Studies on the proteins involved in the interaction of high-density lipoprotein with isolated human small intestine epithelial cells.

Abstract Treatment of 125 I-labelled high-density lipoprotein ([ 125 I]HDL 3 ) with monospecific polyclonal antibodies against apolipoproteins A-I and A-II resulted in a dose-dependent inhibition of the [ 125 I]HDL 3 binding to isolated human small intestine epithelial cells by 25%, and 50%, respectively. Both antibodies also inhibited intracellular degradation of [ 125 I]HDL 3 by 80%. Treatment of enterocytes with polyclonal antibody against apolipoprotein A-I binding protein, a putative HDL receptor, inhibited both binding and degradation of [ 125 I]HDL 3 by these cells by 50%. Antibodies to apolipoprotein A-I, A-II and apo A-I-binding protein also inhibited [ 125 I]HDL 3 binding to cholesterol-loaded cells.