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C Fievet

Publications and source records attributed to C Fievet.

At least 55 records · Page 3Linked to original sources
PubMed1988

Human apolipoprotein B. Evidence for its immunochemical heterogeneity using monoclonal antibodies and an immunoenzymometric assay.

Predefined monoclonal antibodies (Mabs) were used in an immunoenzymometric assay to study the immunochemical heterogeneity of lipoproteins and to search for potential epitopes with pathological importance. By measuring apolipoprotein B (apo B) epitopes in patients with and without angiographically documented coronary artery disease and in patients with type IIa hyperlipoproteinemia, we have found that both types of patients have a significant increase in Apo B-containing particles specifically recognized by one Mab (BL3). We have also observed that the effects of fenofibrate on type IIa patients vary greatly depending on the plasma concentrations of various Apo B-containing lipoproteins. The greatest effects occurred in patients with epitopes recognized by BL3. Lastly, by sequential precipitation of specific epitopes by BL3, we have obtained evidence that the residual epitope(s) may be related to one or more lipoprotein particles.

Antibodies, Monoclonal↗
PubMed1988

Interaction of LDL, Lp[a], and reduced Lp[a] with monoclonal antibodies against apoB.

Five monoclonal antibodies (2A, 9A, 6B, L3, L7) produced in mice against human apolipoprotein B were investigated by competitive and inhibitive electroimmunoassay (EIA) for their reactivity with low density lipoprotein (LDL), lipoprotein[a] (Lp[a]), and reduced Lp[a]. All of the antibodies reacted with apoB of the different lipoproteins indicated by very similar slopes of the binding curves. None of them gave a positive reaction with apolipoprotein[a]. The amount of apoB required for 50% inhibition of antibody binding varied for the different antibodies and lipoproteins. Antibody 9A showed almost the same affinity for LDL, Lp[a], and reduced Lp[a]. Antibodies 2A and 6B bound about twofold better to LDL and reduced Lp[a] than to untreated Lp[a]. Antibodies L3 and L7 needed nearly threefold higher amounts of Lp[a]-apoB for 50% inhibition of antibody binding than of apoB of LDL and reduced Lp[a]. The amount of apoB required for 50% inhibition of antibody binding was somewhat higher in inhibitive assay than in competitive assay. We suggest that apo[a] covers certain epitopes of apoB in native Lp[a] leading to a reduced reaction with the monoclonal antibodies. However, it could also be that the binding of the [a]antigen to apoB via disulfide bridges causes profound conformational changes of the apoB region exposed to the surface.

Adolescent↗
PubMed1988

Electroimmuno- and immunonephelometric assays of apolipoprotein A-I by using a mixture of monoclonal antibodies.

The use of mixtures of well-defined monoclonal antibodies may represent a step forward in the standardization of immunochemical assays. We developed and optimized working conditions for using such a mixture to determine apolipoprotein A-I in human sera by two independent techniques (electroimmuno- and immunonephelometric-assays). Six monoclonal antibodies, each addressed to distinct epitopes located at the surface of apolipoprotein A-I, were used in combination to permit a reproducible measurement of the protein, without prior delipidation of samples. Parallel standard curves for a high-density lipoprotein subfraction (HDL3, the primary standard) and a reference serum (the secondary standard) were obtained. Within- and between-run coefficients of variation were acceptable for both methods. Apolipoprotein A-I concentrations, as measured in 60 subjects selected to present a large range of apolipoprotein content by electroimmunoassay (y1) and immunonephelometric assay (y2) with monoclonal antibodies, compared well with those measured by the same techniques but with polyclonal antibodies (x): r1 = 0.96, r2 = 0.99; y1 = 1.19x - 0.11 g/L, y2 = 0.98x. Comparison of results obtained by electroimmunoassay and immunonephelometric assay performed with monoclonal antibodies was also good: r = 0.96; y2 = 1.08y1 + 0.13 g/L.

Antibodies, Monoclonal↗
PubMed1987

Effect of fenofibrate treatment on type III hyperlipoproteinemia.

The effect of treatment with fenofibrate was investigated in nine patients (seven men) presenting with type III hyperlipoproteinemia. This therapy produced a statistically significant decrease in serum triglyceride, cholesterol, apolipoproteins B, CII, CIII, and E levels. Particular attention was focused on lipoproteins containing apolipoprotein B. The concentration of particles recognized by monoclonal antibodies (BL3, BL5, and BL7), associated with atherosclerotic disease, was lowered by the treatment. The most dramatic decrease was observed for lipoproteins LpE:B and LpCIII:B, which are particularly enhanced in type III hyperlipoproteinemia.

Adult↗
PubMed1987

Detection of human apolipoprotein B polymorphic species with one monoclonal antibody (BIP 45) against low density lipoprotein. Influence of this polymorphism on lipid levels and coronary artery stenosis.

