Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human lymphocyte cultures produced large amounts of interferon after treatment with the enzyme galactose oxidase. Interferon production was detectable as early as 3 h after enzymatic treatment and reached a level of about 10(4) reference units 20 to 24 h later. Galactose oxidase-induced interferon appeared to be immune interferon on the basis of acid lability, lack of neutralization by antibody to leukocyte interferon, and slow kinetics of activation of the cellular antiviral state. Interferon production was inhibited to the same extent (99%) by pretreatment of the cells with beta-galactosidase or with neuraminidase followed by beta-galactosidase, suggesting that the critical event for activation of interferon production is the oxidation of exposed galactose residues on lymphocyte membrane.
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PMID:Enzymatic induction of interferon production by galactose oxidase treatment of human lymphoid cells. 11 35

Measles virus (MV)-specific murine helper T cell clones (Thy-1.2+, CD4+, CD8-) were generated from mice immunized with MV-infected mouse brain homogenate by limiting dilution and in vitro stimulation of spleen cells with UV-inactivated MV Ag. The protein specificity of 7 out of 37 stable T cell clones, which displayed MHC-restricted MV Ag recognition, could be assessed by using purified MV proteins. Two fusion (F) protein-specific, two hemagglutinin-specific, and three nucleoprotein- or matrix protein-specific clones were shown to be established. The F protein-specific T cell clones together with a panel of previously generated F protein-specific T cell clones were characterized for their fine specificity by using beta-galactosidase fusion products, which contained different parts of the F protein. It was shown that at least two epitopes on the major part of the F protein (amino acid 2-513) can be recognized by mouse T cells. Functional characterization of three T cell clones showed that they were able to assist MV-specific B cells and bystander B cells for antibody production. Furthermore, they were shown to produce the lymphokines IL-2 and IFN-gamma. It was also shown that these T cell clones induced a MV-specific delayed type hypersensitivity response. These observations suggest that all of the T cell clones characterized belong to the TH1 helper subset.
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PMID:Measles virus-specific murine T cell clones: characterization of fine specificity and function. 252 70

Heterogeneity of human gamma interferon (IFN-gamma) induced by the combined treatment with OK-432 and Staphylococcal enterotoxin B (SEB) was demonstrated by chromatofocusing. Treatment of IFN-gamma with a mixture of neuraminidase, and beta-galactosidase eliminated the charge heterogeneity. Apparent molecular weight of IFN-gamma was decreased by enzyme treatment. These results suggest that the heterogeneity of IFN-gamma induced in our system was the result of the difference in the content of sialic acids.
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PMID:Effect of glycosidases on the properties of human interferon gamma. 642 24

The serum glycoprotein alpha 2-macroglobulin can be converted into a potent macrophage-activating factor that promotes the Fc gamma receptor-mediated phagocytosis of macrophages, through modification of the sugar moiety with liposome-treated B-cell glycosidase(s). This paper discusses the activation mechanism of B-cell membranous glycosidase by liposomes using mouse splenic B cells. B-cell membranous beta-galactosidase and beta-N-acetylglucosaminidase were significantly activated by liposome treatment, and this process can be regulated by trypsin-sensitive protein. To clarify the contribution of trypsin-sensitive protein to enzyme activities, the B-cell surface antigen receptor was studied. With the addition of a Fab' fragment of anti-mouse IgM but not IgD antibody, the activation of both glycosidases induced by liposomes was significantly inhibited and was essentially the same as that of saline-treated glycosidase activities. Consequently, interactions of liposomes with cell-surface IgM may cause B-cell membranous glycosidase activation. A significant decrease in membrane fluidity, particularly near the membrane surface rather than deep within the membrane, was observed in liposome-treated B cells using electron spin resonance. Liposomes would thus appear to interact with B cells via cell-surface IgM, with a consequent decrease in membrane fluidity, as well as the activation of B-cell membranous glycosidases, causing alpha 2-macroglobulin to be converted into a macrophage activating factor.
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PMID:Modification of alpha 2-macroglobulin into a macrophage-activating factor through the action of liposome-stimulated B-cell membranous glycosidases. 759 Aug 82

