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

---

Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

T lymphocytes are a promising cell vehicle for gene therapy purposes. By cocultivating retroviral vector producing cells and target cells, highly efficient gene transfer was achieved with activated human T lymphocytes derived from peripheral blood with vectors carrying different forms of the bacterial beta-galactosidase gene including the regular LacZ gene, the Sh-ble::LacZ gene and the nlsLacZ gene. Infection kinetics of T cells activated by a combination of monoclonal antibodies directed against CD2 and CD28 indicated that the highest efficiencies of transduction were obtained when the cocultivation began 4 days after stimulation. In fact, with the FLac vector, a new retroviral vector which expresses the Sh-ble::LacZ gene, we observed up to 78% transduction efficiency assessed by X-gal staining performed 2 days after the end of the cocultivation. Expression of the transduced genes was observed throughout the period of culture. Neither the cocultivation step nor the expression of the transduced Sh-ble::LacZ gene altered cell culture proliferation or the expression of selected cell surface antigens. In addition, we showed that CD4+ and CD8+ T cells were equally transduced.
...
PMID:Highly efficient retroviral gene transfer into human primary T lymphocytes derived from peripheral blood. 762 16

IL-2-mediated T cell proliferation is a critical early event in the inflammatory process. Formation of the NFAT-1 transcriptional complex on the IL-2 promoter is essential for IL-2 transcription. Using a cell line that is stably transfected with a trimer of the NFAT-1 regulatory element linked to a lac-Z reporter gene, we screened for inhibitors of NFAT-1-mediated beta-galactosidase activity. WIN 61058 and WIN 53071 were identified as microM inhibitors. These compounds also inhibited beta-galactosidase mRNA levels. Similar inhibition of NFAT-1-mediated gene expression was observed in a second cell line, which is stably transfected with NFAT-1 regulatory elements linked to the reporter gene for sCD8. At 10 microM, both compounds inhibited IL-2 mRNA and protein levels in the NFAT-1-linked lac-Z transfectants, and in human lymphocytes. Both compounds inhibited the mixed lymphocyte reaction, and this inhibition was reversed by exogenous IL-2. WIN 53071 inhibited IL-2 production induced in the calcium-dependent PMA and ionomycin pathway. Conversely, calcium-independent anti-CD28 Ab and PMA-induced IL-2 production was resistant. Both compounds altered the NFAT-1 transcriptional complex, causing its retarded mobility on gels. By these functional criteria, we believe we have identified two structurally distinct, novel inhibitors of NFAT-1-mediated transcription.
...
PMID:Functional characterization of novel IL-2 transcriptional inhibitors. 770 10

CD28 is a 44 kDa Ig superfamily cell surface molecule expressed on most mature T cells. Through its interaction with the recently identified B7/BB1 counter-receptor, it is believed to play an important role as a co-stimulator of T cells along with the TCR-CD3 complex. Activation of T cells with CD28 mAbs synergizes with TCR-CD3 and CD2 stimulation, resulting in long term T cell proliferation, differentiation of cytotoxic T cells and production of large amounts of cytokines. In order to further delineate the role of CD28 in signal transduction and T cell activation, human CD28 was transfected into CD3+ murine T cell hybridomas. High levels of cell surface CD28 expression was achieved by protoplast fusion. The transfected molecule retained all the native CD28 mAb epitopes found on human T cells. In these transfectants, CD28 mAbs, similarly to CD3 mAbs, were able to induce Ca2+ mobilization, IL-2 promoter induction (measured as beta-galactosidase activity in T cells hybridomas pre-transfected with the IL-2-lac Z reporter gene), IL-2 secretion, TNF alpha production and apoptosis (observed as growth arrest and genome fragmentation). The parental host cells, or cells transfected with vector alone, responded only to mAbs to CD3. IL-2 secretion in the transfectants was obtained using either an IgM mAb to CD28 or IgG mAbs presented on the surface of IgG-FcR+ B lymphoma cells. Optimal activation via CD28 was inhibited by suboptimal concentrations of soluble CD3 mAb, suggesting an interaction between the two pathways. The immunosuppressive drugs Cyclosporin A and FK506 completely blocked CD28 and CD3 mediated IL-2 production in these transfectants whereas rapamycin had only a partial inhibitory effect. Finally, since the transfected human CD28 molecule confers full functional responsiveness to the murine T cell hybridomas without the need for costimulators such as PMA, this model is ideal for studying the structure-function relationships of the CD28 molecule as well as the transmembrane and cytoplasmic associations implied in CD28 signaling.
...
PMID:Functional expression of human CD28 in murine T cell hybridomas. 830 98

