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)

Dopamine inhibits prolactin release from pituitary cells and seems to affect the release of several other hormones as well. We report here that dopamine may have similar effects on human B lymphoma cells leading to inhibition of production or release of endogenous factors required for cell viability and proliferation. Thus, addition of dopamine to serum-free cultures of Burkitt lymphoma cells (Raji, Namalwa, Daudi and Jijoye) resulted in rapid and extensive cell death while a myeloma cell line, SKO, appeared to be refractory to this treatment. The addition of FCS or supernatant from serum-free cultures of Raji or T24 bladder carcinoma cells could, to a variable degree, counteract the effect of dopamine, suggesting that dopamine acts by inhibiting the production of essential autocrine factors. When two of the hormones known to be under dopamine control, i.e. prolactin (PRL) and thyrotropin (TSH), were tested, they were able to prevent dopamine-induced cell death if combined with heparin. We further observed that the reducing agent 2-mercaptoethanol (2-ME), which is known to inhibit the binding of TSH to its receptor, displayed similar effects to those of dopamine and was strongly inhibitory for Burkitt lymphoma but not for myeloma cells. As expected from its blocking activity at the receptor level, the effect of 2-ME could not be reversed by adding exogenous factors. Contrary to its effect on B lymphoma cells, 2-ME is essential for growth of the murine T-cell lymphoma line CTLL. However, we show here that dopamine can fully compensate for 2-ME, suggesting that TSH or another factor under dopamine control is intimately involved in the regulation of T-cell growth. This study lends further support to the notion of an active interplay between the neuroendocrine and immune systems and emphasizes PRL and TSH as important regulators of lymphoid cell function. It also shows that these hormones may contribute to the autonomous growth pattern of B lymphoma cells and suggests a potential role for dopamine in the treatment of B-cell tumours.
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PMID:Dopamine-induced lymphoma cell death by inhibition of hormone release. 141 1

The glycoprotein hormones CG, LH, FSH, and TSH are composed of two noncovalently linked subunits, alpha and beta. The beta-subunit confers hormone specificity, while the alpha-subunit is homologous within a species. To help in determining the antigenic structure of the common alpha-subunit, six monoclonal antibodies (mAbs) to the free or heterodimeric alpha-subunit of human (h) gonadotropic hormones have been prepared and, along with two previously isolated mAbs, have been characterized for binding specificity to alpha- and beta-subunits and the human glycoprotein hormones, CG, LH, FSH, and TSH. Each mAb was derived from hybidomas of FO myeloma cells fused with spleen cells from mice immunized with free alpha-subunit, hCG or hFSH. mAbs A101, A102, and E512 were specific for the alpha-subunit but showed the highest affinity for the intact hormone; K2.18, K94.6, E501, E502, and E511 were specific for free alpha. All of the antibodies inhibited binding of 125I-hCG to luteal membrane receptor, and 125I-labeled mAbs did not recognize hCG/receptor complex. Characterization by two-site binding assays using alpha, hCG, or hFSH as antigen revealed that all the mAbs bind to unique sites on alpha which may be overlapping, and which are modified in the intact hormone. The antigenic sites for mAbs E502, E511, and K2.18 are at least partially linear because they bind to reduced, carboxymethylated alpha.
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PMID:The antigenic structure of the human glycoprotein hormone alpha-subunit. I. Characterization of anti-alpha monoclonal antibodies. 170 Nov 33

