[Characterization of macrophage cell (THP-1) surface apoE and it's role in metabolism of cell lipids]

To study the characterization of THP-1 cell surface apoE in order to learn the further role of macrophage in development of atherosclerosis.

Using monoclonal antibodies (7C9,3H1) against apoE to analyze the effects of AcLDL, heparin, chondroitinase, and Liposyn II on the apoE of THP-1 cell surface.

Cholesterol (AcLDL) loaded cell demonstrated reduced binding of 125I-7C9 to the cell surface by 19% at 4 degrees C, but if the THP-1 cell incubated at 37 degrees C for 2 hours after the removal of AcLDL there was a increase (25%) in 7C9 bound to loaded cells when compared to the 4 degrees C controls; prior loading with AcLDL also increased the secretion of apoE to the extracellular medium in a time-dependent manner; heparinase or chondroitinase ABC did not reduce the surface apoE associated with unloaded cells; the apoE on the surface of loaded macrophage was only marginally affected (9.3%) by incubation with heparinase but was efficiently reduced (50%) by incubation with chondroitinase ABC; Liposyn II dramatically increased the binding of apoA1 to the cell surface (1.5-1.8 fold), the Liposyn II mediated increased binding of apoA1 was antagonized by pre-incubation of THP-1 cells with 3H1 indicating that it was an apoE-dependent process.

Cell surface apoE of THP-1 macrophage relates to the process of cholesterol loading of macrophage cells and lipid mediated binding of apoA1 to the cell surface. It may affect the process of atherosclerosis development.