The mechanism of action of the immunosuppressive drug cyclosporin A (CsA) is the inactivation of the Ca2+/calmodulin-dependent serine-threonine phosphatase calcineurin by the drug-immunophilin complex. Inactive calcineurin is unable to activate the nuclear factor of activated T cells (NFAT), a transcription factor required for expression of the interleukin 2 (IL-2) gene. IL-2 production by CsA-treated cells is therefore dramatically reduced. We demonstrate here, however, that NFAT can be activated, and significant levels of IL-2 can be produced by the CsA-resistant CD28-signaling pathway. In transient transfection assays, both multicopy NFAT- and IL-2 promoter-beta-galactosidase reporter gene constructs could be activated by phorbol 12-myristate 13-acetate (PMA)/alpha-CD28 stimulation, and this activation was resistant to CsA. Electrophoretic mobility shift assay showed the induction of a CsA-resistant NFAT complex in the nuclear extracts of peripheral blood T cells stimulated with PMA plus alphaCD28. Peripheral blood T cells stimulated with PMA/alphaCD28 produced IL-2 in the presence of CsA. Collectively, these data suggest that NFAT can be activated and IL-2 can be produced in a calcineurin independent manner.
...
PMID:Activation of nuclear factor of activated T cells in a cyclosporin A-resistant pathway. 863 9

The Src family protein tyrosine kinase Fyn (p59fyn) plays an important role in thymocyte development and T cell receptor (TCR) signal transduction. Fyn has been shown to associate with the TCR-CD3 complex, the protein tyrosine phosphatase CD45 and several co-receptors such as CD28 which are crucial for initiating T cell activation and proliferation. The molecular basis of how Fyn is associated with these transmembrane proteins is largely unknown. To investigate the Fyn association with the TCR-CD3 complex, CD45 and CD28 at the molecular level, various Fyn/beta-galactosidase fusion proteins were constructed and expressed in Jurkat cells. Co-localization experiments applying antibody-induced co-capping and double immunofluorescence staining techniques were used to study the association of these fusion proteins with the TCR-CD3 complex, CD45 and CD28. Our results revealed that co-localization of Fyn with the TCR-CD3 complex requires the unique N terminus whereas co-localization with CD45 depends on the unique N terminus, the Src homology (SH)3- and a functional SH2 domain. CD28 co-localizes with Fyn molecules that contain the N terminus and a functional SH2 domain. These results suggest that Fyn association with the TCR-CD3 complex, CD45 and CD28 is mediated by different molecular mechanisms.
...
PMID:Co-localization of Fyn with CD3 complex, CD45 or CD28 depends on different mechanisms. 936 21

Immunization with plasmids expressing specific genes (DNA or nucleic acid vaccination (NAV)) elicits robust humoral and cell-mediated immune responses. The mechanisms involved in T cell activation by NAV are incompletely characterized. We have examined the costimulatory requirements of NAV. CD28-deficient mice did not mount Ab or CTL responses following i.m. immunization with eukaryotic expression plasmids encoding the bacterial gene beta-galactosidase (beta gal). Because these mice retained their ability to up-regulate the CTLA4 receptor (a negative regulator of T cell activation), we examined CTLA4's role in the response of wild-type BALB/c mice to NAV. Intact anti-CTLA4 mAb but not Fab fragments suppressed the primary humoral response to pCIA/beta gal without affecting recall responses, indicating CTLA4 activation inhibited Ab production but not T cell priming. Blockade of the ligands for CD28 and CTLA4, CD80 (B7-1) and CD86 (B7-2), revealed distinct and nonoverlapping function. Blockade of CD80 at initial immunization completely abrogated primary and secondary Ab responses, whereas blockade of CD86 suppressed primary but not secondary responses. Simultaneous blockade of CD80 + CD86 was less effective at suppressing Ab responses than either alone. Enhancement of costimulation via coinjection of B7-expressing plasmids augmented CTL responses but not Ab responses, and without evidence of Th1 to Th2 skewing. These findings suggest complex and distinct roles for CD28, CTLA4, CD80, and CD86 in T cell costimulation following nucleic acid vaccination.
...
PMID:Nucleic acid vaccine-induced immune responses require CD28 costimulation and are regulated by CTLA4. 951 Jan 70