The outer surface of mouse B lymphocytes carries constitutive and inducible beta-galactosidase isozymes. A brief (30 min) treatment of B lymphocytes with lysophosphatidylcholine (lyso-Pc) immediately induced an approximate 3-fold higher beta-galactosidase activity than the constitutive isozyme of untreated B lymphocytes. Thus, the lyso-Pc-inducible isozyme is not a de novo enzyme. Outer surface of mouse T lymphocytes carries constitutive (non-Neu-1) and inducible (Neu-1) sialidase isozymes. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and the Neu-1 sialidase of T lymphocytes were required for conversion of vitamin D3-binding protein (Gc protein) to a potent macrophage activating factor. This enzymatic generation of the macrophage activating factor was mediated via enzyme-associated receptors.
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PMID:Roles of beta-galactosidase of B lymphocytes and sialidase of T lymphocytes in inflammation-primed activation of macrophages. 772 26

Highly conserved DBP (human DBP is known as Gc) of serum alpha 2-globulin fraction can be converted to a potent macrophage activating factor by stepwise modification of Gc glycoprotein with beta-galactosidase of B cells and sialidase of T cells. These glycosidases, beta-galactosidase and sialidase, are membrane bound and not soluble in culture medium. Thus, consecutive contact of Gc protein with B cells and T cells, presumably via specific receptors, is required for conversion of Gc glycoprotein to the macrophage activating factor. The essential role of T cell sialidase in macrophage activation was confirmed by the finding that peritoneal nonadherent cells of SM/J mouse, whose T cells are deficient in sialidase activity, were unable to convert Gc protein to the macrophage activating factor and thus did not activate macrophages. Treatment with sialidase of a conditioned medium of lipid metabolite-treated SM/J mouse nonadherent cells efficiently generated the macrophage activating factor. When Gc protein was first treated with soluble or immobilized sialidase and used in a medium for 2 h cultivation of lipid metabolite-treated SM/J mouse nonadherent cells or BALB/c mouse B cells, the resultant conditioned media contained a large amount of the macrophage activating factor. These results support the hypothesis that Gc protein carries a dibranched trisaccharide with galactose and sialic acid termini.
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PMID:Conversion of vitamin D3 binding protein (group-specific component) to a macrophage activating factor by the stepwise action of beta-galactosidase of B cells and sialidase of T cells. 836 Apr 93

Recombinant viruses with the lacZ gene placed under the control of the HSV-1 ICP4, TK and gD regulatory regions were constructed by recombination into the TK locus of HSV-1. Difficulty in isolating ICP4 and gD recombinant viruses with high level, regulated expression of beta-galactosidase was overcome by the use of HSV-1 translational initiation sequences of these genes in place of vector-derived sequences. beta-Galactosidase expression displayed the kinetics particular to each viral class. The maximal expression of beta-galactosidase from the recombinant viruses within a 22-h period (m.o.i. 5) (relative to the ICP4 virus) was gD(3) > gC(2) > ICP4(1) > TK(0.5). The ICP4 virus produces easily quantifiable levels of beta-galactosidase activity for multiplicities of infection from 5 x 10(-4) through 5 over 48 h postinfection. At multiplicities of infection between 2 and 5, ICP4-driven activity was measurable within 2 h postinfection from a monolayer of 3 x 10(4) Vero cells in microtiter wells. Mechanisms of inhibition of several antivirals were probed by using the regulated expression of beta-galactosidase from the ICP4 virus as a marker for viral growth. An experimental antiviral (E3925, IC50 1 microgram/ml) and a neutralizing gD MAb (DUP55306, IC50 0.6 microgram/ml) acted prior to immediate early synthesis, consistent with inhibition of viral entry or uncoating. IFN-gamma inhibited expression of immediate-early synthesis, while having no effect on viral entry. IC50 values for E3925 obtained using either the ICP4 or gD viruses at m.o.i. 0.005, were in good agreement with those obtained by standard plaque assays, but were determined in only 1 day, using a microtiter plate format. Thus, these reporter viruses are useful tools for defining the mechanisms of action of antiherpes agents, while quantitatively reproducing the results for IC50 determinations from standard plaque assays within 24 h in a microtiter plate format.
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PMID:Herpes simplex type 1:lacZ recombinant viruses. I. Characterization and application to defining the mechanisms of action of known antiherpes agents. 862 13

