http://www.bibsonomy.org/burst/user/biblio24/apobBibSonomy BuRST Feed for /user/biblio24/apob2008-07-21T00:51:32+02:00http://www.bibsonomy.org/bibtex/27675a344577e2612ea3a271a5010d6e4/biblio24biblio242006-07-07T01:10:50+02:00ldl hdl apob cholesterol <span style="color:#555555;">T. <a href="http://www.bibsonomy.org/author/Pischon">Pischon</a> and C. J. <a href="http://www.bibsonomy.org/author/Girman">Girman</a> and F. M. <a href="http://www.bibsonomy.org/author/Sacks">Sacks</a> and N. <a href="http://www.bibsonomy.org/author/Rifai">Rifai</a> and M. J. <a href="http://www.bibsonomy.org/author/Stampfer">Stampfer</a> and E. B. <a href="http://www.bibsonomy.org/author/Rimm">Rimm</a> </span><em>Circulation</em><em>112(22):3375--3383</em><em>November2005. </em>Fri Jul 07 01:10:50 CEST 2006Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA. pischon@mail.dife.deCirculationNovember223375--3383Non-high-density lipoprotein cholesterol and apolipoprotein B in the prediction of coronary heart disease in men.1122005ldl hdl apob cholesterol BACKGROUND: Apolipoprotein B (apoB) plasma levels reflect the concentration of proatherogenic lipoproteins very low-density lipoprotein and low-density lipoprotein (LDL), whereas non-high-density lipoprotein cholesterol (non-HDL-C) levels reflect the concentration of cholesterol transported by these particles. METHODS AND RESULTS: The aim of our study was to compare apoB, non-HDL-C, LDL cholesterol (LDL-C), and other lipid markers as predictors of coronary heart disease (CHD) in a nested case-control study among 18 225 participants in the Health Professionals Follow-up Study. Among men who were free of diagnosed cardiovascular disease at the time of blood collection, 266 had nonfatal myocardial infarction or fatal CHD during 6 years of follow-up. Through the use of risk set sampling, control subjects were selected at a 2:1 ratio and matched with regard to age, date of blood collection, and smoking status. After adjustment for matching factors, the relative risk of CHD in the highest quintile compared with the lowest quintile was 2.76 (95% confidence interval [CI], 1.66 to 4.58) for non-HDL-C, 3.01 (95% CI, 1.81 to 5.00) for apoB, 1.81 (95% CI, 1.12 to 2.93) for LDL-C, 0.31 (95% CI, 0.18 to 0.52) for HDL-C, 2.41 (95% CI, 1.43 to 4.07) for triglycerides (all P trend <0.001), and 1.42 (95% CI, 0.86 to 2.32, P trend =0.19) for lipoprotein(a). When non-HDL-C and LDL-C were mutually adjusted, only non-HDL-C was predictive of CHD. When non-HDL-C and apoB were mutually adjusted, only apoB was predictive; the relative risk was 4.18 (95% CI, 1.30 to 13.49; P trend =0.02) for apoB compared with 0.70 (95% CI, 0.21 to 2.27; P trend =0.72) for non-HDL-C. Triglycerides added significant information to non-HDL-C but not to apoB for CHD risk prediction. CONCLUSIONS: Although non-HDL-C and apoB were both strong predictors of CHD in this male cohort, more so than LDL-C, the findings support the concept that the plasma concentration of atherogenic lipoprotein particles measured by apoB is more predictive in development of CHD than the cholesterol carried by these particles, measured by non-HDL-C.http://www.bibsonomy.org/bibtex/278d0961a88d7bb0e58a008fae172537d/biblio24biblio242006-07-07T01:10:50+02:00diagnosis review hypertg apob <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Sniderman">Sniderman</a> and K. <a href="http://www.bibsonomy.org/author/Williams">Williams</a> and S. <a href="http://www.bibsonomy.org/author/Haffner">Haffner</a> and N. <a href="http://www.bibsonomy.org/author/Sattar">Sattar</a> </span><em>Atheroscler Suppl</em><em>5(2):19--24</em><em>May2004. </em>Fri Jul 07 01:10:50 CEST 2006Mike Rosenbloom Laboratory for Cardiovascular Research, McGill University Health Center, Royal Victoria Hospital, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada. allan.sniderman@muhc.mcgill.caAtheroscler SupplMay219--24Insights from apoB: from better diagnosis \& therapy to the Medusa Hypothesis.52004diagnosis review hypertg apob This article will review six of the most important insights that have come from the measurement of apolipoprotein B (apoB). Amongst these are critical clinical advances, which include better definition of those at high risk of vascular disease and better definition of the adequacy of statin therapy. There are also major advances in our understanding of the fundamental processes that interact to cause vascular disease. These include a more precise understanding of the determinants of lipoprotein levels and lipoprotein composition in plasma and, even more importantly, an appreciation of the pivotal role excess fatty acid intake and impaired fatty acid trapping by adipose tissue play in the generation of the complex risk profile that is so common in patients with coronary disease. We have designated the constellation of hypertriglyceridemic (hyperTg) hyperapoB, dysglycemia, and elevated levels of markers of prothrombosis and inflammation--all of which are traceable to adipose tissue dysfunction--as the Medusa Hypothesis. The Medusa Hypothesis puts forward a common pathophysiology for the complex and biologically diverse array of factors that have been associated with vascular disease.http://www.bibsonomy.org/bibtex/23b276b6d9c5e4fa8354929c4c75466b1/biblio24biblio242006-07-07T01:10:50+02:00review apob <span style="color:#555555;">U. <a href="http://www.bibsonomy.org/author/Julius">Julius</a> </span><em>Exp Clin Endocrinol Diabetes</em><em>111(5):246--250</em><em>August2003. </em>Fri Jul 07 01:10:50 CEST 2006Medical Clinic and Outpatient Department III, University Hospital at the University of Technology, Dresden, Germany. julius@rcs.urz.tu-dresden.deExp Clin Endocrinol DiabetesAugust5246--250Influence of plasma free fatty acids on lipoprotein synthesis and diabetic dyslipidemia.1112003review apob The regulation of hepatic VLDL secretion mainly depends on apolipoprotein (apo) B synthesis, on microsomal triglyceride transfer protein, insulin and the availability of triglycerides, free fatty acids (FFA) and