Purification of Lipopolysaccharide-Binding Protein

Lipopolysaccharide (LPS)-binding protein (LBP) is a critical component of innate immunity, implicated in the initiation of host defences against Gram-negative bacteria. LBP alerts the host to the presence of minute amounts of LPS (1). LPS released from Gram-negative bacteria is present as aggregates, because of the amphiphilic structure of the molecule. LPS aggregates are transformed to monomers by the action of LBP, which has been described as a lipid-transfer molecule catalyzing movement of phospholipids including LPS (2–6). When LPS/LBP monomers are transferred to lipoproteins, LPS is inactivated; when LPS/LBP complexes are transferred to cells harboring CD14 at their surface, cells are activated. Thus, the relative contribution of these two pathways will determine the response of the host to LPS.