SERUM AMYLOID-P COMPONENT ASSOCIATES WITH HIGH-DENSITY-LIPOPROTEIN ASWELL AS VERY-LOW-DENSITY LIPOPROTEIN BUT NOT WITH LOW-DENSITY-LIPOPROTEIN

Serum amyloid P component (SAP) is a glycoprotein in human plasma. We previously showed that SAP is specifically localized in human atherosc lerotic lesions, suggesting that SAP may play a role in atherogenesis. In this study, the interactions between human SAP and high density li poprotein (HDL), low density lipoprotein (LDL) and very low density li poprotein (VLDL) were investigated by using a solid phase plate assay. Biotinylated SAP bound to immobilized HDL and VLDL in a calcium-depen dent, saturable manner. The SAP-HDL and SAP-VLDL bindings reached satu ration at 4 nM and 16 nM of SAP, respectively. The bindings were inhib ited by native SAP in a dose-dependent manner. No binding between SAP and LDL was found in the presence of calcium or EDTA, which indicates the specificity of SAP-lipoproteins interactions. These results sugges t that the function of SAP is related to its capability to interact wi th lipoproteins and this may have important implications in atheroscle rosis and in amyloidosis. (C) 1998 Academic Press.