cholesteryl ester. Four sources of fatty acids are used for lipoprotein synthesis: de-novo lipogenesis, cytoplasmic triglyceride stores, fatty acids derived from lipoproteins taken up directly by the liver and plasma FFA. Quantitatively, de-novo lipogenesis plays a minor role in regulating VLDL synthesis, but evidently it is elevated under conditions of high carbohydrate feeding. Cytoplasmic triglyceride stores appear to essentially contribute to VLDL triglycerides. Plasma FFA enter the hepatocytes and are either oxidized or esterified. The relationship between oxidation and esterification appears to be important in regulating the VLDL synthesis. An enhanced esterification is accompanied by increased VLDL secretion. The addition of oleic acid to hepatocytes has been shown to stimulate production of VLDL triglyceride and apoB. In human beings, an acute experimental elevation of plasma FFA stimulates VLDL production. In healthy men strong positive relations were found between the late increases in large triglyceride-rich lipoproteins and plasma FFA concentrations after 6 h following a mixed meal. In contrast, n-3 fatty acids impair VLDL assembly and secretion. Chronic hyperinsulinemia seems to stimulate VLDL production. On the other hand, the short-term addition of insulin has been shown to inhibit VLDL-triglyceride and apoB production in vitro. There is in vivo evidence that acute hyperinsulinemia suppresses VLDL-apoB and VLDL-triglyceride production in insulin-sensitive humans. Part of this action is due to suppression of plasma FFA. In patients with impaired glucose tolerance (IGT), VLDL production was increased when compared with subjects with normal glucose (NGT). When infusing a lipid emulsion, VLDL production could not be further stimulated in IGT patients in contrast to NGT persons. Hypertriglyceridemia in type 2 diabetes mellitus is usually the consequence of a VLDL overproduction. In type 2 diabetic patients, in contrast to normal men, insulin failed to suppress VLDL1 particle release. In normal men, an elevation of blood glucose led to a decrease in fatty acid oxidation and an increase in hepatic triglyceride secretion. Under these conditions, approximately 30% of total VLDL triglycerides coming out of the liver did not originate from plasma FFA. In conclusion, plasma FFA seem to play an important role in stimulating hepatic VLDL production. Other factors such as chronic hyperinsulinemia or nutrition modify this effect.http://www.bibsonomy.org/bibtex/2fb49b99efdbb81d2c6551acac9f3771d/biblio24biblio242006-07-07T01:10:50+02:00clinical hyperchol apob hypertg review diagnosis statin <span style="color:#555555;">A. D. <a href="http://www.bibsonomy.org/author/Sniderman">Sniderman</a> </span><em>Am J Cardiol</em><em>October2002. </em>Fri Jul 07 01:10:50 CEST 2006Mike Rosenbloom Laboratory for Cardiovascular Research, McGill University Health Centre, Laboratory for Cardiovascular Research, Royal Victoria Hospital, Montreal, Quebec, Canada. allan.sniderman@muhc.mcgill.caAm J CardiolOctober8AHow, when, and why to use apolipoprotein B in clinical practice.902002clinical hyperchol apob hypertg review diagnosis statin The evidence is now clear that plasma apolipoprotein (apo) B is a better index of the risk of coronary artery disease (CAD) than total or low-density lipoprotein (LDL) cholesterol. Moreover, the evidence is also clear that clinical risk of apo B is determined not only by LDL particle number but also by whether small, dense LDL particles are present. The objective of this article, therefore, is to demonstrate how, when, and why apo B should be used in clinical practice. First, the evidence that apo B is superior to LDL cholesterol as an index of the risk of CAD and as a guide to the adequacy of statin therapy is briefly reviewed. Next, the biological bases for this superiority in identifying risk are outlined. Clinical scenarios are then outlined demonstrating the value of measuring apo B in hypertriglyceridemic, hypercholesterolemic, and normolipidemic subjects.The methodological soundness of the laboratory determinations of lipids and apo B is also an important issue. Concern has been raised regarding the measurement of apo B, but it is standardized, precise, and not expensive. Paradoxically, it is becoming ever more obvious that the methodological problems lie with calculated LDL cholesterol. To the known deficiencies must be added the fact that calculated LDL cholesterol systematically underestimates true LDL cholesterol at values close to target levels.Thus, from every perspective-pathophysiology, diagnosis, assessment of therapy, and methodologic soundness-there are powerful clinical arguments why apo B should be used in the routine diagnosis of dyslipidemias and assessment of the adequacy of statin therapy.http://www.bibsonomy.org/bibtex/2a7762e06e43869ffae0df810f64dd46b/biblio24biblio242006-07-07T01:10:50+02:00review statin apob <span style="color:#555555;">C. <a href="http://www.bibsonomy.org/author/Wanner">Wanner</a> and V. <a href="http://www.bibsonomy.org/author/Krane">Krane</a> and T. <a href="http://www.bibsonomy.org/author/Metzger">Metzger</a> and T. <a href="http://www.bibsonomy.org/author/Quaschning">Quaschning</a> </span><em>J Nephrol</em>(<em>2001</em>)Fri Jul 07 01:10:50 CEST 2006Department of Medicine, Division of Nephrology, University of Würzburg, Germany. c.wanner@medizin.uni-wuerzburg.deJ NephrolLipid changes and statins in chronic renal insufficiency and dialysis.14 Suppl 42001review statin apob Chronic renal failure patients suffer from a secondary form of complex dyslipidemia, similar to the so-called atherogenic dyslipidemia in insulin resistant patients or to diabetic dyslipidemia. The most important abnormalities are an increase in the serum level of triglyceride (elevated VLDL-remnants/IDL), small LDL particles and a low HDL cholesterol. The highly atherogenic LDL subclass, namely LDL-6 or small dense LDL, accumulates in hypertriglyceridemic diabetic hemodialysis patients. All these lipoprotein