Using beta and alpha subunits of bullfrog follitropin (FSH) III (pI 6.2), which were highly purified by HPLC, we generated three monoclonal antibodies (MCAs) to FSH beta subunit (FSH beta) and six to FSH alpha subunit (FSH alpha). They were produced by hybridomas derived from the myeloma X63.Ag8.653 and spleen lymphocytes from mice immunized with each subunit. Non-competitive binding tests revealed that one of the MCAs against FSH beta (BF3B25) bound strongly to intact FSH and its beta subunit, but not FSH alpha, lutropin (LH), LH alpha, and LH beta. The immunoblotting results also showed a similar immunological specificity for BF3B25. Cross-reactivity of bullfrog FSH against BF3B25 was 19.4%, when compared with FSH beta in the competitive inhibition assay system. On the other hand, noncompetitive binding tests and immunoblotting results showed that one of the MCAs against FSH alpha (BF3A20) bound strongly to intact LH and FSH and their alpha subunits, but not their beta subunits. The inhibition curves obtained using the alpha subunits of LH and FSH were similar. In the sexually mature bullfrog pituitary, immunoreactive FSH cells stained with MCA BF3B25 were distributed throughout the pars distalis, except for the rostral region, and were polygonal in shape, with well-developed cytoplasm. With respect to distribution and histological characteristics, the immunoreactive LH cells were very similar to the immunoreactive FSH cells when consecutive sections were stained with LH beta-specific MCA (BL4B11). However, immunoreactive TSH cells, revealed by anti-human TSH beta serum, formed clusters in the ventrocentral region of the pars distalis. In young adult pituitary, almost all of the gonadotrophs showed the coexistence of FSH and LH, but some gonadotrophs contained only FSH. The number of immunoreactive alpha-subunit cells stained by BF3A20 was always higher than the sum of the numbers of cells stained by the three beta-subunit-specific antibodies.
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PMID:Immunocytochemical localization of the subunits of glycoprotein hormones (LH, FSH, and TSH) in the bullfrog pituitary gland using monoclonal antibodies and polyclonal antiserum. 210 16

Human monoclonal antibodies to human endocrine cells have been obtained following the generation of immunoglobulin-secreting interspecies lymphocyte hybridomas. Peripheral blood lymphocytes from an adult patient presenting with acute onset, Type I, diabetes mellitus were fused in vitro with mouse myeloma cells of the NS1 cell line. Initial selection of resulting hybridomas was made by their ability to proliferate in HAT medium. Those hybridomas secreting human immunoglobulins were identified by radioimmunoassay and, thereafter, cloned at frequent intervals to ensure continued antibody production. Human monoclonal antibodies selected in this manner are being employed to identify those epitopes which are common antigenic targets during initial stages of autoimmune-mediated diabetes mellitus and associated multiple endocrinopathies. Of these antibodies, one (HML 3.22) recognizes an epitope present on the human TSH receptor and a second (HML 3.21) identifies a component of thyroglobulin. The potential value of human monoclonal antibodies as probes for analyzing autoimmune-mediated endocrine diseases is discussed.
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PMID:Human monoclonal antibodies to thyroid antigens derived by hybridization of lymphocytes from a diabetic patient. 243 25

Human chorionic gonadotropin (HCG) is a 40,000 dalton glycoprotein composed of two non-identical alpha- and beta-subunits. HCG and other related pituitary hormones, such as human luteinizing hormones (HLH), human follicle stimulating hormone (HFSH), and human thyroid stimulating hormone (HTSH), consist of nearly identical alpha-chains. However, their beta-chains show a variable degree of amino acid sequence homology. Detection and subsequent quantitative determination of HCG in human biological fluids is useful in early diagnosis of pregnancy and in monitoring of tumor patients. For these applications monoclonal antibodies (McAbs) with defined specificity are required. Several hybridomas secreting McAbs to HCG have been isolated. The hybridoma cells have been developed by fusion of NS1 myeloma cells with spleen cells of Balb/C mice immunized with HCG. With the aid of an enzyme linked immunosorbent assay, six McAbs were characterized. McAbs A-73, A-76 and A-112 recognize an epitope present on the alpha-HCG subunit. McAbs B-68, B-69 and B-106 recognize an antigenic determinant associated with the beta-HCG subunit. Two of these McAbs: B-68 and B-69 are directed against an epitope on the B subunit specific to the HCG molecule and B-106 McAb towards an epitope common to HCG, TSH, LH and FSH molecule. In a hemagglutination test, only the A-73 McAb is capable of inducing agglutination of sheep red blood cells coated with HCG, thus suggesting that this McAb recognizes a repeating epitope on the alpha-HCG molecule.
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PMID:Development of monoclonal antibodies directed against different epitopes of human chorionic gonadotropin. 243 77

