Scios Nova Inc., Mountain View, California 94043.
The oxidation of low density lipoprotein (LDL) in the arterial wall is thought to contribute to human atherosclerotic lesion formation, in part by the high affinity uptake of oxidized LDL (OxLDL) by macrophages, resulting in foam cell formation. We have utilized cloning by expression to identify CD36 as a macrophage receptor for OxLDL. Transfection of a CD36 clone into 293 cells results in the specific and high affinity binding of OxLDL, followed by its internalization and degradation. An anti-CD36 antibody blocks 50% of the binding of OxLDL to platelets and to human macrophage-like THP cells. Furthermore, like mouse macrophages, 293 cells expressing CD36 recognize LDL which has been oxidized only 4 h, whereas more extensive oxidation of the LDL is required for recognition by the other known OxLDL receptors, the acetylated LDL (AcLDL) receptor and Fc gamma RII-B2. CD36 may play a role in scavenging LDL modified by oxidation and may mediate effects of OxLDL on monocytes and platelets in atherosclerotic lesions.