particles contain apoB, thus much of this complex disorder can be summarized as an elevation of triglyceride-rich apoB containing complex lipoprotein particles. Growing evidence suggests that all of the components of this type of dyslipidemia are independently atherogenic. Further disturbances exist in the dynamics of cholesterol exchange between the various lipoprotein particles and in transport from cells to catabolic sites. The European Joint Task Force and the US National Cholesterol Education Program expert panel have issued guidelines for the general population to lower the cardiovascular risk in hyper- and dyslipidemias. There is preliminary consensus that these guidelines should be applied to dialysis patients. However, the genesis of atherosclerosis in the dialysis population may be different and real benefit from lipid-lowering has not yet been demonstrated in this population. Large-scale, prospective randomized trials (4D-trial, HARP) are underway to determine whether statins reduce cardiovascular complications in diabetic and non-diabetic patients with end-stage renal disease (ESRD) and on hemodialysis treatment.http://www.bibsonomy.org/bibtex/264fee8a74054cacb021a4106ed8baf1f/biblio24biblio242006-07-07T01:10:50+02:00spr epitope mapping apob <span style="color:#555555;">L. <a href="http://www.bibsonomy.org/author/Laricchia Robbio">Laricchia Robbio</a> and P. <a href="http://www.bibsonomy.org/author/Uboldi">Uboldi</a> and S. <a href="http://www.bibsonomy.org/author/Marcovina">Marcovina</a> and R. P. <a href="http://www.bibsonomy.org/author/Revoltella">Revoltella</a> and A. L. <a href="http://www.bibsonomy.org/author/Catapano">Catapano</a> </span><em>Biosens Bioelectron</em><em>16(9-12):963--969</em><em>December2001. </em>Fri Jul 07 01:10:50 CEST 2006Institute of Mutagenesis and Differentiation, CNR, Area della Ricerca San Cataldo, 56100 Via Moruzzi, Ghezzano-Pisa, Italy. lel@imd.pi.cnr.itBiosens BioelectronDecember9-12963--969Epitope mapping analysis of apolipoprotein B-100 using a surface plasmon resonance-based biosensor.162001spr epitope mapping apob Using a surface plasmon resonance (SPR)-based biosensor (BIA-technology), we have studied the interaction of ten different murine monoclonal antibodies (mAbs, all IgG(1)), raised against the main protein constituent of human low density lipoprotein (LDL), i.e. the apolipoprotein B-100 (apoB-100). These mAbs identify distinct domains on apoB-100, relevant to LDL-receptor interaction: epitopes in the amino-terminal region (mAbs L7, L9, L10 and L11: aa 1-1297) and in the middle region (mAb 6B: aa 1480-1693; mAbs 2A, 3B: aa 2152-2377; mAbs 9A, L2 and L4: aa 2657-3248) of native apoB-100. A multisite binding analysis was performed to further characterize the epitopes recognized by all these mAbs. A rabbit anti-mouse IgG(1)-Fc antibody (RAM.Fc) was first coupled to the gold surface in order to capture one anti-human apoB-100 mAb. ApoB-100 protein was subsequently injected and allowed to react with this immobilized, oriented antibody. Multisite binding assays were then performed, by sequentially flowing other mAbs, in different orders, over the sensing surface. The capacity of each mAb to interact with the entrapped apoB-100 in a multimolecular complex was monitored in real time by SPR. The results achieved were comparable to those obtained by western immunoblotting using the same reagents. However, SPR ensures a more detailed epitope identification, demonstrating that BIA-technology can be successfully used for mapping distinct epitopes on apoB-100 protein in solution dispensing with labels and secondary tracers; moreover, compared with conventional immunoassays, it is significantly time saving (CNR-P.F. MADESS 2).http://www.bibsonomy.org/bibtex/28470a55ffd3031830371a1e0072d15bf/biblio24biblio242006-07-07T01:10:50+02:00apob mapping epitope <span style="color:#555555;">S. <a href="http://www.bibsonomy.org/author/Fantappiè">Fantappi&#232;</a> and A. <a href="http://www.bibsonomy.org/author/Corsini">Corsini</a> and A. <a href="http://www.bibsonomy.org/author/Sidoli">Sidoli</a> and P. <a href="http://www.bibsonomy.org/author/Uboldi">Uboldi</a> and A. <a href="http://www.bibsonomy.org/author/Granata">Granata</a> and T. <a href="http://www.bibsonomy.org/author/Zanelli">Zanelli</a> and P. <a href="http://www.bibsonomy.org/author/Rossi">Rossi</a> and S. <a href="http://www.bibsonomy.org/author/Marcovina">Marcovina</a> and R. <a href="http://www.bibsonomy.org/author/Fumagalli">Fumagalli</a> and A. L. <a href="http://www.bibsonomy.org/author/Catapano">Catapano</a> </span><em>Journal of Lipid Research</em><em>33(8):1111--1121</em><em>August1992. </em>Fri Jul 07 01:10:50 CEST 2006Institute of Pharmacological Sciences, University of Milano, Italy.Journal of Lipid ResearchAugust81111--1121Monoclonal antibodies to human low density lipoprotein identify distinct areas on apolipoprotein B-100 relevant to the low density lipoprotein-receptor interaction.331992apob mapping epitope We have characterized the epitopes for ten murine monoclonal antibodies (Mabs) to human low density lipoprotein (LDL) and studied their ability to interfere with the LDL-receptor interaction. The epitopes for the antibodies were defined by using the following approaches: 1) interaction with apoB-48; 2) interaction with apoB-100 thrombolytic fragments; and 3) interaction with beta-galactosidase-apoB fusion proteins spanning different areas of the apoB-100 sequence. The results obtained are consistent with the following map of epitopes: Mab 6E, amino acids (aa) 1-1297, Mabs 5A and 6B, aa 1480-1693, Mabs 2A, 7A, 3B, and 4B, aa 2152-2377, Mabs 8A and 9A, aa 2657-3248 and 3H, aa 4082-4306. Four Mabs (2A, 5A, 7A, and 9A) whose epitopes are located in three different areas of apoB, dramatically reduced (up to 95%) the LDL-receptor interaction on cultured human fibroblasts; Fab fragments were as effective as the whole antibodies. Mab 3H, on the other hand, increased LDL binding up to threefold. These findings are consistent with the hypothesis