When rat peritoneal nonadherent cells were treated with inflammatory lipid metabolites and cultured with adherent cells in 1% fetal calf serum (FCS) supplemented medium RPMI 1640 (FCS medium) for 3 hr, markedly enhanced phagocytic and superoxide generating capacities of macrophages were observed. Stepwise preparation of conditioned medium of lysophosphatidylcholine (lyso-Pc)-treated B cells and untreated T cells in FCS medium generated a potent macrophage activating factor whereas cultivation of lyso-Pc-treated B cells alone in a 1% adult rat serum supplemented medium efficiently generated the macrophage activating factor. Generation of macrophage activating factor requires a precursor protein, serum vitamin D3-binding protein (DBP), as well as participation of lymphocyte glycosidases. The lyso-Pc-inducible beta-galactosidase of B lymphocytes and the Neu-1 sialidase of T lymphocytes modified bovine DBP (bDBP) to yield the macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. In contrast, lyso-Pc-inducible beta-galactosidase of B cells alone modified rat DBP (rDBP) to yield the macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Thus, we conclude that bDBP carries a trisaccharide composed of N-acetylgalactosamine, galactose, and sialic acid while rDBP carries a disaccharide composed of N-acetylgalactosamine and galactose.
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PMID:Vitamin D3-binding protein as a precursor for macrophage activating factor in the inflammation-primed macrophage activation cascade in rats. 866 Aug 14

Serum vitamin D3-binding protein (Gc protein) can be converted by beta-galactosidase of B cells and sialidase of T cells to a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is the precursor of the macrophage activating factor (MAF). Treatment of Gc protein with immobilized beta-galactosidase and sialidase generates an extremely high titered MAF, Gc-MAF. When peripheral blood monocytes/macrophages of 52 patients bearing various types of cancer were incubated with 100 pg/ml of GcMAF, the monocytes/macrophages of all patients were efficiently activated. However, the MAF precursor activity of patient plasma Gc protein was found to be severely reduced in about 25% of this patient population. About 45% of the patients had moderately reduced MAF precursor activities. Loss of the precursor activity was found to be due to deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase detected in the patient's bloodstream. The source of the enzyme appeared to be cancerous cells. Radiation therapy decreased plasma alpha-N-acetylgalactosaminidase activity with concomitant increase of precursor activity. This implies that radiation therapy decreases the number of cancerous cells capable of secreting alpha-N-acetylgalactosaminidase. Both alpha-N-acetylgalactosaminidase activity and MAF precursor activity of Gc protein in patient bloodstream can serve as diagnostic and prognostic indices.
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PMID:Deglycosylation of serum vitamin D3-binding protein leads to immunosuppression in cancer patients. 866 21

The immunogenic properties of a replication-defective herpes simplex virus HD-2, containing the Escherichia coli lacZ gene under control of the HSV ICP8 early gene promoter were studied in BALB/c mice. Experiments were designed to determine if the HD-2 virus preferentially stimulated either Th1- or Th2-associated immune responses to beta-galactosidase (beta gal). Sera from mice immunized i.p. or s.c. with virus HD-2, beta gal on aluminum phosphate adjuvant, or a control ICP8 deletion mutant, d301, were assayed for total and Ag-specific IgG1 and IgG2a Abs, beta gal-driven lymphocyte proliferation, and in vitro production of the cytokines IFN-gamma, IL-4, and IL-2. Viruses HD-2 and d301 preferentially stimulated the production of total serum IgG2a following two immunizations i.p. or a single immunization s.c., while only HD-2 virus stimulated in vivo production of beta gal-specific IgG2a serum Abs. In contrast, beta gal adsorbed on AIPO4 preferentially stimulated production of Ag-specific IgG1 serum Abs. The HD-2 virus also induced a potent cellular proliferative response to beta gal, which was still pronounced 5 wk after primary immunization. Cultured lymphocytes from HD-2-immunized mice produced IFN-gamma after 5 days in culture with soluble beta gal in an Ag- and dose-dependent fashion. These results demonstrate that replication-defective mutants of HSV can be used as vectors for eliciting Th1-associated immune responses to a heterologous Ag expressed from the viral genome.
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PMID:Th1-associated immune responses to beta-galactosidase expressed by a replication-defective herpes simplex virus. 875 44


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