ABSTRACT
The concept that plasma lipoproteins can regulate cellular activation and proliferation is well established. Plasma lipoproteins and the cholesterol that they carry may be the critical “link” between dietary fat and immune cell function. Low-density lipoprotein inhibitor contains cholesterol. It has been suggested that the suppression of lymphocyte function might result from either interruption of cellular cholesterol biosynthesis or alteration of membrane integrity by cholesterol or its oxygenated derivatives. A biologically active moiety of the immunosuppressive lipoprotein, low-density lipoprotein inhibitor, that possesses regulatory activity characteristic of the native lipoprotein, has been identified as apolipoprotein E. Apoprotein E is also one of the major proteins synthesized and secreted by macrophages. The immune system is composed of a variety of cells and soluble factors, all of which play an important role in the maintenance and the proper functioning of the immune system. The effects of lipoproteins on immune cell function in vivo are exceedingly complex.