that several areas of apoB-100 are involved independently or in concert in modulating the apoprotein B conformation required for interaction with the LDL receptor.http://www.bibsonomy.org/bibtex/2168fabbe738c303ba879cabba2132262/biblio24biblio242006-07-07T01:10:50+02:00apob epitope mapping <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Law">Law</a> and J. <a href="http://www.bibsonomy.org/author/Scott">Scott</a> </span><em>Journal of Lipid Research</em><em>31(6):1109--1120</em><em>June1990. </em>Fri Jul 07 01:10:50 CEST 2006Division of Molecular Medicine, Clinical Research Centre, Harrow, Middlesex, UK.Journal of Lipid ResearchJune61109--1120A cross-species comparison of the apolipoprotein B domain that binds to the LDL receptor.311990apob epitope mapping Apolipoprotein (apo)-B-100 is the ligand that mediates the clearance of low density lipoprotein (LDL) from the circulation by the apoB,E (LDL) receptor pathway. Clearance is mediated by the interaction of a domain enriched in basic amino acid residues on apoB-100 with clusters of acidic residues on the apoB,E (LDL) receptor. A model has been proposed for the LDL receptor binding domain of apoB-100 based on the primary amino acid sequence (Knott, T. J., et al. 1986. Nature. 323: 734-738). Two clusters of basic residues (A: 3147-3157 and B: 3359-3367) are apposed on the surface of the LDL particle by a disulfide bridge between Cys 3167 and 3297. Support for this single domain model has been obtained from the mapping of epitopes for anti-apoB monoclonal antibodies that block the binding of apoB to the LDL receptor. Here we test this model by comparing the nucleotide (from 9623 to 10,442) and amino acid sequence (from 3139 to 3411) of apoB-100 in seven species (human, pig, rabbit, rat, Syrian hamster, mouse, and chicken). Overall, this region is highly conserved. Cluster B maintains a strong net positive charge and is homologous across species in both primary and secondary structure. However, the net positive charge of region A is not conserved across these species, but the region remains strongly hydrophilic. The secondary structure of the region between clusters A and B is preserved, but the disulfide bond is unique to the human sequence. This study suggests that the basic region B is primarily involved in the binding of apoB-100 to the apoB,E (LDL) receptor.http://www.bibsonomy.org/bibtex/28d11f0f4ea344a79847956672e32e594/biblio24biblio242006-07-07T01:10:50+02:00apob mapping epitope <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Leroy">Leroy</a> and G. <a href="http://www.bibsonomy.org/author/Castro">Castro</a> and G. <a href="http://www.bibsonomy.org/author/Agnani">Agnani</a> and R. <a href="http://www.bibsonomy.org/author/Saïle">Sa&#239;le</a> and A. <a href="http://www.bibsonomy.org/author/Barkia">Barkia</a> and J. C. <a href="http://www.bibsonomy.org/author/Fruchart">Fruchart</a> </span><em>J Lipid Res</em><em>33(6):889--898</em><em>June1992. </em>Fri Jul 07 01:10:50 CEST 2006SERLIA, Institut Pasteur et INSERM U 279, Lille, France.J Lipid ResJune6889--898Thrombin cleavage of apolipoprotein Bh of rabbit LDL: structural comparisons with human apolipoprotein B-100.331992apob mapping epitope Rabbit plasma low density lipoprotein (LDL) contains one major apolipoprotein of apparent molecular weight of 320 kDa, designated apolipoprotein (apo) Bh, while another component termed apoB1 of apparent molecular weight of 220 kDa is found in chylomicrons. The fragments generated by thrombin digestion of the protein moieties of rabbit and human LDL were separated by polyacrylamide gradient gel electrophoresis and compared. As in the human species, the enzyme produced limited cleavage patterns of rabbit LDL apoB. Within the first 2 h, two fragments (Tr1 and Tr2, with apparent molecular weights 280,000 and 44,000, respectively) appeared. Longer incubations led to the production of two additional peptides, Tr3 and Tr4 (apparent molecular weights 180,000 and 96,000, respectively). Ten monoclonal antibodies, developed against rabbit LDL and designated P01 to P10, were found to react with rabbit apoB. Some also cross-reacted with human apoB. Epitope mapping, performed with these antibodies, showed that Tr3 and Tr4 were derived from the further degradation of Tr1. The rabbit is one of the most frequently used animals in atherosclerosis research. Its LDL receptor has been characterized and there exists a strain of homozygous LDL receptor-deficient rabbits referred to as WHHL rabbits. Despite this, little has been done to characterize the structure of rabbit apoB; only a short region has been sequenced and shown to be the carboxyl-terminal region, the rabbit apoB1. The molecular weight of human apoB (550,000) is much larger than rabbit apoBh. In both species, a primary and secondary thrombin cleavage occur, but the size of the fragments produced is very different between the two species. Identification of the thrombolytic fragments of the rabbit apoB have afforded the opportunity to compare the structures of both apoB species.http://www.bibsonomy.org/bibtex/22ce679c5f6641476344be6928398ae71/biblio24biblio242006-07-07T01:10:50+02:00epitope apob mapping <span style="color:#555555;">R. <a href="http://www.bibsonomy.org/author/Milne">Milne</a> and R. <a href="http://www.bibsonomy.org/author/Théolis">Th&#233;olis</a> and R. <a href="http://www.bibsonomy.org/author/Maurice">Maurice</a> and R. J. <a href="http://www.bibsonomy.org/author/Pease">Pease</a> and P. K. <a href="http://www.bibsonomy.org/author/Weech">Weech</a> and E. <a href="http://www.bibsonomy.org/author/Rassart">Rassart</a> and J. C. <a href="http://www.bibsonomy.org/author/Fruchart">Fruchart</a> and J. <a href="http://www.bibsonomy.org/author/Scott">Scott</a> and Y. L. <a href="http://www.bibsonomy.org/author/Marcel">Marcel</a> </span><em>The Journal of Biological Chemistry</em><em>264(33):19754--19760</em><em>November1989. </em>Fri Jul 07 01:10:50 CEST 2006Laboratory of Lipoprotein Metabolism, Institut de Recherches Cliniques de