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)

Secretory immunoglobulin A (IgA) antibodies directed against cholera toxin (CT) are thought to be important in resistance to oral challenge with virulent Vibrio cholerae, although alternative mechanisms for protection of intestinal epithelia against CT-induced fluid secretion have been proposed. The ability of anti-CT IgA to block the effects of CT on human enterocytes has not been directly tested because of the lack of a well-defined in vitro intestinal epithelial cell system to directly measure toxin action and the limited availability of purified anti-CT IgA antibodies. We have generated hybridomas that produce monoclonal IgA and IgG antibodies directed against CT by fusion of Peyer's patch cells with mouse myeloma cells after oral-systemic immunization of mice with CT and CT B-subunit protein. All of the anti-CT antibodies recognized the B subunit. Three clones (designated anti-CTB IgA-1, IgA-2, and IgA-3) which produced IgA antibodies in dimeric and polymeric forms were selected. Checkerboard immunoblotting demonstrated that IgA-1 recognized an epitope distinct from that recognized by IgA-2 and IgA-3 and that none of the antibodies were directed against the binding site of GM1, the intestinal cell membrane toxin receptor. The protective capacity of these IgAs was tested in vitro with human T84 colon carcinoma cells grown on permeable supports as confluent monolayers of polarized enterocytes. When each anti-CTB IgA was mixed with 10 nM CT and applied to the apical surfaces of T84 cell monolayers, all three IgAs blocked CT-induced Cl- secretion in a dose-dependent manner and completely inhibited binding of rhodamine-labelled CT to apical cell membranes. Thus, monoclonal anti-CTB IgA antibodies are sufficient to protect human enterocytes in vitro against CT binding and action.
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PMID:Monoclonal immunoglobulin A antibodies directed against cholera toxin prevent the toxin-induced chloride secretory response and block toxin binding to intestinal epithelial cells in vitro. 769 98

Carcinoembryonic antigen (CEA) has been shown to be one of the best markers for in vivo tumor targeting of radiolabeled antibodies, despite the fact that it is localized predominantly at the apical side of human colon carcinoma cells within the fairly closed pseudolumen structures formed by these tumors. Due to this particular histological localization, a large proportion of the CEA molecules may remain inaccessible to the intravenously injected radiolabeled anti-CEA antibodies of IgG isotype, which are widely used in the clinic. In order to improve targeting, we made a recombinant dimeric IgA, which should have the capacity to translocate from the basolateral to the apical side of the pseudolumen formed by colon carcinoma cells after binding to the polyIg receptor (pIgR). A genomic chimeric mouse-human IgA2 construct was made using one of our most specific anti-CEA hybridomas, CE-25. The chimeric IgA (chIgA) was expressed in the Sp2/0 myeloma cell line. The secreted recombinant antibody was found to consist mostly of a dimeric form of IgA with a molecular weight of about 350 kDa. The dimeric chIgA was shown to translocate efficiently in vitro across a monolayer of epithelial cells expressing the pIgR and to retain full CEA binding activity.
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PMID:Dimeric recombinant IgA directed against carcino-embryonic antigen, a novel tool for carcinoma localization. 799 43

Protein Arp, the IgA-binding protein of the group A Streptococcus, has affinity for the Fc-part of IgA. The binding between protein Arp and several different molecular forms of human IgA was characterized. It was found that protein Arp bound with higher affinity to uncomplexed forms of IgA than to complexed forms (secretory IgA, alpha 1-antitrypsin-IgA and alpha 1-microglobulin-IgA). Thus, the affinity constant was 2.0-5.9 x 10(8) M-1 for the binding to monomeric, dimeric, trimeric, and quadrimeric IgA, and 4.5-5.0 x 10(7) M-1 for binding to the complexed forms. Among the uncomplexed IgA-molecules, the affinity constant was in the same range for J chain-containing forms (dimeric, trimeric and quadrimeric IgA) as for forms without J chain (monomeric and a particular quadrimeric IgA devoid of J chain). Western blotting demonstrated that protein Arp bound exclusively to the alpha-chain of all IgA-forms. Several lines of evidence pointed to a localization of the binding site to the C alpha 3-domain. First, protein Arp did not bind to three N-terminal alpha-chain fragments which lacked a region corresponding to the C alpha 3-domain, including that form a four-chain myeloma IgA, naturally occurring in plasma. Second, the binding to dimeric and tri/quadrimeric IgA was partially blocked by an added secretory component, which has been suggested to bind to the C alpha 2- and C alpha 3-domains of the alpha-chain. Finally, alpha 1-antitrypsin and alpha 1-microglobulin, in the weakly binding IgA-complexes, have been shown to be linked to the C alpha 3-domain via the penultimate amino acid residue of the alpha-chain peptide, supporting the hypothesis of a localization of the binding site of protein Arp to the C alpha 3-domain.
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PMID:Interaction between streptococcal protein Arp and different molecular forms of human immunoglobulin A. 815 42

