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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Investigations performed in a patient with myeloma, hyperlipidemia, and xanthomatosis demonstrated the antilipoprotein activity of the monoclonal IgA directed against an antigenic site--called Ra.--different from those previously described. A complex IgA beta-lipoprotein has been firstly characterized. After isolation and purification of the IgA, it has been shown that the association between IgA and lipoprotein was immunologically mediated. The antibody is an IgA lambda bound via its Fab portion and in fixed combining ratio to an antigenic determinant shared only by LDL and VLDL of humans and some other mammalians to the exclusion of any other serum proteins. The results obtained with passive hemagglutination and inhibition of hemagglutination suggest that the antigenic site Ra. is not located on apoprotein B (major proteic moiety of LDL and VLDL), since the antigenic determinants of apolipoproteins are different in humans and in animals and since IgA Ra. fails to react with apolipoprotein B obtained by delipidation of LDL. On the other hand, the lack of reaction between IgA Ra. and HDL suggests that the antigenic determinant is not only present on the lipid hapten such as in the case of PG and AS determinants which are located on VLDL, LDL, and HDL from humans and animals. So the antigenic determinant revealed by IgA Ra. seems to be different from those previously described.
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PMID:[Monoclonal myelomatous IgA with antilipoprotein antibody activity of Ra specificity (author's transl)]. 51 6

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.
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PMID:Rat monoclonal antibodies to human apolipoprotein B: advantages and applications. 247 82

An antibodylike paraprotein has been isolated from a patient with multiple myeloma and autoimmune hyperlipoproteinemia. The paraprotein bound to apolipoprotein B (apo B)-containing lipoproteins that formed macromolecular aggregates, and globules thought to be aggregated complexes of lipoproteins and reactive immunoglobulins were observed circulating within the retinal blood vessels of this patient. This binding specificity permitted purification of the paraprotein from both the agglutinated immune complexes and from the plasma. The protein is an IgA, kappa-immunoglobulin which exists primarily in a polymeric state. Capillary immunoprecipitation demonstrated reactivity with very low density lipoproteins (VLDL) and low density proteins (LDL), but not with high density lipoproteins (HDL). Delipidated apo B and apo E, but not apo A or apo C, formed precipitates with this immunoglobulin. In using a radioimmunoassay format, the affinity of the immunoglobulin was greatest for VLDL and decreases sequentially for intermediate density lipoproteins and LDL. No binding occurred with a dispersion of LDL lipids or with HDL. Deglycosylation did not change the binding to LDL. The apolipoproteins B and E bound with similar affinity, but no binding occurred with apo A-I or apo A-II. Weak binding appeared to occur with apo C. This paraprotein immunoprecipitated apo B-containing lipoproteins from all classes of vertebrates tested. Displacement of the lipids of LDL by Triton X-100 resulted in the formation of an apo B-Triton complex which, however, did not bind to the immunoglobulin; apparently the binding site on apo B was lost. Upon enzymatic digestion with the IgA-specific protease from Streptococcus sanguis the immunoglobulin was cleaved into Fc and Fab fragments, and the binding of LDL occurred only with the latter, consistent with the behavior of an immunoglobulin. The immunoreactivity of this paraprotein with apo B and apo E raises the interesting possibility that it may be binding to a site on these apolipoproteins which is reactive with the apo B, E receptor of the plasma membrane, a site which is conserved throughout the vertebrate phylum.
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PMID:Immune complex hyperlipidemia induced by an apolipoprotein-reactive immunoglobulin A paraprotein from a patient with multiple myeloma. Characterization of this immunoglobulin. 316 Jul 25

A middle-aged female presented with diffuse planar xanthomas, associated with normal plasma lipids and a severe crescendo angina. Hematological testing disclosed the presence of a cryoglobulin binding to apolipoprotein B. The patient died after a short and dramatic clinical course. At autopsy, a markedly thickened aorta with diffuse atheromatous lesions of the major peripheral arteries were observed. Intracytoplasmic filaments (50-100 A), comparable to those described in amyloid deposits, were also detected. Endothelial cells were filled with lipid-containing vacuoles without extracellular lipid deposits. The reported case indicates that benign gammopathies against 'atherogenic' lipoprotein components, without clinical myeloma, may result in the development of severe arterial lesions.
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PMID:Antiapolipoprotein B cryoglobulinemia associated with normal plasma lipids and severe atherosclerosis. 360 88

Studies were undertaken to determine the applicability and effectiveness of a new immunoadsorbent, constituted of cellulose hollow fibres chemically modified (BrCN) to link selected proteins. The method has been assayed on a simple model of antibody elimination: myeloma IgG or BSA as antigens were covalently linked to cellulose; such an immunoadsorbent can selectively and efficiently deplete circulating antibodies in vitro and ex vivo (on immunized dogs) from whole blood, without releasing linked protein into the hosts' circulation. The original approach of using this method to remove antibodies has been extended to specifically remove antigens (for this purpose, antibodies were conjugated to cellulose), in order to investigate an immunoadsorption therapy in familial hypercholesterolemia, characterized by a plasmatic overload of low-density-lipoproteins (LDL), of which apolipoprotein B is the major protein. After covalent linkage of isolated anti-apolipoprotein B antibodies to cellulose, human plasma LDL levels were effectively and specifically reduced by this procedure.
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PMID:Suitable hollow fibre immunobioreactors for specific ex vivo removal of antibodies and antigens from plasma. 390 96

