Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026764 (multiple myeloma)
 36,148 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have characterized a monoclonal isogeneic antiidiotype, IdB5.7, from a BALB/c mouse immunized with the anti-alpha(1----6)dextran C57BL/6 45.21.1. It defined a hapten-inhibitable idiotope expressed on four of the 2 myeloma and 37 hybridoma anti-alpha(1----6)dextrans tested. Sequence comparison of Id+ and Id- anti-alpha(1----6)dextrans suggested that two extra amino acids at VH 100A and 100B and different residues at VH 101 abolish the expression of the idiotope in the Id- anti-alpha(1----6)dextrans. Sequence analysis of the VH of IdB5.7 showed a CDR1 longer than usual and a D segment in CDR3 formed by the fusion of two D minigenes. The IdB5.7 V kappa uses the V kappa 1 germline gene K5.1 with a few substitutions. The D-D fusion in VH CDR3 is a feature which has been reported in several other antiidiotypic antibodies.
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PMID:Specificity and variable region cDNA sequence of an isogeneic monoclonal antiidiotype to an anti-alpha(1----6)dextran. 171 74

Amyloid subunit proteins related to the lambda IV subgroup of immunoglobulin light chains have not been previously reported. We have determined the amino acid sequence of an AL amyloid protein BAK and shown that it has the structure typical of lambda IV light chain proteins. This protein, which was isolated from the spleen of a patient with AL amyloidosis, has 111 residues in the variable domain and also includes the first tryptic peptide of the constant domain for a total of 130 residues. Comparison of the primary structure of this protein with the only other completely characterized lambda IV protein (SH) reveals that they are highly homologous with only one amino acid change in FR1, two changes in FR2, and one change in FR3. The CDR regions also show few changes, with only three in CDR1, one in CDR2, and five in CDR3. To test the hypothesis that the formation of AL amyloid is related to changes in the FR regions which could affect molecular aggregation, the structure of BAK was compared with the myeloma protein SH with respect to the presumed tertiary structure. Only limited amino acid substitution was found in the surface positions that might affect intradimer and interdimer aggregation. These included an isoleucine for leucine change at position 43 and phenylalanine for valine at 45, which may affect intradimer interaction and a change of histidine to asparagine at position 67.
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PMID:Amyloidosis related to a lambda IV immunoglobulin light chain protein. 249 77

The amino-acid sequence Phe-Tyr-Met-Glu is unique to phosphorylcholine (PC)-binding antibodies. It occurs in the first complementarity-determining region (CDR1) of the immunoglobulin heavy chains in 89% of all the anti-PC myeloma and hybridoma proteins but is not present in 490 other immunoglobulin heavy chains, 854 light chains or in 2,260 other unrelated proteins. This unique tetrapeptide therefore seems to be involved in PC binding. Here we compare the effectiveness of Phe-Tyr-Met-Glu and other structurally related peptides in inhibiting the binding of PC to PC-binding proteins McPC603 and HOPC8. We also test a surface-simulation peptide that was constructed to mimic the combining site of McPC603. Our data suggest that all these peptides inhibit the binding of PC to PC-binding proteins non-specifically and we show by computer modelling that the surface-simulation peptide does not duplicate the combining site of McPC603.
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PMID:Inhibition of phosphorylcholine binding to antibodies using synthetic peptides. 380 74

Immunophenotypic studies show the presence of CD10-bearing malignant cells in a small subset of multiple myeloma (MM) patients. We used a sensitive PCR-based technique in order to determine the frequency that MM patients contain a malignant subpopulation which expresses this antigen. The immunoglobulin (Ig) heavy chain variable region (VH) gene sequence expressed by the malignant clone in MM can be used as a tumor specific marker. After determining this sequence in six MM patients, patient specific VH oligonucleotide primers from complementarity determining region (CDR) sequences were generated. Bone marrow mononuclear cells from these patients were incubated with two different anti-CD10 antibodies or isotype identical murine IgG controls. Cells were then sorted by flow cytometry into the 1% brightest cells containing > 99.99% CD10-positive cells and two fractions including the 90 and 10% dimmest staining cells. PCR amplification was performed on DNA from approximately 10(4) cells (0.1 microgram) using patient specific CDR1 and CDR3 primers. Detectable PCR product was obtained in each sorted sample although the intensity of the band was much higher in cells lacking CD10 expression (the 90 and 10% dimmest fractions) than in the CD10-bearing (1% brightest) population. These results imply that there is a small population of CD10-bearing clonal cells in most, if not all patients with MM.
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PMID:A CD10-positive subset of malignant cells is identified in multiple myeloma using PCR with patient-specific immunoglobulin gene primers. 747 88