We describe construction of a single gene encoding a single-chain immunoglobulin-like molecule. This single-gene approach circumvents inefficiencies inherent in delivering two genes into a mammalian cell and in the assembly of a functional immunoglobulin molecule. It would also facilitate ex vivo transfection of cells for gene-therapy protocols. SP2/0 murine myeloma cells transfected with the single gene SG delta CLCH1 expressed a single-chain protein, SC delta CLCH1, comprising approximately 60 kDa of the anti-carcinoma monoclonal antibody (mAb) CC49. The single-chain protein consisted of the heavy- and light-chain variable (VH and VL) domains of the mAb covalently joined through a short linker peptide, while the carboxyl end of the VL domain was linked to the amino terminus of the human gamma 1 Fc region through the hinge region. The single-chain protein assembled into a dimeric molecule, termed SCA delta CLCH1, of approximately 120 kDa and was secreted into the tissue culture fluid. SDS/PAGE analysis of the secreted immunoglobulin purified by protein G affinity chromatography confirmed the size of the molecule. The native mAb CC49 and SCA delta CLCH1 of CC49 showed similar binding to the tumor-associated glycoprotein TAG-72, and the chimeric mAb CC49 and SCA delta CLCH1 showed similar cytotoxic activity. This single-gene construct approach provides a way of generating an immunoglobulin-like molecule which retains the specificity, binding properties, and cytolytic activity of the chimeric mAb CC49. The immunoglobulin-like molecule SCA delta CLCH1 is potentially a therapeutic and diagnostic reagent against a range of human carcinomas.
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PMID:Secretion of a single-gene-encoded immunoglobulin from myeloma cells. 836 54

Disulfide bonds are a major force in stabilizing the three-dimensional structure of immunoglobulins. To determine the pattern of interchain disulfide bonding between the four H chains, four L chains and single J chain of rat dimeric IgA (dIgA), we analyzed dIgA from the LO DNP-64 hybridoma by diagonal SDS-PAGE. Bands corresponding to one, two, three and four H chains, one and two L chains and the free J chain were observed under non-reducing conditions, suggesting that the interchain disulfide bonds in rat dIgA are unstable under denaturing conditions. Similar patterns of disulfide bonding were observed in three other hybridoma or myeloma dIgAs from LOU/CN rats. In contrast, when dIgA pretreated with iodoacetamide (IA) was analyzed by the same technique, only bands corresponding to four H chains, one and two L chains and the free J chain were observed, suggesting that blocking free sulfhydryl groups stabilizes the inter-H chain disulfide bonds. Reaction of dimeric LO DNP-64 dIgA with 5,5'-dithiobis-(2-nitrobenzoic acid) or with 14C-IA demonstrated that this dIgA contains an average of 4 moles of free sulfhydryl groups per mole of protein under non-denaturing conditions and 9 moles of free sulfhydryl groups under denaturing conditions. Taken together, the results suggest that interchain disulfide bonds in rat dIgA are unstable, presumably due to the influence of nearby free sulfhydryl groups, and that non-covalent forces are critical for stabilizing the dIgA complex. The results also indicate that J chain is entirely non-covalently associated with the H chains, an apparently unique feature of rat dIgA. A model for interchain disulfide bonding in rat dIgA is proposed.
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PMID:Unstable inter-H chain disulfide bonding and non-covalently associated J chain in rat dimeric IgA. 1269 23