Four monoclonal antibodies to the thyrotropin (TSH) receptor were established by fusing human peripheral lymphocytes of patients from Graves' disease with a human myeloma cell line. Of two antibodies with TSH-binding inhibitory immunoglobulin activity (TBII), one inhibited TSH stimulation of adenylate cyclase and another stimulated adenylate cyclase. These antibodies showed competitive and noncompetitive modes of binding inhibition, respectively. Of the other two antibodies without TBII activity, one stimulated adenylate cyclase and the other inhibited TSH stimulation of adenylate cyclase. Of the two antibodies, which inhibited TSH stimulation of adenylate cyclase, one with TBII activity inhibited stimulation of adenylate cyclase by stimulating antibody with TBII activity, but another without TBII activity inhibited stimulation by both stimulating antibodies with or without TBII activity. These inhibitory antibodies did not influence the stimulation of adenylate cyclase by Forskolin and guanosine 5'-(beta,gamma-imido)triphosphate compounds which are known to affect other parts of the receptor-adenylate cyclase system than the receptor unit. Four antibodies with heterogeneous potencies to the TSH receptor reacted with glycoproteins extracted from thyroid membranes. One stimulating antibody without TBII activity also interacted with the glycolipid fraction of the membrane preparation, and the binding decreased after desialylation or deglycosylation of the membrane components. In order to identify the binding sites of these monoclonal antibodies, receptor proteins interacting with antibodies were visualized by Western blot analysis and by the label transfer cross-linking method. All of these antibodies with different characteristics reacted with a 56-kDa molecule.
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PMID:Monoclonal antibodies to the thyrotropin receptor bind to a 56-kDa subunit of the thyrotropin receptor and show heterogeneous bioactivities. 246 Apr 48

In the present work, using an immunological approach, we have investigated the existence of common epitopes between two receptors of the glycoprotein hormone family, lutropin (LH) and thyrotropin (TSH) receptors. We have immunized high responder mice with purified porcine LH receptors obtained by successive affinity chromatographies on agarose-human chorionic gonadotropin (hCG) gels. From one fusion of splenocytes with the murine myeloma NSC1, secreting hybridomas were tested for their anti-LH receptor specificities. During sequential selection for this activity including direct recognition of the purified LH receptors in dot-blot assays and displacement experiments of 125I-pLH and 125I-hCG binding to different sources of receptors, we performed a parallel investigation of their anti-porcine TSH receptor activities. Purified immunoglobulins from two of them showed a TSH-like activity on the iodide metabolism of porcine thyroid cell, this activity being related to the phosphoinositide breakdown pathway; moreover, these antibodies obtained after immunization with porcine LH receptors were able to immunopurify human TSH receptors. The double selection process led us to characterize three groups of immunoglobulins: exclusive specificities for lutropin receptors or thyrotropin receptors and cross-reactive specificities. Our results demonstrate the possibility of sequence homologies at the protein and the gene levels between the receptors for the glycoprotein hormone family supporting the hypothesis of a common origin in evolution.
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PMID:Lutropin receptor and thyrotropin receptor share a common epitope. 247 48

Using a recently described cell line derived from the fusion of human thyroid and human myeloma cells, we studied the effects of TSH on cell growth, iodide organification, and cAMP production. Although these cells grow in the absence of TSH, when incubated for 2 days in serum-free medium containing purified human or bovine TSH, there was a significant increase in cellular DNA content. The stimulatory effect was observed at concentrations as low as 0.5 microU/ml, which produced a significant increase in DNA content, and was maximal with 5 microU/ml. This effect was still present after 6 days of incubation. Electron microscopy performed by an unbiased observer on cells incubated in the presence of TSH showed an increase in the calculated size of the cells and the nucleus which was significant at 0.1 microU/ml and maximal at 1 microU/ml. Stimulation of 125I organification and hormone production was observed at TSH concentrations as low as 1 microU/ml and was maximal at 10 microU/ml. However, neither TSH (1-50 microU/ml) nor forskolin (10(-6) M) stimulated cAMP production. These data suggest that these cells lack a functional adenylate cyclase pathway and that growth and iodide organification are mediated by other second messenger systems. Such a cell line could yield new insights into the mechanisms of TSH action and may provide a sensitive bioassay for TSH and other thyrotropic factors.
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PMID:Thyrotropin induces growth and iodothyronine production in a human thyroid cell line without affecting adenosine 3',5'-monophosphate production. 284 54