Montréal, Quebec, Canada.The Journal of Biological ChemistryNovember3319754--19760The use of monoclonal antibodies to localize the low density lipoprotein receptor-binding domain of apolipoprotein B.2641989epitope apob mapping Human apolipoprotein (apo) B-100 is composed of 4536 amino acids. It is thought that the binding of apoB to the low density lipoprotein (LDL) receptor involves an interaction between basic amino acids of the ligand and acidic residues of the receptor. Three alternative models have been proposed to describe this interaction: 1) a single region of apoB is involved in receptor binding; 2) groups of basic amino acids from throughout the apoB primary structure act in concert in apoB receptor binding; and 3) apoB contains multiple independent binding regions. We have found that monoclonal antibodies (Mabs) specific for a region that spans a thrombin cleavage site at apoB residue 3249 (T2/T3 junction) totally blocked LDL binding to the LDL receptor. Mabs specific for epitopes outside this region had either no or partial ability to block LDL binding. In order to define the region of apoB directly involved in the interaction with the LDL receptor we have tested 22 different Mabs for their ability to bind to LDL already fixed to the receptor. A Mab specific for an epitope situated between residues 2835 and 2922 could bind to its epitope on LDL fixed to its receptor whereas a second epitope between residues 2980 and 3084 is inaccessible on receptor-bound LDL. A series of epitopes near residue 3500 of apoB is totally inaccessible, and another situated between residues 4027 and 4081 is poorly accessible on receptor-bound LDL. In contrast, an epitope that is situated between residues 4154 and 4189 is fully exposed. Mabs specific for epitopes upstream and downstream of the region 3000-4000 can bind to receptor-bound LDL with a stoichiometry close to unity. Our results strongly suggest that the unique region of apoB directly involved in the LDL-receptor interaction is that of the T2/T3 junction.http://www.bibsonomy.org/bibtex/23b05a4543a044aec50b7c949a22dab22/biblio24biblio242006-07-07T01:10:50+02:00epitope apob mapping <span style="color:#555555;">P. F. <a href="http://www.bibsonomy.org/author/Chen">Chen</a> and Y. L. <a href="http://www.bibsonomy.org/author/Marcel">Marcel</a> and C. Y. <a href="http://www.bibsonomy.org/author/Yang">Yang</a> and A. M. <a href="http://www.bibsonomy.org/author/Gotto">Gotto</a> and R. W. <a href="http://www.bibsonomy.org/author/Milne">Milne</a> and J. T. <a href="http://www.bibsonomy.org/author/Sparrow">Sparrow</a> and L. <a href="http://www.bibsonomy.org/author/Chan">Chan</a> </span><em>European Journal of Biochemistry</em><em>175(1):111--118</em><em>July1988. </em>Fri Jul 07 01:10:50 CEST 2006Department of Medicine, Baylor College of Medicine, Houston, Texas 77030.European Journal of BiochemistryJuly1111--118Primary sequence mapping of human apolipoprotein B-100 epitopes. Comparisons of trypsin accessibility and immunoreactivity and implication for apoB conformation.1751988epitope apob mapping Differential trypsin-accessibility and monoclonal antibodies (Mabs) to human apolipoprotein (apo) B-100 are both important tools for probing apoB structure and conformation on low-density lipoproteins (LDL). In this study, we have mapped greater than 80% of the C-terminal region (720 residues) of LDL apoB-100 using trypsin digestion. Our results extend our previous data [Yang et al. (1986) Nature (Lond.) 323, 738-742] confirming that the C-terminal region of about 420 residues of apoB-100 is largely inaccessible to trypsin, whereas the part just preceding this region has interspersed trypsin-accessible and inaccessible peptides. We have determined the amino acid sequence of specific apoB-100 peptides containing epitopes recognized by four separate Mabs: two epitopes have been mapped to within 20 residues, one has been mapped to 36 residues, and the last to 80 residues. We used polyclonal antisera to identify 16 overlapping clones of varying lengths of apoB-100 cDNAs extending from the C-terminus of apoB-100 cloned in the expression vector, lambda gt11. These clones were then tested against individual Mabs. By nucleotide sequence analysis of overlapping clones that show differential reactivities to different Mabs, we have mapped the individual epitopes of each Mab to within about 50-150 amino acid residues predicted from the DNA sequences. Confirmation and further fine mapping were accomplished by competition for LDL binding using partially purified fusion proteins and chemically synthesized oligopeptides. Two epitopes (Mabs 7 and 22) were mapped to the C-terminal 20 amino acids of apoB-100, one (Mab 16) to residues 4154-4189, and another (Mab 20) to residues 3926-4005. Mab 16 precipitates more than 80% of LDL particles. Mab 20 precipitates only denatured apoB but not native LDL apoB [Milne et al. (1987) Mol. Immunol. 24, 435]. Mabs 7 and 22 are unique in that they precipitate LDL apoB modified by storage much better than freshly isolated LDL-apoB. Although epitope expression and trypsin-accessibility represent two useful probes for the study of protein conformation, there was no obvious correlation between these two parameters when applied to LDL apoB for the antibodies we have examined.http://www.bibsonomy.org/bibtex/2e411d814ee7eddf310743ec95ad27d82/biblio24biblio242006-07-07T01:10:50+02:00apob immunoassay <span style="color:#555555;">Md <a href="http://www.bibsonomy.org/author/Curry">Curry</a> and A. <a href="http://www.bibsonomy.org/author/Gustafson">Gustafson</a> and P. <a href="http://www.bibsonomy.org/author/Alaupovic">Alaupovic</a> and Wj <a href="http://www.bibsonomy.org/author/Mcconathy">Mcconathy</a> </span><em>Clin Chem</em><em>24(2):280--286</em><em>February1978. </em>Fri Jul 07 01:10:50 CEST 2006Clin ChemFebruary2280--286Electroimmunoassay, radioimmunoassay, and radial immunodiffusion assay evaluated for quantification of human apolipoprotein B241978apob immunoassay