Effect of the proteolysis of low-density serum lipoproteins on their interaction with macrophages

125I-labelled human serum low density lipoproteins (LDL) were incubated with cultured mouse peritoneal macrophages at 37 degrees C, with the following study of cellular uptake and 125I-LDL degradation by measuring the content of TCA-soluble products of LDL hydrolysis in the cultural medium. It was shown that limited pepsin proteolysis of LDL (10%) led to a more effective LDL uptake and degradation by macrophages. The data suggest that enzyme-induced modification of LDL may increase their atherogenicity.