The immunoreactivity of apolipoprotein B (apo B) in plasma samples obtained from a variety of subjects was analysed by non-competitive ELISA with a polyclonal and a monoclonal (BIP 45) anti-LDL antibody. Three populations were tested: the first, comprising 244 healthy male volunteers, provided reference values; the second consisted of a population undergoing coronary angiography (n = 88) and was divided into a subgroup with (n = 64) and without (n = 24) coronary artery disease (CAD); the third was made up of 56 patients with heterozygous familial hypercholesterolemia. Total apo B (measured with the polyclonal antibody) was increased in the populations with CAD and in the heterozygous familial hypercholesterolemic subjects compared to the reference population. When monoclonal antibody BIP 45 was used in the non-competitive ELISA, three different patterns emerged in each population, corresponding to weak, intermediate and strong binding of the particles containing apo B to the monoclonal antibody. This may result from genetic polymorphism of apo B, and in the reference population the data fit a model consisting of two co-dominant apo B alleles (BIP(-) and BIP(+]; the 3 subpopulations then correspond to the 2 homozygotes and the heterozygote. The number of patients whose particles bound weakly to monoclonal BIP 45 antibody was low in the CAD population, while intermediate binding was increased in this group. Nevertheless, when the analysis of variance of allele BIP(-) was studied no significant difference between groups was established. This finding indicates that the genetic difference in apo B detected by BIP 45 may not be significant in the development of CAD. Furthermore, the apo B genetic polymorphism detected by BIP 45 is not associated with a particular lipoprotein level in the reference population.

Animals↗
PubMed1986

Quantitation of human serum apolipoprotein B by enzyme immunoassay in excess antigen.

A solid phase enzyme-linked immunoassay based on the 'sandwich' principle was developed for quantitative measurement of apolipoprotein B (Apo B) in human normal or hyperlipoproteinemic sera. The solid phase (polypropylene multi-finned sticks) coated with an excess of sheep anti-Apo B immunoglobulins was incubated with antigen (standards and unknown specimens) and affinity-purified anti-Apo B antibodies conjugated with horseradish peroxidase. In this principle, antigen and conjugate were in excess and fixed amount respectively. A part of antigen was fixed on multi-finned sticks, bound or not to conjugate. Unbound materials were removed by washing. Solid phases were next incubated with the enzyme substrate solution to develop a color which is inversely related to the amount of Apo B. The best technical conditions for the assay were determined. The method was characterized according to precision, sensitivity and accuracy. It yielded values that compared favorably with those obtained by another enzyme-linked immunoassay and by electroimmunoassay.

Apolipoproteins B↗
PubMed1985

Development of a radial immunodiffusion technique employing monoclonal antibodies for apolipoprotein B determination in human plasma.

Twenty monoclonal antibodies obtained from two different fusions of SP2/0-Ag 14 cell line (non-secretor hybridoma) with human plasma low density lipoproteins have been selected. We found that a mixture formed by the 20 monoclonal antibodies was able to form a single precipitin line with human plasma low density lipoproteins by a double gel diffusion technique. Further studies revealed that only two monoclonal antibodies were needed to precipitate low density lipoproteins in gel. However, a minimum of four particular monoclonal antibodies was required to obtain an optimal precipitin ring and a linear standard curve within 24 h using a radial immunodiffusion technique. We have then compared the radial immunodiffusion performed with a monoclonal antibody mixture to those employing conventional goat and rabbit antibodies in terms of plasma apolipoprotein B determinations. The apolipoprotein B values determined by monoclonal antibodies significantly correlate with the values obtained by the technique using goat (r = 0.95; p less than 0.001) and rabbit (r = 0.95; p less than 0.001) antibodies. Our data indicate that a mixture of monoclonal antibodies can mimic conventional antibodies in terms of immunoprecipitation and apolipoprotein B determination.

Animals↗
PubMed1985

Quantification of apolipoprotein C-III in serum by a noncompetitive immunoenzymometric assay.

We used a noncompetitive immunoenzymometric assay to measure the concentration of total apolipoprotein C-III in human sera. Affinity-purified antibodies to apolipoprotein C-III were adsorbed to the surface of microtiter plates. After washing, this solid-phase antibody was incubated with antigen (serum from fasting subjects), washed, and then incubated with peroxidase-labeled purified antibodies to apolipoprotein C-III. After a last washing, the bound label was assayed, providing a direct measurement of the antigen. Optimized technical conditions for the assay yielded assay CVs of 3.5 and 5.6% for within- and between-run precision, respectively. Analytical recovery of apolipoprotein C-III added to a serum was quantitative (97%). This noncompetitive assay can be used to measure apolipoprotein C-III in different lipoprotein fractions (very-low or high-density fractions) and yields values that compare favorably with those obtained by electroimmunoassay (r = 0.94). The assay offers several advantages over existing techniques--sensitivity, specificity, simplicity, and no use of radioisotopes--and hyperlipemic samples can be used.

Apolipoprotein C-III↗
PubMed1984

Noncompetitive enzyme-linked immunoassay for apolipoprotein B in serum.

We used a noncompetitive enzyme-linked immunoassay to measure apolipoprotein B (apo-B) concentration in human plasma. Goat anti-lipoprotein B immunoglobulins were adsorbed to the surface of polystyrene balls. After washing, this solid-phase antibody was incubated with antigen (plasma from normal or hyperlipoproteinemic fasting subjects), washed, and then incubated with peroxidase-labeled goat anti-lipoprotein B IgG. After a last washing, we measured the bound label, which provided a direct measurement of the antigen. Under optimized assay conditions, the minimum detectable concentration was 50 ng per assay. The assay may be used to measure apo-B in different lipoprotein fractions (low- or very-low-density) and yields values that compared favorably with those obtained by electroimmunoassay (r = 0.86). The assay offers several advantages over existing techniques: sensitivity, specificity, simplicity, avoidance of radioisotopes, and potential for use with monoclonal antibodies.

Apolipoproteins↗