http://www.bibsonomy.org/bibtex/2c2f02dd34a1c927e4d1496d639f195f1/biblio24biblio242006-07-07T01:10:50+02:00apob epitope mapping <span style="color:#555555;">A. <a href="http://www.bibsonomy.org/author/Gries">Gries</a> and C. <a href="http://www.bibsonomy.org/author/Fievet">Fievet</a> and S. <a href="http://www.bibsonomy.org/author/Marcovina">Marcovina</a> and J. <a href="http://www.bibsonomy.org/author/Nimpf">Nimpf</a> and H. <a href="http://www.bibsonomy.org/author/Wurm">Wurm</a> and H. <a href="http://www.bibsonomy.org/author/Mezdour">Mezdour</a> and J. C. <a href="http://www.bibsonomy.org/author/Fruchart">Fruchart</a> and G. M. <a href="http://www.bibsonomy.org/author/Kostner">Kostner</a> </span><em>J Lipid Res</em><em>29(1):1--8</em><em>January1988. </em>Fri Jul 07 01:10:50 CEST 2006Institute of Physiology, University of Graz, Austria.J Lipid ResJanuary11--8Interaction of LDL, Lp[a], and reduced Lp[a] with monoclonal antibodies against apoB.291988apob epitope mapping 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.http://www.bibsonomy.org/bibtex/277181e1e36e463d480884749cef04545/biblio24biblio242006-07-07T01:10:50+02:00mapping epitope apob <span style="color:#555555;">X. <a href="http://www.bibsonomy.org/author/Wang">Wang</a> and R. <a href="http://www.bibsonomy.org/author/Bucala">Bucala</a> and R. <a href="http://www.bibsonomy.org/author/Milne">Milne</a> </span><em>Proc Natl Acad Sci U S A</em><em>95(13):7643--7647</em><em>June1998. </em>Fri Jul 07 01:10:50 CEST 2006Lipoprotein and Atherosclerosis Group, University of Ottawa Heart Institute, Ottawa, ON, Canada K1Y 4E9.Proc Natl Acad Sci U S AJune137643--7647Epitopes close to the apolipoprotein B low density lipoprotein receptor-binding site are modified by advanced glycation end products.951998mapping epitope apob Advanced glycation end products (AGEs) are thought to contribute to the abnormal lipoprotein profiles and increased risk of cardiovascular disease of patients with diabetes and renal failure, in part by preventing apolipoprotein B (apoB)-mediated cellular uptake of low density lipoproteins (LDL) by LDL receptors (LDLr). It has been proposed that AGE modification at one site in apoB, almost 1,800 residues from the putative apoB LDLr-binding domain, may be sufficient to induce an apoB conformational change that prevents binding to the LDLr. To further explore this hypothesis, we used 29 anti-human apoB mAbs to identify other potential sites on apoB that may be modified by in vitro advanced glycation of LDL. Glycation of LDL caused a time-dependent decrease in its ability to bind to the LDLr and in the immunoreactivity of six distinct apoB epitopes, including two that flank the apoB LDLr-binding domain. ApoB appears to be modified at multiple sites by these criteria, as the loss of glycation-sensitive epitopes was detected on both native glycated LDL and denatured, delipidated glycated apoB. Moreover, residues directly within the putative apoB LDLr-binding site are not apparently modified in glycated LDL. We propose that the inability of LDL modified by AGEs to bind to the LDLr is caused by modification of residues adjacent to the putative LDLr-binding site that were undetected by previous immunochemical studies. AGE modification either eliminates the direct participation of the residues in LDLr binding or indirectly alters the conformation of the apoB LDLr-binding site.http://www.bibsonomy.org/bibtex/20c871b9efb66a25cb92ee7b93cfa8622/biblio24biblio242006-07-07T01:10:50+02:00apob mapping epitope <span style="color:#555555;">S. G. <a href="http://www.bibsonomy.org/author/Young">Young</a> and R. K. <a href="http://www.bibsonomy.org/author/Koduri">Koduri</a> and R. K. <a href="http://www.bibsonomy.org/author/Austin">Austin</a> and D. J. <a href="http://www.bibsonomy.org/author/Bonnet">Bonnet</a> and R. S. <a href="http://www.bibsonomy.org/author/Smith">Smith</a> and L. K. <a href="http://www.bibsonomy.org/author/Curtiss">Curtiss</a> </span><em>Journal of Lipid Research</em><em>35(3):399--407</em><em>March1994. </em>Fri Jul 07 01:10:50 CEST 2006Gladstone Institute for Cardiovascular Disease, Department of Medicine, University of California, San Francisco 94141-9100.Journal of Lipid ResearchMarch3399--407Definition of a nonlinear conformational epitope for the apolipoprotein B-100-specific monoclonal antibody, MB47.351994apob mapping epitope The apolipoprotein (apo) B-100-specific monoclonal antibody MB47 has been widely used in lipoprotein metabolism and atherosclerosis research. When bound to apoB-100 on low density lipoproteins (LDL), antibody MB47 completely blocks the binding of LDL to the LDL receptor. The epitope for antibody MB47 has previously been mapped to the vicinity of apoB-100 amino acid (aa) residue 3500. To map the epitope for antibody MB47 more precisely, we used recombinant bacterial fusion proteins. Antibody MB47 bound strongly to a fusion protein containing apoB-100 aa 3214-3728, but no specific binding was observed to fusion proteins containing aa 3214-3351, 3214-3506, 3351-3506, or a fusion protein containing aa 3214-3351 and 3506-3728. Although antibody MB47 did not bind to aa 3214-3506, it did bind to aa 3214-3510. Further fusion protein studies revealed that antibody MB47 bound to aa 3429-3510, but bound only very weakly to aa 3453-3510, indicating that aa 3429-3453 constitute an important part of the MB47 epitope. Subsequent fusion protein studies revealed that MB47 bound much more strongly to aa 3429-3523, 3429-3544, 3429-3565, and 3429-3590 than to aa 3429-3510. Thus, aa 3507-3523 also constitute an important part of the MB47 epit0pe. m In summary, the fusion protein data indicated that two nonlinear domains of apoB-100 separated by - 53 aa (the 25 residues from aa 3429 to 3453 and the 17 residues from aa 3507 to 3523) form key parts of the MB47 epitope. Antibody MB47 failed to bind to any of 15 different synthetic apoB peptides that spanned aa 3415-3510, a finding that is consistent with the fusion protein data indicating that the MB47 epitope is formed by the conformational alignment