolysaccharide [LPS]) causes fatal shock in humans and experimental animals. The shock is mediated by cytokines released by direct LPS stimulation of cells of monocytic origin (monocyte/macrophage [MO]). Recent studies have supported the concept that the plasma protein, LPS binding protein (LBP), plays an important role in controlling MO responses to LPS. Specifically, ...