Modified (desialylated) low-density lipoprotein measured in serum by lectin-sorbent assay

1995 ◽  
Vol 41 (7) ◽  
pp. 1018-1021 ◽  
Author(s):  
V V Tertov ◽  
I A Sobenin ◽  
A N Orekhov
Keyword(s):  
Ricinus Communis ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Diagnostic Value ◽  
Cellular Level ◽  
Chromatographic Technique ◽  
Low Density ◽  
Sialic Acid Content ◽  
Apo B

Abstract Modified low-density lipoprotein (LDL) with a low sialic acid content was found in the blood of patients with coronary atherosclerosis. This desialylated lipoprotein causes lipid accumulation in arterial smooth-muscle cells and stimulates cell proliferation and production of the extracellular matrix, i.e., induces all atherogenic manifestations at the cellular level. We have developed a lectin-sorbent assay for the determination of desialylated LDL in sera. The assay is based on the binding of desialylated LDL by immobilized Ricinus communis agglutinin with subsequent measurement of lipoprotein through use of anti-apolipoprotein (apo) B antibody. The assay is sensitive to desialylated apo B concentrations as low as 5 micrograms/L. The intraassay and interassay CVs were 4.8% and 11.3%, respectively. Comparison between the lectin-sorbent assay and a lectin chromatographic technique showed a good correlation. This determination of modified desialylated LDL in human serum with high accuracy and reproducibility may help establish the diagnostic value of this lipoprotein as a risk factor of atherosclerosis.

scholarly journals Low Density Lipoprotein-Containing Circulating Immune Complexes: Role in Atherosclerosis and Diagnostic Value

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Igor A. Sobenin ◽  
Jukka T. Salonen ◽  
Andrey V. Zhelankin ◽  
Alexandra A. Melnichenko ◽  
Jari Kaikkonen ◽  
...  
Keyword(s):  
Immune Complexes ◽  
Neutral Lipids ◽  
Low Density Lipoprotein ◽  
Atherosclerotic Lesion ◽  
Density Lipoprotein ◽  
Diagnostic Value ◽  
Circulating Immune Complexes ◽  
Low Density ◽  
Sialic Acid Content

It has been suggested that low density lipoprotein-containing circulating immune complexes (LDL-CIC) play a role in atherogenesis and are involved in the formation of early atherosclerotic lesion. These complexes, as well as anti-LDL autoantibodies, have been found in the blood and in the atherosclerotic lesions of patients with different cardiovascular diseases, as well as in the blood of animals with experimental atherosclerosis. It can be suggested that the presence of anti-LDL antibodies in the blood is a result of immune response induced by lipoprotein modification. LDL-CIC differs from native LDL in many aspects. It has much lower sialic acid content, smaller diameter, and higher density and is more electronegative than native LDL. Fraction of LDL-CICs is fundamental to the serum atherogenicity manifested at the cellular level. LDL-CIC, unlike native LDL, is able to induce intracellular accumulation of neutral lipids, especially esterified cholesterol, in cells cultured from uninvolved human aortic intima and in macrophage cultures. After removal of LDL-CIC, the CHD patient’s sera lose their atherogenic properties. Titer of LDL-CIC in blood serum significantly correlates with progression of atherosclerosis in humanin vivoand has the highest diagnostic value among other measured serum lipid parameters. Elevated CIC-cholesterol might well be a possible risk factor of coronary atherosclerosis.

Low-density-lipoprotein apoprotein B in plasma as measured by radial immunodiffusion and rocket immunoelectrophoresis.

1981 ◽  
Vol 27 (11) ◽  
pp. 1829-1833 ◽  
Author(s):  
L Havekes ◽  
J Hemmink ◽  
E de Wit
Keyword(s):  
Plasma Proteins ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Radial Immunodiffusion ◽  
Agarose Gel ◽  
Low Density ◽  
Plasma Samples ◽  
Apo B ◽  
Apoprotein B

Abstract Radial immunodiffusion (RID) and rocket immunoelectrophoresis (RIE) are compared with respect to determination of LDL-bound apo B in plasma. Isolated VLDL could not enter a 15 g/L agarose gel when either technique was used. However, in the presence of plasma proteins, migration of VLDL into agarose was enhanced. Only when plasma samples were kept frozen before the assay was plasma VLDL unable to enter the agarose gel when RID was used. With RIE the contribution of plasma VLDL to the apo B determination under these conditions was not always negligible. Besides enhancing the entry of VLDL into the agarose, the presence of proteins also influences apo B immunoreactivity of LDL and VLDL. For measuring LDL-bound apo B directly in unfractionated plasma we recommend: (a) RID in 15 g/L agarose gel; (b) freezing the plasma samples before assay; (c) diluting the plasma samples in saline supplemented with protein in the same concentration as is present in plasma (70 g/L); and (d) using plasma as the assay standard.

