Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A transgenic mouse system has been established to follow the pattern of IL-2 expression at the level of single T cells. This was achieved by introducing a human IL-2 promoter-driven reporter gene (Escherichia coli lacZ) into the germline of mice and monitoring its product, beta-galactosidase (beta-gal), by FACS analysis. Ex vivo experiments confirmed that the regulated expression of the transgene is comparable with that of the endogenous IL-2 gene. Transgene expression is inducible by mitogens, restricted to T cells, and diminished by immunosuppressive agents, such as cyclosporin A, at concentrations known to suppress IL-2 transcription. Depending on the mitogens used, 30-50% of peripheral T cells produced IL-2 with an asynchronous induction pattern, as measured by transgenic beta-gal activity. Both helper (CD4+CD8-) and cytotoxic T cells (CD4-CD8+) respond with comparable heterogenous expression levels but they show different frequencies of beta-gal production. Transgenic beta-gal-producing T cells were detectable as early as 2 h after mitogen stimulation. These cells represent a transitional IL-2 secreting, IL-2 receptor alpha-chain negative T cell population, which occurs in the autocrine process of T cell activation. Administration of staphylococcal enterotoxin A (SEA), a bacterial superantigen, resulted in a T cell specific (Thy-1.2) increase (2.5-fold) of reporter gene expression in vivo. In summary, we could demonstrate that IL-2 promoter-driven reporter gene expression in transgenic mice is a sensitive tool to characterize IL-2 expressing cells phenotypically.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:IL-2 promoter-driven lacZ expression as a monitoring tool for IL-2 expression in primary T cells of transgenic mice. 815 96

We previously developed a method for introducing foreign genes into liver tissue using liposomes with incorporated hemagglutinating virus of Japan (HVJ, Sendai virus), and found that liver cells transfected with the E. coli beta-galactosidase gene or the gene for hepatitis B virus (HBV) surface protein (HBsAg) expressed these proteins in vivo. Here, we analyzed cellular reactions leading to hepatitis in the liver by expressing the genes of HBV in vivo. Lymphocytes were eluted directly from liver transfected with the HBsAg genes and shown to be cytotoxic only to cells expressing HBsAg in vitro. These lymphocytes were identified as cytotoxic T lymphocytes with the CD4- CD8+ phenotype. Transfer of these lymphocytes to transgenic mice with the whole HBV genome led to elevation of the serum glutamic-pyruvic transaminase (SGPT) level, indicating the induction of hepatitis due to the cytotoxic T lymphocytes in vivo. Similarly, direct transfer of the gene for the HBV secretory core protein (HBeAg) induced expression of HBeAg in hepatocytes and the appearance of antibody against HBeAg in the serum. However, using this system, we found that the lymphocytes infiltrating the transfected liver showed no cytotoxicity specific for HBeAg. These results indicate that expression of HBsAg, one of the components of virions, in animal liver induced hepatitis efficiently through generation of specific cytotoxic T lymphocytes (CTL) without any expression of the other viral components. This in vivo experimental system should be useful for evaluating how expression of a given gene induces cellular reactions and intrinsic functions in the living body.
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PMID:Use of the hemagglutinating virus of Japan (HVJ)-liposome method for analysis of infiltrating lymphocytes induced by hepatitis B virus gene expression in liver tissue. 839 62

Antigens in extracellular fluids can be processed and presented with major histocompatibility complex (MHC) class I molecules by a subset of antigen presenting cells (APCs). Chicken egg ovalbumin (Ova) linked to beads was presented with MHC class I molecules by these cells up to 10(4)-fold more efficiently than soluble Ova. This enhanced presentation was observed with covalently or noncovalently linked Ova and with beads of different compositions. A key parameter in the activity of these conjugates was the size of the beads. The APC that is responsible for this form of presentation is a macrophage. These cells internalize the antigen constructs through phagocytosis, since cytochalasin B inhibited presentation. Processing of the antigen and association with MHC class I molecules appears to occur intracellularly as presentation was observed under conditions where there was no detectable release of peptides into the extracellular fluids. When injected in vivo in C57BL/6 mice, Ova-beads, but not soluble Ova, primed CD4- CD8+ cytotoxic T lymphocytes (CTLs). Similar results were obtained in BALB/c mice immunized with beta-galactosidase-beads. The implications of these findings for development of nonliving vaccines that stimulate CTL immunity are discussed.
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PMID:Efficient major histocompatibility complex class I presentation of exogenous antigen upon phagocytosis by macrophages. 850 38