Oral administration of rabbit secretory IgA (sIgA) to adult BALB/c mice induced IgA+, IgM+, and IgG+ lymphoblasts in the Peyer's patches, whose fusion with myeloma cells resulted in hybridomas producing IgA, IgM, and IgG1 antibodies to the secretory component (SC). This suggests that SC could serve as a vector to target protective epitopes into mucosal lymphoid tissue and elicit an immune response. We tested this concept by inserting a Shigella flexneri invasin B epitope into SC, which, following reassociation with IgA, was delivered orally to mice. To identify potential insertion sites at the surface of SC, we constructed a molecular model of the first and second Ig-like domains of rabbit SC. A surface epitope recognized by an SC-specific antibody was mapped to the loop connecting the E and F beta strands of domain I. This 8-amino acid sequence was replaced by a 9-amino acid linear epitope from S. flexneri invasin B. We found that cellular trafficking of recombinant SC produced in mammalian CV-1 cells was drastically altered and resulted in a 50-fold lower rate of secretion. However, purification of chimeric SC could be achieved by Ni2+-chelate affinity chromatoraphy. Both wild-type and chimeric SC bound to dimeric IgA, but not to monomeric IgA. Reconstituted sIgA carrying the invasin B epitope within the SC moiety triggers the appearance of seric and salivary invasin B-specific antibodies. Thus, neo-antigenized sIgA can serve as a mucosal vaccine delivery system inducing systemic and mucosal immune responses.
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PMID:A pathogen-specific epitope inserted into recombinant secretory immunoglobulin A is immunogenic by the oral route. 896 37

Insulin-like growth factors (IGF) I and II are potent mitogens for a variety of cancer cells. The proliferative and anti-apoptotic actions of IGF are mediated by the IGF-I receptor (IGF-IR), to which both IGF-I and IGF-II bind with high affinity. To investigate the mitogenic and anti-apoptotic activities of IGF-IR and to achieve better inhibition of IGF-IR function, single-chain antibodies against human IGF-IR (alphaIGF-IR scFvs) were constructed and expressed. IgG cDNA encoding variable regions of light and heavy chains (VL and VH) from mouse IgG were cloned from a hybridoma producing the 1H7 alphaIGF-IR monoclonal antibody [Li et al., Biochem Biophys Res Commun 196: 92-98 (1993)]. The splice-overlap extension polymerase chain reaction was used to assemble a gene encoding the alphaIGF-IR scFv, including the N-terminal signal peptide, VL, linker peptide, VH, and C-terminal DYKD tag. Two types of soluble alphaIGF-IR scFvs, a prototype alphaIGF-IR scFv and its alternative type alphaIGF-IR scFv-Fc, were constructed and expressed in murine myeloma cells. alphaIGF-IR scFv-Fc, containing the human IgG1 Fc domain, was stably expressed in NS0 myeloma cells, using a glutamine synthase selection system, and purified from the conditioned medium of stable clones by protein-A--agarose chromatography. Levels of alphaIGF-IR scFv-Fc expression ranged from 40 mg/l to 100 mg/l conditioned medium. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis analysis under reducing and nonreducing conditions indicated that alphaIGF-IR scFv-Fc is a dimeric antibody. alphaIGF-IR scFv-Fc retained general characteristics of the parental 1H7 monoclonal antibody except that its binding affinity for IGF-IR was estimated to be approximately 10(8) M(-1), which was one-order of magnitude lower than that of 1H7 monoclonal antibody. Injection of alphaIGF-IR scFv-Fc (500 microg/mouse, twice a week) significantly suppressed MCF-7 tumor growth in athymic mice. These results suggest that the alphaIGF-IR scFv-Fc is a first-generation recombinant alphaIGF-IR for the potential development of future alphaIGF-IR therapeutics.
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PMID:Single-chain antibodies against human insulin-like growth factor I receptor: expression, purification, and effect on tumor growth. 1094 7