We have previously demonstrated that the immunoglobulin (Ig) heavy chain variable region (VH) sequences expressed by the malignant clone in multiple myeloma (MM) contain a high degree of somatic mutation without clonal diversity. This sequence can be used to identify all members of the malignant clone in this B cell malignancy. We sequenced the variable regions expressed by patients with MM and generated primers from the complementarity determining region (CDR) sequences specific for each patient's tumor. Using these primers, we performed PCR amplification on highly purified subpopulations of cells separated by expression of CD10, CD34 and CD38. The results of these experiments demonstrate: 1) there is a small fraction of CD10-expressing tumor cells in MM patients, 2) CD34-bearing malignant cells do not exist in MM, and 3) although the vast amount of tumor is in the CD38-expressing cells, a small amount of tumor is in the CD38-negative population. We also used these primers to determine whether pre-class switch (i.e., Cmu-expressing lymphocytes) clonal cells exist in these patients. After PCR amplification with CDR1 and Cmu primers, colony hybridization was performed using both framework 3 (FR3) and CDR3 probes. Out of > 200 FR3-hybridizing colonies, < or = 5 colonies also hybridized with the CDR3 probe. Colonies which hybridized with both these probes were sequenced, and none of these sequences matched even closely the CDR3 expressed by the malignant clone. These results make the existence of a pre-class switch malignant cell unlikely in MM. Overall, these results suggest that the malignant clone in MM derives from a cell late in B lymphocyte development.
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PMID:Multiple myeloma clones are derived from a cell late in B lymphoid development. 753 71

The affinity maturation of antibodies is driven by somatic hypermutation which is localized to specific segments of the coding genes. The information available on this process derives from studies in vivo. With the intention of developing new approaches, we have constructed a fusion gene between a kappa chain and a selectable neomycin resistance gene, neor. The neor gene, which includes the SV40 small t intron and polyadenylation site, but not the upstream elements nor its first 12 amino acids, is an in-frame substitution of the FR2-CDR3 fragment of a rearranged V kappa OX1-J kappa 5 gene. Expression of neor activity is therefore dependent on the upstream immunoglobulin sequence. A stop codon was placed in the CDR1 region so that only mutants survive treatment with geneticin sulphate (G418). The effectiveness of the system was tested by transfecting the NS0 myeloma cell line and isolating spontaneous mutants. Neomycin-resistant clones arose at an estimated rate of 1 x 10(-8)/cell division, and over 90% were authentic structural mutants. Unlike the somatic hypermutations, the majority arose by in-frame deletions including the stop codon, although up to 30% involved a point mutation. The reporter gene was then modified by substituting all the sequences downstream of the J kappa 5 with others known to be required for full hypermutation in vivo. Different cell lines were transfected and G418-resistant clones analyzed. No significant increase in the rate of reversion or in the generation of point mutations versus deletions was detected, even using conditioned culture medium. In the presence of azacytidine however, a mutant involving multiple events (single base addition and deletion plus two point mutations) was detected. The reporter gene system therefore seems suitable to test culture conditions and modifications of the host cells aimed at the derivation of an in vitro assay of somatic hypermutation.
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PMID:A reporter gene to analyse the hypermutation of immunoglobulin genes. 778 11

We determined the specificity and sequence of immunoglobulin molecules synthesized by monoclonal B cells from a patient with chronic lymphocytic leukaemia (CLL) who presented with a number of clinical and biological autoimmune symptoms. Heterohybrids obtained by fusion of CLL cells with the mouse X63-Ag 8.653 myeloma produced IgM lambda MoAbs directed to the cardiolipin/beta 2 glycoprotein I (beta 2GPI) complex and ssDNA. They were devoid of polyreactivity. Nucleotide sequence analysis of the variable domain of the mu chain indicated the utilization of the VH4 71.2 gene or one allotypic variant, DXP4 and JH3 segments. The lambda light chain used the single gene from the V lambda 8 subfamily, J lambda 3 and C lambda 3 genes. The VH gene displayed 11 nucleotide changes in comparison with its putative germline counterpart. However, these nucleotide changes correspond to variations observed in other published VH4 sequences, suggesting gene polymorphism rather than somatic mutation. DXP4 and JH3 were also in germline configuration. The VL gene exhibited a single replacement mutation in CDR1. These data suggest that the monoclonal CLL B cells in this patient retained VH and VL genes in germline configuration although they secreted a pathogenic anti-cardiolipin antibody associated with clinical symptoms, vasculitis and thrombosis, which may be provoked by antibodies to the phospholipid/beta 2GPI complex.
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PMID:Characterization of a human monoclonal autoantibody directed to cardiolipin/beta 2 glycoprotein I produced by chronic lymphocytic leukaemia B cells. 822 31