Myoblasts were grown from monkey muscle biopsies and infected in vitro with a defective retroviral vector containing a cytoplasmic beta-galactosidase (beta-gal) gene. These myoblasts were then transplanted to 14 different monkeys, 6 of which were immunosuppressed with FK506. Without immunosuppression, only a few myoblasts and myotubes expressing beta-gal were observed 1 week after the transplantation, but no cells expressing beta-gal were observed after 4 weeks. This result was attributed to immune responses since infiltration by CD4+ or CD8+ lymphocytes was abundant 1 week after transplantation but not after 4 weeks. The expression of interleukin 6 (IL-6), interleukin 2 (IL-2), granulocyte/macrophage colony stimulating factor (GM-CSF), transforming growth factor-beta (TGF-beta) and granzyme B mRNAs was increased in the myoblast-injected muscle indicating that the infiltrating lymphocytes were activated. Moreover, antibodies against the donor myoblasts were detected in 3 out of 6 cases. When the monkeys were immunosuppressed with FK506, muscle fibers expressing beta-galactosidase (beta-gal) were present 1, 4 and 12 weeks after the transplantation. There was neither significant infiltration by CD4 or CD8 lymphocytes, nor antibodies detected. The mRNA expression of most cytokines was significantly reduced as compared to the nonimmunosuppressed monkeys. These results indicate that FK506 is effective in controlling short-term immune reactions following myoblast transplantation in monkeys and suggest that it may prove useful for myoblast transplantation in Duchenne Muscular Dystrophy patients.
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PMID:Myoblast transplantation in monkeys: control of immune response by FK506. 864 94

Thymic epithelium is involved in negative selection, but its precise role in selecting the CD4 T cell repertoire remains elusive. By using two transgenic mice, we have investigated how medullary thymic epithelium (mTE) and bone marrow (BM)-derived cells contribute to tolerance of CD4 T cells to nuclear beta-galactosidase (beta-gal). CD4 T cells were not tolerant when beta-gal was expressed in thymic BM-derived cells. In contrast, CD4 T cells of mice expressing beta-gal in mTE were tolerized. Tolerance resulted from presentation of endogenous beta-gal by mTE cells but not from cross-priming. mTE cells presented nuclear beta-gal to a Th clone in vitro, while thymic dendritic cells did not. The data indicate that mTE but not thymic BM-derived cells can use a MHC class II endogenous presentation pathway to induce tolerance to nuclear proteins.
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PMID:CD4 T cell tolerance to nuclear proteins induced by medullary thymic epithelium. 867 1

Gene transfer into the pancreas would be useful for the treatment of a variety of disorders, including cystic fibrosis, diabetes, cancer, and immunomodulation of pancreatic allografts. A hypothesis that various cell populations in the pancreas could be targeted by recombinant adenoviruses was developed and tested. Gene transfer into the rat ductal epithelium, acinar cells, and islets of Langerhans was accomplished with a recombinant adenovirus containing bacterial beta-galactosidase by retrograde delivery of adenovirus into the pancreaticobiliary duct. Maximal gene expression was observed at 3 days and correlated with DNA blot analysis. Histologic analysis of sections from pancreatic tissue in the adenovirus-treated rats demonstrated severe pancreatitis. Immunophenotyping of the inflammatory infiltrate with rat lymphocyte-specific markers showed CD45-, CD8-, and CD4-positive cells. Tissue injury resolved as gene expression was lost, with both features absent by 21 days. Pancreatic regeneration was documented by the presence of 5-bromo-2'-deoxyuridine-positive staining cells. Pancreatic gene transfer with first-generation recombinant adenoviruses can be accomplished by techniques applicable to clinical situations. The use of first-generation recombinant adenoviruses for pancreas-directed gene transfer is limited by the development of inflammation and transient expression.
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PMID:Adenovirus-mediated in vivo gene transfer and expression in normal rat pancreas. 874 Apr 9

Correlations between the in vitro biological properties of HIV strains isolated from patients and the prognosis of their disease have been reported. We developed a technique to study the phenotype of HIV strains isolated from patients. We used the P4 cell line, derived from HeLa cells, which has been transfected with receptor CD4 gene. HIV laboratory strain (HIVLAI) and peripheral blood leukocytes (PBLs) from donors infected with HIVLAI induce syncytium in P4 cell cultures in vitro. The presence of reporter gene (LacZ gene) under the control of the HIV-1 long terminal repeat (LTR) in these cells allows colorimetric visualization of syncytia in the cytoplasm using a beta-galactosidase (beta gal) assay in the presence of X-gal. We cocultivated 1 x 10(6) patient PBLs with 2 x 10(6) normal PHA-activated normal PBLs for 4 days in the presence of IL-2 in 24-well plates. Half of the medium was replaced twice a week and PHA-activated normal PBLs were added every 7 days. HIV-1 was isolated from cocultured PBLs of 18 patients with advanced-stage HIV infection as assessed by the production of HIV p24 detected with a commercially available HIV-1 p24 ELISA. Supernatant and 10(5) cells were collected twice a week from cocultured PBLs and were added to P4 cells in 96-well microtiter plates. The cultures were observed every day for 3 days and then the beta gal assay was performed. We did not observe any effect with cells and supernatant from 8 patients, harvested from cultures incubated for as long as 28 days. The phenotype of these isolates was called NC (noncytopathic). In cells from 2 patients, we obtained blue multinucleated giant cells; the phenotype of these strains was called SI (syncytium inducing). In cultures from 8 other patients, we obtained the death of P4 cells without syncytium formation, and the phenotype of these strains was called CI (cell-killing inducing). In every case, the cytopathic effect of HIV-1 isolates could be detected with cocultured PBLs collected as early as day 4 of culture. Cocultured PBLs from 13 healthy controls did not alter the P4 cells. We displayed the replication of CI strains of HIV-1, but not the one of NC strains in P4 cell line. Our micromethod allowed the detection of cytopathic effects of HIV isolates. Further investigations should define the clinical applications of this method.
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PMID:A microassay for determination of the cytopathogenicity of human immunodeficiency virus type-1 isolates. 880 3

