Modulation of Macrophage Tumoricidal Capability by Components of Normal Serum: A Central Role for Lipid

Abstract
The tumoricidal capabilities of macrophages can be reversibly inhibited by a lipoprotein of high molecular weight, and the inhibition appears to be reproduced by enrichment of macrophage plasma membranes with cholesterol. A second serum component of lower molecular weight enhances macrophage cytotoxicity. The presence of these components in normal serums suggests a physiological role for such factors in the regulation of macrophage function.