Low-density lipoprotein (LDL) is the carrier protein for cholesterol in the blood. LDL binds to its receptor on the capillary walls and thereby mediates the uptake and clearence of cholesterol from the circulation. In atherosclerotic lesions oxidatively modified LDL is found and oxidized LDL is specifically recognized and ingested by macrophages via scavenger receptor A and CD36. Oxidized LDL may be a marker of atherosclerosis but the precise changes in oxidized LDL are not well described. MDA-treated LDL appear to be different from LDL oxidized by other means. This antibody reacts with MDA-treated LDL but not with native LDL.