of discontinuous amino acid sequences.http://www.bibsonomy.org/bibtex/2e14ee9c0edf81e44b4597a63373ee56f/biblio24biblio242006-07-07T01:10:50+02:00mapping epitope apob <span style="color:#555555;">L. <a href="http://www.bibsonomy.org/author/Viens">Viens</a> and L. <a href="http://www.bibsonomy.org/author/Lagrost">Lagrost</a> </span><em>J Lipid Res</em><em>38(6):1129--1138</em><em>June1997. </em>Fri Jul 07 01:10:50 CEST 2006Laboratoire de Biochimie de Lipoprotéines, INSERM CJF 93-10, Faculté de Médecine, Dijon, France.J Lipid ResJune61129--1138Effect of lipid transfer activity and triglyceride hydrolysis on apolipoprotein B immunoreactivity in modified low density lipoproteins.381997mapping epitope apob Consequences of alterations in the size and the lipid composition of low density lipoproteins (LDL) on apolipoprotein (apo) B immunoreactivity were analyzed using two distinct anti-apoB monoclonal antibodies (Mabs), i.e., 4G3, which recognizes an epitope closed to the binding site to the LDL receptor, and 2D8, which is directed against a distal region. Inhibition analysis revealed that the lipid transfer-mediated triglyceride enrichment of LDL isolated from 12 native human plasmas is associated with significant reductions in the expression of 2D8 and 4G3 epitopes (P < 0.05 in both cases). In contrast, triglyceride hydrolysis of triglyceride-rich LDL significantly increased apoB immunoreactivity as compared with non-lipolyzed counterparts (P < 0.05 with 2D8 and 4G3 Mabs). Among all the modified LDL fractions studied (n = 36), immunoreactivity of 2D8 and 4G3 epitopes correlated negatively and significantly with the triglyceride content (P < 0.01 in both cases), but with neither the size nor the other lipid parameters of LDL particles. Furthermore, changes in the triglyceride content of LDL correlated significantly with changes in apoB immunoreactivity after in vitro treatment with either lipid transfer activity alone (P < 0.01 with 2D8 and 4G3 Mabs) or lipid transfer activity combined with triglyceride hydrolysis (P < 0.01 with 2D8 and 4G3 Mabs). Finally, both the triglyceride content of native LDL and the total triglyceride level in 12 normolipidemic human plasmas correlated negatively and significantly with the expression of 2D8 epitope (P < 0.03 in both cases) and 4G3 epitope (P < 0.02 in both cases). It is concluded that triglycerides constitute a major determinant of the immunoreactivity of 2D8 and 4G3 apoB epitopes in LDL.http://www.bibsonomy.org/bibtex/2acca9a5e11f5de28586667a664f1e859/biblio24biblio242006-07-07T01:10:50+02:00epitope mapping apob <span style="color:#555555;">S. <a href="http://www.bibsonomy.org/author/Negri">Negri</a> and P. <a href="http://www.bibsonomy.org/author/Roma">Roma</a> and R. <a href="http://www.bibsonomy.org/author/Fogliatto">Fogliatto</a> and P. <a href="http://www.bibsonomy.org/author/Uboldi">Uboldi</a> and S. <a href="http://www.bibsonomy.org/author/Marcovina">Marcovina</a> and A. L. <a href="http://www.bibsonomy.org/author/Catapano">Catapano</a> </span><em>Atherosclerosis</em><em>101(1):37--41</em><em>June1993. </em>Fri Jul 07 01:10:50 CEST 2006Institute of Pharmacological Sciences, University of Milano, Italy.AtherosclerosisJune137--41Immunoreactivity of apo B towards monoclonal antibodies that inhibit the LDL-receptor interaction: effects of LDL oxidation.1011993epitope mapping apob We studied the immunochemical stability of the epitopes for six monoclonal antibodies to human apolipoprotein B-100 upon Cu(2+)-mediated (20 microM) oxidation of LDL. The antibodies used in this study, some of which are known to interfere with the interaction of LDL with their cellular receptors, recognize epitopes in the amino terminal region (Mb 19), in the middle part (6B, 2A, 7A, and 9A) and near aa 3500 (Mb 47) of native apo B. All antibodies except one (7A) recognized native and oxidized LDL (OxLDL) equally well; the immunoreactivity of the epitope for Ab 7A was markedly reduced upon LDL oxidation. Since antibodies 2A, 7A, 9A, and Mb 47 inhibit the LDL-receptor interaction and OxLDL poorly interact in vitro with the LDL receptor we conclude that: (1) various epitopes for monoclonal antibodies against native apo B are spared upon LDL oxidation; and (2) the epitopes for antibodies 2A, 9A, and Mb 47 do not define a unique domain of apo B directly involved in the binding of LDL to their receptor.http://www.bibsonomy.org/bibtex/2ede10db90ef6d276b488842c0fa6095f/biblio24biblio242006-07-07T01:10:50+02:00apob mapping epitope <span style="color:#555555;">C. <a href="http://www.bibsonomy.org/author/Fievet">Fievet</a> and C. <a href="http://www.bibsonomy.org/author/Durieux">Durieux</a> and R. <a href="http://www.bibsonomy.org/author/Milne">Milne</a> and T. <a href="http://www.bibsonomy.org/author/Delaunay">Delaunay</a> and G. <a href="http://www.bibsonomy.org/author/Agnani">Agnani</a> and H. <a href="http://www.bibsonomy.org/author/Bazin">Bazin</a> and Y. <a href="http://www.bibsonomy.org/author/Marcel">Marcel</a> and J. C. <a href="http://www.bibsonomy.org/author/Fruchart">Fruchart</a> </span><em>Journal of Lipid Research</em><em>30(7):1015--1024</em><em>July1989. </em>Fri Jul 07 01:10:50 CEST 2006INSERM U 279 et SERLIA, Institut Pasteur, Lille, France.Journal of Lipid ResearchJuly71015--1024Rat monoclonal antibodies to human apolipoprotein B: advantages and applications.301989apob mapping epitope Eight monoclonal antibodies (Mabs) to human serum low density lipoprotein (LDL) were derived from the fusion of spleen cells, from LOU rats immunized with human LDL, and the rat myeloma line IR983F. These Mabs were characterized in terms of isotype, specificity, and affinity. Competitive experiments indicated that the epitopes that were recognized could be grouped into three patterns depending on their apparent affinity for apoB-containing lipoprotein particles such as LDL, very low density lipoproteins (VLDL), or intermediate density lipoproteins (IDL). Six epitopes have been mapped in relation to elements of the sequence of apolipoprotein