In many organs, E1-deleted human adenovirus vectors trigger antiviral T cell responses which limit the duration of vector-encoded gene expression. When injected into the brain, however, long-term expression is possible in spite of the ensuing inflammatory response. To examine the role of T cells in the immune response in the brain, monoclonal antibodies were used to systemically deplete CD4+ and/or CD8+ T cell subsets from mice at the time of vector injection. The early phase of the inflammatory response, characterized by high MHC I expression and recruitment of mononuclear cells, was unaffected by T cell depletion. Six days after injection, however, inflammation was markedly reduced by CD8-depletion and eliminated by CD4-depletion. Vector expression of the marker protein beta-galactosidase did not differ between depleted and undepleted mice. In contrast, when mice had been previously exposed to adenovirus vector in the periphery, beta-galactosidase expression in the brain was transient, showing that T cells can effectively target vector-transduced cells in this organ. We conclude that adenovirus vectors are able to achieve long-term expression in the brain because such a route of injection triggers an ineffective T cell response.
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PMID:Role of T cells in inflammation caused by adenovirus vectors in the brain. 881 53

The therapeutic potential of adenovirus-mediated gene transfer using first-generation vectors is severely limited by the fact that only transient expression is achievable in immunocompetent animals. The loss in transgene expression can be attributed at least in part to the appearance of detrimental immune responses directed toward vector and/or transgene-encoded determinants. FK506 and cyclosporin A both reduced these immune responses. These immunosuppressants, however, may induce many severe side effects during prolonged use. An alternative strategy has been developed to overcome these problems following in vivo transfection of muscles of adult immunocompetent mice with a delta E1/E3a adenoviral vector encoding a beta-galactosidase (beta-Gal) expression cassette. YTS 177 (an anti-CD4 monoclonal antibody) as well as CTLA4Ig, a recombinant protein, partially controlled the immune responses. They were indeed able to reduce the muscle infiltration by CD4+ and CD8+ cells but they failed to repress the humoral response. Co-administration of YTS 191 (an anti-CD4), YTS 169 (an anti-CD8), and TIB 213 (an anti-CD11a) was, however, very efficient in blocking both cellular and humoral immune reactions. This combination of monoclonal antibodies allowed strong and stable transgene expression over 1 month. These data underline the potential of monoclonal antibodies as immunosuppressive adjunct treatment for adenovirus-mediated gene transfer.
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PMID:Prevention of immune reactions triggered by first-generation adenoviral vectors by monoclonal antibodies and CTLA4Ig. 884 5

Various combinations of monoclonal antibodies specific for lymphocyte cell surface antigens and a recombinant molecule (CTLA4-Ig) were used to immunosuppress mice after transplantation of MHC-incompatible myoblasts. To assess the effectiveness of the immunosuppression, the donor myoblasts were obtained from a transgenic mouse (TnI LacZ1/29) containing a beta-galactosidase (beta-gal) reporter gene under the control of a muscle-specific promoter. No muscle fibers expressing beta-gal were observed 1 month after the myoblast transplantation, when the animals were not immunosuppressed or were treated with CTLA4-Ig alone. Approximately 50% of the muscle fibers expressed the beta-gal reporter gene 1 month after transplantation in mice treated with CTLA4-Ig combined with an anti-CD4 monoclonal antibody and in mice treated with a combination of anti-CD4, anti-CD8, and anti-lymphocyte function-associated antigen-1. The percentage of beta-gal-labeled muscle fibers increased to 94% when this combination of the three monoclonal antibodies was administrated weekly for 3 weeks. Although excellent graft survival rates were obtained 1 month after transplantation, reflecting an effective immunosuppression by these three treatments, no beta-gal-positive fibers were found 2 months after the transplantation, indicating the inability of these immunosuppressive agents to maintain long-term graft survival and induce tolerance to the myoblasts and muscle fibers of donor origin.
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PMID:Immunosuppression with monoclonal antibodies and CTLA4-Ig after myoblast transplantation in mice. 887 91


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