scholarly journals Development of Capture Assays for Different Modifications of Human Low-Density Lipoprotein

2005 ◽  
Vol 12 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Gabriel Virella ◽  
M. Brooks Derrick ◽  
Virginia Pate ◽  
Charlyne Chassereau ◽  
Suzanne R. Thorpe ◽  
...  
Keyword(s):  
Oxidized Ldl ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Gas Chromatography Mass Spectrometry ◽  
Low Density ◽  
Modified Ldl ◽  
Capture Assay ◽  
Carboxymethyl Lysine

ABSTRACT Antibodies to malondialdehyde (MDA)-modified low-density lipoprotein (LDL), copper-oxidized LDL (oxLDL), N ε(carboxymethyl) lysine (CML)-modified LDL, and advanced glycosylation end product (AGE)-modified LDL were obtained by immunization of rabbits with in vitro-modified human LDL preparations. After absorption of apolipoprotein B (ApoB) antibodies, we obtained antibodies specific for each modified lipoprotein with unique patterns of reactivity. MDA-LDL antibodies reacted strongly with MDA-LDL and also with oxLDL. CML-LDL antibodies reacted strongly with CML-LDL and also AGE-LDL. oxLDL antibodies reacted with oxLDL but not with MDA-LDL, and AGE-LDL antibodies reacted with AGE-LDL but not with CML-LDL. Capture assays were set with each antiserum, and we tested their ability to capture ApoB-containing lipoproteins isolated from precipitated immune complexes (IC) and from the supernatants remaining after IC precipitation (free lipoproteins). All antibodies captured lipoproteins contained in IC more effectively than free lipoproteins. Analysis of lipoproteins in IC by gas chromatography-mass spectrometry showed that they contained MDA-LDL and CML-LDL in significantly higher concentrations than free lipoproteins. A significant correlation (r = 0.706, P < 0.019) was obtained between the MDA concentrations determined by chemical analysis and by the capture assay of lipoproteins present in IC. In conclusion, we have developed capture assays for different LDL modifications in human ApoB/E lipoprotein-rich fractions isolated from precipitated IC. This approach obviates the interference of IC in previously reported modified LDL assays and allows determination of the degree of modification of LDL with greater accuracy.

scholarly journals Ligand selectivity of 105 kDa and 130 kDa lipoprotein-binding proteins in vascular-smooth-muscle-cell membranes is unique

1996 ◽  
Vol 317 (1) ◽  
pp. 297-304 ◽  
Author(s):  
Valery N. BOCHKOV ◽  
Vsevolod A. TKACHUK ◽  
Maria P. PHILIPPOVA ◽  
Dimitri V. STAMBOLSKY ◽  
Fritz R. BÜHLER ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Binding Proteins ◽  
Low Density Lipoprotein ◽  
Ldl Receptor ◽  
Density Lipoprotein ◽  
Low Density ◽  
Dextran Sulphate ◽  
Apo B ◽  
Ligand Selectivity ◽  
Lipoprotein Binding

Using ligand blotting techniques, with low-density lipoprotein (LDL) as ligand, we have previously described the existence of atypical lipoprotein-binding proteins (105 kDa and 130 kDa) in membranes from human aortic medial tissue. The present study demonstrates that these proteins are also present in membranes from cultured human (aortic and mesenteric) and rat (aortic) vascular smooth-muscle cells (VSMCs). To assess the relationship of 105 and 130 kDa lipoprotein-binding proteins to known lipoprotein receptors, ligand binding specificity was studied. We tested effects of substances known to antagonize ligand binding to either the LDL [apolipoprotein B,E (apo B,E)] receptor (dextran sulphate, heparin, pentosan polysulphate, protamine, spermine, histone), the scavenger receptor (dextran sulphate, fucoidin), the very-low-density-lipoprotein (VLDL) receptor [receptor-associated protein (RAP)], or LDL receptor-related protein (RAP, α2-macroglobulin, lipoprotein lipase, exotoxin-A). None of these substances, with the exception of dextran sulphate, influenced binding of LDL to either 105 or 130 kDa proteins. Sodium oleate or oleic acid, known stimuli for the lipoprotein binding activity of the lipolysis-stimulated receptor, were also without effect. LDL binding to 105 and 130 kDa proteins was inhibited by anti-LDL (apo B) antibodies. LDL and VLDL bound to 105 and 130 kDa proteins with similar affinities (蝶50 μg/ml). The unique ligand selectivity of 105 and 130 kDa proteins supports the existence of a novel lipoprotein-binding protein that is distinct from all other currently identified LDL receptor family members. The similar ligand selectivity of 105 and 130 kDa proteins suggests that they may represent variant forms of an atypical lipoprotein-binding protein.

scholarly journals Chinese hamster cell mutant resistant to ML236B (Compactin) is defective in endocytosis of low-density lipo-protein.