B-100 (apoB-100) and some have been assigned to the middle part of the median thrombolytic fragment T3, a region not yet well targeted by mouse Mabs. The presence of lipids for the expression of the epitopes was studied and confirmed a lipid dependence for epitopes that are close to the T2/T3 cleavage site. The capacity of binding to the LDL receptor was also tested; among the Mabs we described, one inhibited the uptake and degradation of LDL to HeLa cells receptor. Finally, some antibodies were able to precipitate LDL in gel.http://www.bibsonomy.org/bibtex/2426d09d1aa1b3094042da65c771a8529/biblio24biblio242006-07-07T01:10:50+02:00mapping epitope apob <span style="color:#555555;">E. S. <a href="http://www.bibsonomy.org/author/Krul">Krul</a> and Y. <a href="http://www.bibsonomy.org/author/Kleinman">Kleinman</a> and M. <a href="http://www.bibsonomy.org/author/Kinoshita">Kinoshita</a> and B. <a href="http://www.bibsonomy.org/author/Pfleger">Pfleger</a> and K. <a href="http://www.bibsonomy.org/author/Oida">Oida</a> and A. <a href="http://www.bibsonomy.org/author/Law">Law</a> and J. <a href="http://www.bibsonomy.org/author/Scott">Scott</a> and R. <a href="http://www.bibsonomy.org/author/Pease">Pease</a> and G. <a href="http://www.bibsonomy.org/author/Schonfeld">Schonfeld</a> </span><em>J Lipid Res</em><em>29(7):937--947</em><em>July1988. </em>Fri Jul 07 01:10:50 CEST 2006Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110.J Lipid ResJuly7937--947Regional specificities of monoclonal anti-human apolipoprotein B antibodies.291988mapping epitope apob The usefulness of monoclonal antibodies as probes of protein structure is directly related to knowledge of the structures and locations of the epitopes with which they interact. In this report we provide a detailed map of 13 epitopes on apoB-100 defined by our anti-apoB monoclonal antibodies based on current information on the amino acid sequence of apoB-100. To localize antibody specificities to smaller regions along the linear sequence of the apoB-100 molecule we used a) thrombin- and kallikrein-generated fragments of apoB-100; b) beta-galactosidase- apoB fusion proteins; c) heparin; and d) antibody versus antibody competition experiments. Most of the monoclonal antibodies elicited by immunization with LDL were directed towards epitopes within the first 1279 amino terminal (T4/K2 fragments) or last 1292 carboxyl terminal amino acid residues (T2/K4 fragments) of apoB-100. One epitope localized to the mid-portion of apoB-100 was elicited by immunization with VLDL (D7.2). Saturating amounts of heparin bound to LDL did not inhibit the binding of any of the monoclonal antibodies to their respective epitopes on apoB-100, indicating that none of the antibody determinants is situated close to any of the reported heparin binding sites on LDL apoB. We examined the expression of apoB epitopes on VLDL subfractions and LDL isolated from a normolipidemic donor. The apparent affinities with which the antibodies interacted with their respective epitopes on the VLDL subfractions and LDL uniformly increased as follows: LDL greater than VLDL3 greater than VLDL2 greater than VLDL1, suggesting that each of the major regions of apoB-100 is progressively more exposed as normal VLDL particles become smaller in size and epitopes are most exposed in LDL. Previous experiments utilizing hypertriglyceridemic VLDL subfractions yielded similar results, but the rank order of VLDL subfractions and LDL was not the same for all antibodies tested. Thus, differences in apoB epitope expression on VLDL particles of differing sizes is a general phenomenon, but the expression of apoB epitopes in hypertriglyceridemic VLDL appears to be more heterogeneous than is the case for VLDL from normolipidemic donors.(ABSTRACT TRUNCATED AT 400 WORDS)http://www.bibsonomy.org/bibtex/2224a8336e8cd6eb4bc212b54b6964eb1/biblio24biblio242006-07-07T01:10:50+02:00apob epitope mapping <span style="color:#555555;">E. <a href="http://www.bibsonomy.org/author/Gherardi">Gherardi</a> and A. <a href="http://www.bibsonomy.org/author/Hutchings">Hutchings</a> and G. <a href="http://www.bibsonomy.org/author/Galfre">Galfre</a> and D. E. <a href="http://www.bibsonomy.org/author/Bowyer">Bowyer</a> </span><em>Biochem J</em><em>252(1):237--245</em><em>May1988. </em>Fri Jul 07 01:10:50 CEST 2006Department of Pathology, University of Cambridge, U.K.Biochem JMay1237--245Rat monoclonal antibodies to rabbit and human serum low-density lipoprotein.2521988apob epitope mapping A total of 16 hybrid myeloma clones secreting monoclonal antibodies (McAb) to rabbit or human serum low-density lipoprotein (LDL) were derived from the fusion of spleen cells from LOU or DA rats immunized with rabbit or human LDL and the rat myeloma lines Y3 Ag1.2.3 or YB2/0. Anti-(rabbit LDL) McAb showed limited reactivity with LDL from human, rhesus-monkey, rat and mouse serum. Six out of seven anti-(human LDL) McAb reacted with rhesus-monkey LDL, and only one showed partial cross-reaction with rabbit LDL. Binding-competition experiments indicated that the epitopes recognized by the anti-(rabbit LDL) IgG could be grouped into two major clusters: McAb in the first cluster reacted either with apo-(lipoprotein B-100) (apoB-100) and apo-(lipoprotein B-74) (apoB-74) or with apoB-100 but not with apo-(lipoprotein B-48) (apoB-48), the lower-Mr form of apoB of intestinal origin; the McAb in the second cluster all reacted with apoB-48 in addition to apoB-100 or apoB-100 and apoB-74. The six anti-(human LDL) IgG bound to separate epitopes on LDL. Further data on the epitope specificity of these McAb were obtained by antibody blotting after partial proteolysis of apoB-100 with trypsin or staphylococcal V8 proteinase, and the data confirmed the results obtained with the binding-competition experiments. One McAb to rabbit LDL inhibited the binding of LDL to the fibroblast LDL receptor (50% inhibition at a McAb/LDL molar ratio of 10). A similar result was produced by two other McAb at higher concentrations of antibody.