We generated a high-affinity and highly specific monoclonal antibody (BL4B11)-producing hybridoma against bullfrog lutropin (LH) beta by fusing mouse myeloma, X63.Ag8.653, with spleen lymphocytes obtained from BALB/c mice immunized with bullfrog LH-IV (pI 9.3) beta-subunit. The resultant antibody-secreting hybridoma was injected into intraperitoneally pristane-primed BALB/c mice to obtain a large amount of antibody. Noncompetitive binding tests revealed that the ascitic fluid (BL4B11) could be diluted up to 1:12,000 for 50% binding to 125I-labeled bullfrog LH beta and also bound strongly to bullfrog intact LH, but not to LH alpha, follitropin (FSH), FSH alpha, FSH beta, and rat glycoprotein hormones (LH, FSH, and thyrotropin (TSH) significantly. The immunoblotting results also showed a similar immunological specificity of BL4B11. Cross-reactivities of bullfrog LH, FSH beta, FSH, LH alpha, and FSH alpha against BL4B11 were 9.69, 3.76, 2.40, 1, and 1%, respectively, when compared with bullfrog LH beta in the competitive inhibition assay system. The affinity constant (Ka) of the BL4B11 was 1.09 X 10(9) M-1. In the sexually mature bullfrog pituitary, immunoreactive LH cells which were revealed by this BL4B11 were distributed throughout the pars distalis except the rostral region. They were especially large, numerous, and polygonal, with well-developed cytoplasm. In the rostral region, immunoreactive LH cells were larger and more intense than those in the central region. In the case of young bullfrog, several immunoreactive LH cells were found only in the dorsocaudal region of the pars distalis. The distribution and histological characteristics of immunoreactive LH cells were different from those of immunoreactive TSH cells revealed by anti-human TSH beta serum.
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PMID:Production and characterization of a monoclonal antibody against the beta-subunit of bullfrog lutropin. 349 61

Human-human B-cell hybridomas were established using peripheral blood lymphocytes from patients with autoimmune thyroiditis and Graves' disease. Peripheral mononuclear cells (PMC), with or without mitogen prestimulation, were fused with HGPRT-negative human myeloma cell lines (Gm4672 and GM0462) using 44% polyethylene glycol. Developing hybridomas were screened by enzyme-linked immunosorbent assays (ELISAs) for human IgG and IgM and antibodies to human thyroglobulin (hTg) and microsomal antigen (M-Ag). A 125I-TSH binding inhibition assay was utilized for detecting antibodies to TSH receptor (TSH-R) protein. Hybridoma formation was observed only after prior mitogen stimulation of PMC. The amount of antibody secreted by the human-human hybridomas was highly variable (10 ng-100 micrograms/ml IgG/IgM). Nine and six-tenths percent of the hybrids secreted anti-hTg and 8.4% secreted anti-M-Ag. A 5% cloning efficiency was achieved, with detection of specific thyroid autoantibody secretion in one-third of the clones derived from positive hybridomas. Immunoglobulin secretion decreased with time and long-term stable clones were not achieved. Thyroid monoclonal autoantibodies to hTg, M-Ag, and TSH-R (IgG and IgM) detected during these studies were of a low affinity. In addition, antibodies were identified which exhibited marked specificity crossover between hTg, M-Ag, and nonthyroid antigens, suggesting the presence of recurrent epitopes. Such observations may help explain the multiplicity of thyroid autoantibodies in human thyroid disease and indicate a common defect in immunoregulation. We suggest that cross-reacting epitopes may be important in the derivation of thyroid-specific B-cell clones.
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PMID:A study of human-human hybridomas from patients with autoimmune thyroid disease. 355 36


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