1982 ◽  
Vol 2 (11) ◽  
pp. 1354-1361 ◽  
Author(s):  
A Masuda ◽  
S Akiyama ◽  
M Kuwano
Keyword(s):  
Coenzyme A ◽  
Spontaneous Mutation ◽  
Low Density Lipoprotein ◽  
Chinese Hamster ◽  
Specific Inhibitor ◽  
Density Lipoprotein ◽  
Chinese Hamster Cell ◽  
Cellular Level ◽  
Low Density ◽  
Coenzyme A Reductase

A fungal metabolite, ML236B (Compactin), isolated from Penicillium citrinum, is a specific inhibitor of 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A reductase (EC 1.1.1.34). Three ML236B-resistant (ML236Br) mutants, MF-1, MF-2, and MF-3, were isolated from V79 after N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. The fluctuation test showed 2.2 X 10(-6) mutants per cell per generation of a spontaneous mutation frequency of ML236Br clones. These ML236Br clones showed a four- to fivefold-higher resistance to the drug than did their parental V79. Radioactive acetate, but not mevalonate, incorporation into the sterol fraction increased about 10-fold in ML236Br clones in comparison with that in V79. The cellular level of HMG-coenzyme A reductase in three ML236Br mutants was found to be a few-fold higher than that of V79 when cultured in the presence of lipoproteins. The 125I-labeled low-density lipoprotein-binding assay showed binding activity in three ML236Br clones comparable to that of the parental V79 cells. By contrast, an internalization assay of 125I-labeled low-density lipoprotein into the cells showed significantly reduced activity in three ML236Br clones in comparison with V79.

Monoclonal antibodies can precipitate low-density lipoprotein. I. Characterization and use in determining apolipoprotein B.

1985 ◽  
Vol 31 (10) ◽  
pp. 1654-1658 ◽  
Author(s):  
S Marcovina ◽  
D France ◽  
R A Phillips ◽  
S J Mao
Keyword(s):  
Monoclonal Antibodies ◽  
Apolipoprotein B ◽  
Polyclonal Antibodies ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Radial Immunodiffusion ◽  
Enzyme Linked Immunosorbent Assay ◽  
Low Density ◽  
Apo B ◽  
Blotting Technique

Abstract We produced 20 mouse monoclonal antibodies against human plasma low-density lipoprotein (LDL). Individually they failed to precipitate LDL in agarose gel by the double-immunodiffusion technique; collectively they did, or as few as two combined monoclonal antibodies could do so. To mimic polyclonal antibodies in determination of apolipoprotein B (apo B) by radial immunodiffusion, a combination of four particular monoclonal antibodies (clones A, B, C, and D) was necessary. We characterized these four clones with respect to temperature dependency, affinity, total binding to 125I-labeled LDL, and specificity to the different species of apolipoprotein B. Two monoclonal antibodies (B and C) bound 100% of 125I-labeled LDL; clones A and D bound 80% and 87%, respectively. All four clones bound maximally to LDL at 4 degrees C. The affinity constants for clones A, B, C, and D were 0.6, 2.1, 3.8, and 2.3 X 10(9) L/mol, respectively. By the Western blotting technique, the four monoclonal antibodies all reacted with the species B-100 and B-74 of apolipoprotein B, and to various degrees with B-48 and B-26. Radial immunodiffusion (chi) and direct enzyme-linked immunosorbent assay (y) with a mixture of the four monoclonal antibodies gave almost identical results for 70 patients: y = 0.921 chi-2.58; r = 0.933.

Sialic acid content of low-density lipoprotein in women with coronary artery disease

2000 ◽  
Vol 136 (2) ◽  
pp. 110-115 ◽  
Author(s):  
Nina Lindbohm ◽  
Helena Gylling ◽  
Radhakrishnan A. Rajaratnam ◽  
Tatu A. Miettinen
Keyword(s):  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Sialic Acid ◽  
Acid Content ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Sialic Acid Content ◽  
Artery Disease
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