A hybridoma producing a polyspecific human monoclonal IgM antibody (named CB03) has been derived from a fusion of mouse myeloma cells with human spleen lymphocytes obtained from an autoimmune patient suffering from chronic idiopathic thrombocytopenia. The antibody was found to be encoded by somatically mutated VHI and VlambdaIII genes. To study the input of mutated complementarity regions (CDRs) into antibody specificity, the antigen binding features of the purified complete IgM antibody were compared with (i) a Fab fragment by hot tryptic digestion and (ii) recombinant monovalent fragments expressed in E. coli. In detail, vectors were constructed encoding for (i) rFab03 and single chain Fv03 fragments containing the VH and VL genes connected by a linker sequence, (ii) scFc1.1. fragments containing the VH germline equivalent and the CB03 wild-type CDR3 region, and (iii) scFv fragments containing the CDR1 and CDR2 in germline configuration and the CDR3 expressed in the CB253 human fetal B cell hybridoma producing a polyspecific IgM antibody. The expression vectors contained at the 3' end either a (His)6 motif allowing purification on Ni(2+)-agarose or a c-myc tag for specifically detecting the expression products by a murine monoclonal antibody. Western blotting and ELISA analyses of the expression products indicate: (i) recombinant Fab fragments were found in the bacterial periplasm in extremely low amounts (1-10 micrograms from 1 litre bacterial culture), (ii) scFv fragments were obtained in suitable amounts from bacterial periplasm (800-1000 micrograms/l), (iii) the monovalent recombinant fragments as well as the Fab obtained by tryptic digestion reflected the polyspecific antigen binding features of the complete IgM antibody, but did bind to the antigens with much lower affinity, and (iv) the CDR3 was found to be of critical importance for the antigen binding pattern of this particular IgM. We discuss the expression of recombinant scFv fragments in E. coli as a suitable method in studying the role of the somatic mutation in autoantibody generation.
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PMID:Expression of monovalent fragments derived from a human IgM autoantibody in E. coli. The input of the somatically mutated CDR1/CDR2 and of the CDR3 into antigen binding specificity. 852 57

IgG myeloma proteins (MPs) produced by monoclonal plasma cells derived from B2 lymphocytes have been reported to bind to various autoantigens but the binding generally has been of low affinity. Moreover, T cells from some multiple myeloma patients can respond specifically to idiotypes of their own paraproteins. We analyzed the capacity of more than 20 human IgG MP to bind, a recombinant single-chain molecule containing complete V beta 8.1 and V alpha 1 structures, sets of synthetic peptide epitopes corresponding to a complete TCR beta chain, and a set of CDR1 epitopes corresponding to 24 human V beta gene products, and intact monoclonal T cells. Two of 20 MPs bound strongly to the recombinant TCR. Five of the same set, including these, bound to a synthetic epitope corresponding to the CDR1 segment. On a mass basis, the binding was approximately 1000-fold greater than that of pooled polyclonal IgG. The binding activity was confined to the Fab fragment and was specifically inhibitable by appropriate peptide determinants. Spectrotypic analysis using a set of CDR1 epitopes indicated that individual proteins showed characteristic binding patterns ranging from highly specific to relatively promiscuous. Highly reactive MPs also bound to TCR on intact cells in immunocytofluorescence by flow cytometry. These results are consistent with the relatively frequent occurrence of autoantibodies to TCR determinants and indicate that MPs can be derived from this autoantibody subset.
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PMID:Binding of human IgG myeloma proteins to autologous T-cell receptor determinants. 941 36

Antibody light chains of the kappa subgroup are the predominant light chain component in human immune responses and are used almost exclusively in the antibody repertoire of mice. Human kappa light chains comprise four subgroups. To date, all crystallographic studies of human kappa light chains were carried out on proteins of the kappaI subgroup. The light chain produced by multiple myeloma patient Len. was of the kappaIV subgroup, it differed by only one residue from the germ-line gene encoded protein. The variable domain fragment of the light chain was crystallized from ammonium sulfate in space group C222(1). The crystal structure was determined by molecular replacement and refined at 1.95 A resolution to an R-factor of 0.15. Protein Len has six additional residues in its CDR1 segment compared to the kappaI proteins previously characterized. The kappaIV variable domain, Len, differs in only 23 of 113 residues from murine kappa light chain McPC603. The RMS deviation upon superimposing their alpha-carbons was 0.69 A. The CDR1 segment of the human and murine variable domains have the same length and conformation although their amino acid sequences differ in 5 out of 17 residues. Structural features were identified that could account for the significantly higher stability of the human kappaIV protein relative to its murine counterpart. This human kappaIV light chain structure is the closest human homolog to a murine light chain and can be expected to facilitate detailed structural comparisons necessary for effective humanization of murine antibodies.
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PMID:Variable domain structure of kappaIV human light chain Len: high homology to the murine light chain McPC603. 968 71


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