Modulation of the expression of human LDL-Apo B-100 epitopes by lipids and apolipoproteins.
The purpose of the present study was to determine the immunochemical properties of apolipoprotein (apo) B-100 associated with low density lipoprotein (LDL) in relation to lipid and apolipoprotein composition. LDLs were isolated by sequential ultracentrifugation (1.019 < d < 1.050 g/mL) from two healthy volunteers and 21 dyslipidemic patients to obtain heterogeneous samples of LDL. Lipid (free cholesterol, cholesteryl esters, triglycerides, and phospholipids) and apolipoprotein contents (apo B, apo C-III, apo E) were determined in each LDL sample. Immunoreactivities of apo B were tested in solid-phase competitive-binding radioimmunoassays using seven monoclonal anti-LDL antibodies that reacted with defined epitopes of apo B-100. The relation between lipid and/or protein variables and the immunoreactivity of apo B was evaluated by successive use of Spearman's rank simple correlation, partial correlation, and canonical correlation analyses. The canonical correlation analysis showed that apo B-100 immunoreactivity on LDL is highly dependent on lipid and apolipoprotein composition simultaneously. The results confirmed the influence of surface and core lipids on the expression of the apo B-100 epitopes, independent of their location on the molecule. However, the lipid requirement of LDL strongly influences the expression of epitopes mapped in the LDL receptor-recognition domain. In contrast to apo E, apo C-III does not seem to influence the expression of the apo B-100 epitopes in the LDL range studied.(ABSTRACT TRUNCATED AT 250 WORDS)
Harduin
P
P
Serlia et Institut National de la Santé et de la Recherche Médicale (INSERM) U325, Institut Pasteur, Lille, France.
Tailleux
A
A
Fruchart
J C
JC
Fievet
C
C
D000911:Antibodies, Monoclonal; D053299:Apolipoprotein B-100; D001053:Apolipoproteins / Q000502:physiology*; D001055:Apolipoproteins B / Q000276:immunology*; D000939:Epitopes; D006402:Hematologic Diseases / Q000097:blood; D006801:Humans; D008055:Lipids / Q000097:blood / Q000502:physiology*; D008077:Lipoproteins, LDL / Q000276:immunology*; D011863:Radioimmunoassay; D012016:Reference Values; D014461:Ultracentrifugation
D000911:Antibodies, Monoclonal; D053299:Apolipoprotein B-100; D001053:Apolipoproteins; D001055:Apolipoproteins B; D000939:Epitopes; D008055:Lipids; D008077:Lipoproteins, LDL