Spleen cells obtained from mice immunized with human plasma low-density lipoproteins (LDL) were fused with mouse myeloma cells. The resulting hybridoma cells secreting immunoglobulin specific for LDL were screened and scored by radioimmunoassay and cloned by multiple limiting dilutions. Immunochemical properties of the monoclonal antibodies were compared with convential mouse serum antibodies. It was found that conventional antibodies precipitated LDL and bound more than 95% of 125I-labeled LDL and the maximal binding was independent of temperature. The monoclonal antibodies were incapable of precipitating LDL and bound a maximum of only 20% of the total 125I-labeled LDL. The maximal binding between monoclonal antibodies and LDL was extremely temperature-dependent. An optimal degree of binding was observed at 4 degrees C, whereas binding at 37 degrees C was only 30% of that achieved at 4 degrees C. Although the binding at 37 degrees C was low, the maximal binding could be re-established following a subsequent incubation at 4 degrees C, suggesting that the antigenic structure of LDL is reversibly modulated at temperatures between 4 and 37 degrees C. Since the orientation of apolipoprotein B in LDL is known to be dynamic at different temperatures, this result suggests that monoclonal antibodies, but not conventional antibodies, are capable of detecting subtle conformational changes in LDL. In addition, we have determined the binding affinity of LDL to monoclonal antibodies and to conventional antibodies. Only monoclonal antibodies showed a linear Scatchard plot, suggesting that the binding was to a single site with a single affinity. The monoclonal antibodies also possessed high specificity and failed to react with porcine LDL, while serum antibodies could recognize both human and porcine LDL.
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PMID:Immunochemical properties of human low density lipoproteins as explored by monoclonal antibodies. Binding characteristics distinct from those of conventional serum antibodies. 618 54

Nonenzymatic glycation of apolipoprotein B (apo B) is a post-secretory modification of low density lipoprotein (LDL) that affects its atherogenic potential and is implicated in the accelerated atherosclerosis associated with diabetes. To facilitate assessment of apo B glycation, we produced hybridomas secreting monoclonal antibodies specific for glycated apo B. SP 2/0 myeloma cells were fused with spleen cells from BALB/c mice immunized with purified apo B glycated non-reductively in vitro. Specificity of monoclonal antibodies secreted by the cloned cell line designated ES12 was demonstrated by immunoblotting and by direct ELISA, wherein the antibodies reacted with glycated epitopes residing in LDL but not in other plasma proteins, and did not react with nonglycated apo B or nonglycated LDL. Immunoblotting of human plasma with ES12 monoclonal antibody yielded an approx. 180,000 molecular weight component showing co-identity with apo B, indicating site specificity for glycated epitopes residing in apo B of the LDL complex and absence of reactivity with other nonenzymatically glycated plasma proteins. This reactivity of ES12 with the physiologic form of glycated apo B that occurs in vivo differs from properties of other antibodies raised against glycated lipoproteins, which recognized glycated residues only after reductive conversion to glucitol-lysine and which do not discriminate between different glycated proteins. In a competitive ELISA, mean concentration of glycated LDL, measured as apo B equivalents, in eight separate plasma samples was 19.7 +/- 1.9 micrograms/ml, representing 3.5 +/- 0.3% of total apo B. The ES12 monoclonal antibody allows specific determination of plasma glycated LDL concentrations, which may have diagnostic and pathogenetic importance.
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PMID:Immunologic detection and measurement of glycated apolipoprotein B with site specific monoclonal antibodies. 850 55

To gain insight into multiple myeloma (MM) tumorigenesis, we analyzed the mutational signatures in 874 whole-exome and 850 whole-genome data from the CoMMpass Study. We identified that coding and non-coding regions are differentially dominated by distinct single-nucleotide variant (SNV) mutational signatures, as well as five de novo structural rearrangement signatures. Mutational signatures reflective of different principle mutational processes-aging, defective DNA repair, and apolipoprotein B editing complex (APOBEC)/activation-induced deaminase activity-characterize MM. These mutational signatures show evidence of subgroup specificity-APOBEC-attributed signatures associated with MAF translocation t(14;16) and t(14;20) MM; potentially DNA repair deficiency with t(11;14) and t(4;14); and aging with hyperdiploidy. Mutational signatures beyond that associated with APOBEC are independent of established prognostic markers and appear to have relevance to predicting high-risk MM.
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PMID:Mutational processes contributing to the development of multiple myeloma. 3138 87

The evolution and progression of multiple myeloma and its precursors over time is poorly understood. Here, we investigate the landscape and timing of mutational processes shaping multiple myeloma evolution in a large cohort of 89 whole genomes and 973 exomes. We identify eight processes, including a mutational signature caused by exposure to melphalan. Reconstructing the chronological activity of each mutational signature, we estimate that the initial transformation of a germinal center B-cell usually occurred during the first 2nd-3rd decades of life. We define four main patterns of activation-induced deaminase (AID) and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC) mutagenesis over time, including a subset of patients with evidence of prolonged AID activity during the pre-malignant phase, indicating antigen-responsiveness and germinal center reentry. Our findings provide a framework to study the etiology of multiple myeloma and explore strategies for prevention and early detection.
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PMID:Timing the initiation of multiple myeloma. 3231 34