We report here a lupus anticoagulant (LA)-like activity observed in a 45-year-old man with Bence-Jones protein (BJP) lambda-type multiple myeloma. This patient showed no clinical symptoms of thrombosis or bleeding diathesis. Laboratory examination on admission showed mild anemia, prolongation of activated partial thromboplastin time (APTT) (APTT, 56.2 seconds; control, 29.1 seconds), normal prothrombin time, normal thrombin time, and massive proteinuria (2.3 g/d). The mix test with normal plasma showed the presence of circulating anticoagulant. Based on the assumption that the lambda-type BJP may have been responsible for the prolongation of APTT, we purified the BJP from the patient's urine using column works. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting showed that the purified protein was a 48-kd homodimer of immunoglobulin lambda-chains. Addition of the purified dimeric lambda-type BJP to the normal plasma prolonged both APTT and dilute Russell's viper venom time (DRVVT) in a dose-dependent manner, and the negatively charged phospholipid-dependent prothrombinase activity was significantly inhibited in the presence of this protein. Furthermore, both the prolongation of DRVVT and the inhibition of the prothrombinase activity were almost completely abrogated under the condition of high ionic strength. These findings collectively suggest that the dimeric lambda-type BJP showed LA-like activity via the mechanism of ionic charge.
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PMID:Lupus anticoagulant-like activity observed in a dimeric lambda protein produced by myeloma cells. 1150 69

Nuclear factor-kappaB (NF-kappaB) is a collective term that refers to a small class of dimeric transcription factors for a number of genes, including growth factors, angiogenesis modulators, cell-adhesion molecules, and antiapoptotic factors. Although most NF-kappaB proteins promote transcription, some act as inactivating or repressive complexes. The most common p50-RelA (p65) dimer known "specifically" as NF-kappaB, is relatively abundant, controls the expression of numerous genes, and exists as an inactive cytoplasmic complex bound to inhibitory proteins of the NF-kappaB inhibitor (IkappaB) family. The inactive NF-kappaB-IkappaB complex is activated by a variety of stimuli, including proinflammatory cytokines, mitogens, growth factors, and stress-inducing agents. The release of NF-kappaB facilitates its translocation to the nucleus, where it promotes cell survival by initiating the transcription of genes encoding stress-response enzymes, cell-adhesion molecules, proinflammatory cytokines, and antiapoptotic proteins. Constitutive activation of NF-kappaB in the nucleus is observed in some hematologic disorders. With the recent approval of bortezomib for patients with advanced multiple myeloma, NF-kappaB modulation is likely to be a therapeutic endeavor of increasing interest in coming years.
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PMID:Nuclear factor-kappaB modulation as a therapeutic approach in hematologic malignancies. 1507 43

We established an IgA monoclonal antibody (mAb) against Shiga toxin 1 B subunits (Stx1B) from mouse nasal-associated lymphoid tissues (NALT) of BALB/c mice. We have developed an improved protocol in which cross-linked Stx1B is intranasally administered together with cholera toxin. Surface IgA-positive NALT lymphocytes from mice immunized in this manner were enriched and then fused with mouse myeloma cells to produce hybridoma cells. Hybridoma culture supernatants were examined to see if they contain IgA against Stx1B and if they can inhibit carbohydrate recognition by Stx1B. For the latter purpose, we prepared carbohydrate ligands in which globotriose is present on the poly-lysine backbone. The established IgA mAb exhibited saturable and dose-dependent binding to the immobilized Stx1B. Inversely, the binding of the carbohydrate ligands to the immobilized Stx1B was inhibited by the mAb pretreatment. Immunoblotting and SDS-PAGE analysis revealed dimeric IgA. The IgA mAb inhibited the binding of digoxigenin-conjugated Stx1B to natural ligands displayed on a Burkitt's lymphoma cell line, Ramos. These results suggested that surface IgA-positive B cells in the inductive sites of the mucosal immune system in the upper respiratory tract are a potent source for producing IgA mAb against protein antigens with weak immunogenicity such as Stx1B.
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PMID:Production of IgA monoclonal antibody against Shiga toxin binding subunits employing nasal-associated lymphoid tissue. 1599 15


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