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)

The peripheral blood of most normal individuals has been shown to contain T cells that respond to beta-galactosidase (beta-Gal), presumably as a result of natural priming. Three T cell clones (clones 1,2,4) specific for beta-Gal were isolated from peripheral blood mononuclear cells (PBMC) after pretreatment with leucine methyl ester (LeuOMe); a fourth clone from the same individual was isolated from untreated cells. All four clones were CD4+ CD8- alpha beta TcR+ and clone 1 was additionally shown to be cytotoxic. Epstein-Barr virus (EBV) transformed B cell lines were derived from LeuOMe-treated or untreated PBMC and used to study the efficiency of presentation of beta-Gal to one of the clones. The results indicated that B cells transformed after LeuOMe treatment presented beta-Gal at lower concentrations than untreated controls. beta-Gal would therefore appear to be a highly suitable model antigen for studies of immunoregulation in humans.
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PMID:Human T cell responses to beta-galactosidase. 184 91

The Tac antigen component of the bovine interleukin-2 receptor was expressed as a Cro-beta-galactosidase fusion protein in Escherichia coli and used to raise antibodies in rabbits. These antibodies were used for flow cytofluorimetric analysis to investigate the expression of Tac antigen in a variety of Theileria parva-infected cell lines and also in three Theileria annulata-infected cell lines. Cells expressing Tac antigen on their surface were found in all T. parva-infected cell lines tested whether these were of T- or B-cell origin. T cells expressing Tac antigen could be CD4- CD8-, CD4+ CD8-, CD4- CD8+, or CD4+ CD8+. Tac antigen expression was observed both in cultures which had been maintained in the laboratory for several years and in transformed cell lines which had recently been established by infection of lymphocytes in vitro with T. parva. Northern (RNA) blot analysis demonstrated Tac antigen transcripts in RNA isolated from all T. parva-infected cell lines. Three T. annulata-infected cell lines which were not of T-cell origin were also tested. Two of them expressed Tac antigen on their surface. Abundant Tac antigen mRNA was detected in these T. annulata-infected cell lines, but only trace amounts were demonstrated in the third cell line, which contained very few Tac antigen-expressing cells. In all cell lines tested, whether cloned or uncloned, a proportion of the cells did not express detectable levels of Tac antigen on their surface. This was also the case for a number of other leukocyte surface markers. In addition, we showed that the interleukin-2 receptors were biologically functional, because addition of recombinant interleukin-2 to cultures stimulated cell proliferation. Recombinant interleukin-2 treatment also resulted in increased amounts of steady-state Tac antigen mRNA. The relevance of interleukin-2 receptor expression on Theileria-infected cells is discussed.
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PMID:Expression of Tac antigen component of bovine interleukin-2 receptor in different leukocyte populations infected with Theileria parva or Theileria annulata. 197 17

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

Panning was used to select co-transfected cells expressing plasmid-encoded ion channels. Adherent cells were cotransfected by the CaPO4 method with a plasmid encoding a cell surface marker (CD8) along with another plasmid encoding an ion channel. At 1-3 days post-transfection, the cells were suspended, treated with a biotinylated CD8-specific antibody and placed into streptavidin-coated bacterial petri dishes. After 2 h, these dishes were washed with a saline solution to remove cells that did not adhere to the streptavidin-coated dishes. By using molar ratios of > or = 8:1 of the ion channel encoding plasmid to the CD8 plasmid, we found that > or = 50% of the panned cells that adhered to coated dishes were positive for expression of the co-selected gene. Cells expressing plasmid-encoded channels (voltage-dependent sodium channels or cystic fibrosis transregulator chloride channels) were assayed using whole-cell recording, perforated-patch recording and single-channel recording. The method was tested on tsA201 and NIH3T3 cells, the latter of which transfected very poorly (usually < 4% efficiency) with our standard protocols. When the co-selected plasmid encoded the bacterial beta-galactosidase gene, it was possible to determine by histological assay the percentage of positively transfected cells (with and without panning). Panning in some cases increased the percentage of positively cotransfected cells by more than 20-fold. This technique is particularly useful when selecting co-transfected cells for electro-physiological recordings on individual cells.
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PMID:Panning transfected cells for electrophysiological studies. 750 2

The interactions between CD4 or CD8 and p56lck were tested using the two-hybrid protein interaction system in yeast. Plasmid constructs were created which fuse the cytoplasmic domains of either CD4 or CD8 alpha to the DNA-binding protein LexA, and the unique amino-terminal domain of p56lck fused to a transcriptional activation domain. These constructs were transfected into yeast bearing lacZ and LEU2 reporter genes controlled by upstream LexA operator sequences. Yeast transfectants bearing either CD4 or CD8 alpha hybrid proteins in combination with the amino terminal p56lck hybrid protein exhibited increased beta-galactosidase activity and growth on leucine-deficient medium, indicating interactions between these protein domains. Quantitation of reporter activation indicated that the interaction of p56lck with CD8 alpha is at least 18-fold weaker than the interaction with CD4 in this assay. This reduced interactive capacity is apparently not due to competition by CD8 alpha interacting with itself, since homotypic or heterotypic interactions between CD8 alpha and/or CD4 could not be detected. Truncation and point mutants demonstrated that the interactions of p56lck with CD4 or CD8 alpha were dependent on the integrity of a pair of cysteines on each protein. The results indicate that these interactions do not require any additional proteins. Additionally, expression of the entire p56lck molecule as a hybrid with LexA resulted in dramatic reduction in the growth of yeast. Though the two-hybrid system is a powerful tool for examining protein interactions, this result indicates potential limitations in studying full-length src family tyrosine kinases in yeast.
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PMID:Interactions between the amino-terminal domain of p56lck and cytoplasmic domains of CD4 and CD8 alpha in yeast. 766 3

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

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

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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