Characterization of Lipoprotein Particles Isolated by Monoclonal-anti-apo A-I Affinity hromatography

Abstract

We have isolated lipoprotein particle containingapolipoprotein A-I (apo A-I) directly from human plasma by anti-apo A-I monoclonal antibody conjugated affinity column (apo column A-I).
Monoclonal antibody against apo A-I was obtained from ascites of BALB/c mouse induced by injection of hybridoma producing anti-apo A-I antibody.
The lipoprotein particle containing apo A-I (apo A-I particle) was richer in apo A-I and triglyceride (TG) than HDL separated by ultracentrifugation. The mean diameter of apo A-I particle was slightly larger (137±28Å, Mean±S. D.) and more polydisperse in diameter than of HDL (133±22Å). The recovery of these particle protein from the same plasma through two different methods, ultracentrifugation and apo column A-I, was similar.
Unknown protein of molecular weight about 75, 000, which is not normaly seen in HDL, was detected in apo A-I particle on SDS-polyacryl-amide gel.
In the study of fat tolerance test, apolipoprotein and lipid composition of both apo A-I particle and HDL did not show any change during fat loading per os, eventhough TG rich lipoprotein (chylomicron and VLDL) was increased extremely in plasma. As chylomicron contains apo A-I, no appearance of chylomicron derived apolipoprotein (e. g. apo B₄₈) in apo A-I particle during fat loading suggested large particle like chylomicron may not be retained by this affinity column.