CD40 is thought to play a central role in T cell-dependent humoral responses through two distinct mechanisms. CD4+ T helper cells are activated via CD40-dependent Ag presentation in which CD80/CD86 provides costimulation through CD28. In addition, engagement of CD40 on B cells provides a direct pathway for activation of humoral responses. We used a model of adenovirus-mediated gene transfer of beta-galactosidase (lacZ) into murine lung to evaluate the specific CD40-dependent pathways required for humoral immunity at mucosal surfaces of the lung. Animals deficient in CD40L failed to develop T and B cell responses to vector. Activation of Th2 cells, which normally requires CD40-dependent stimulation of APCs, was selectively reconstituted in CD40 ligand-deficient mice by systemic administration of an Ab that is agonistic to CD28. Surprisingly, this resulted in the development of a functional humoral response to vector as evidenced by formation of germinal centers and production of antiadenovirus IgG1 and IgA that neutralized and prevented effective readministration of vector. The CD28-dependent B cell response required CD4+ T cells and was mediated via IL-4. These studies indicate that CD40 signals to the B cells are not necessary for CD4+ Th2 cell-dependent humoral responses to be generated.
...
PMID:Th2-dependent B cell responses in the absence of CD40-CD40 ligand interactions. 1060 18

The effect of local administration of two adenovirus vectors, one of which expressed CTLA4-immunoglobulin (AdCTLA), which blocks the B7-CD28 co-stimulatory pathway of T cell activation in the inflammatory response to adenovirus vectors was investigated. Mice injected with AdCTLA and an E1-deleted adenovirus vector that encodes the lacZ gene (AdRL) into the brain showed inflammatory cell infiltration from the early phase until day 6 after injection that was not different from that seen in control mice injected with an E1-deleted adenovirus vector containing no transgene (Ad0) and AdRL. After day 6 the inflammation in the control mice increased, peaked by day 15 and then decreased gradually but persisted until day 60. By contrast, in mice treated with AdCTLA and AdRL the inflammation, especially T cell infiltration, was suppressed after day 15. The anti-adenovirus antibody titer increased gradually until day 60 in the Ad0-AdRL control group, and whereas the mice injected with AdCTLA and AdRL showed lower anti-adenovirus antibody titers than the control group mice after day 15. Neutralizing antibody was not detected in either group. Expression of beta-galactosidase, the gene product of AdRL, at the injection site in the striatum and corpus callosum peaked on day 6 and remained until day 60 although it was very low in both groups; beta-galactosidase expression was similar in the two groups in spite of the difference in the degree and extent of the local immune response in the brain. This study demonstrated that the injection of an adenovirus vector expressing CTLA4-immunoglobulin into the brain suppressed not only local cell infiltration in the brain but also reduced the humoral immune response to adenovirus vectors.
...
PMID:Local adenovirus-mediated CTLA4-immunoglobulin expression suppresses the immune responses to adenovirus vectors in the brain. 1061 78

Host immune responses limit the duration of expression of transgenes introduced by recombinant adenoviruses, preclude gene transfer upon vector readministration and cause liver injury. CTLA4Ig inhibits immune response by blocking the co-stimulatory interaction between CD28 on T cells and B7 on antigen-presenting cells. We have constructed a recombinant adenovirus, Ad-hUGT1A1-CTLA4Ig that coexpresses human bilirubin-uridinediphosphoglucuronate glucuronosyltransferase (hUGT1A1) and soluble murine CTLA4Ig, both driven by CMV immediate-early promoters. After intravenous injection of this vector (6 x 10(11) p.f.u.) into UGT1A1-deficient jaundiced Gunn rats, serum CTLA4Ig levels peaked at 1.8-2.0 mg/ml on day 7 and declined thereafter to 0.2 mg/ml by day 180. Serum bilirubin declined from mean preinjection levels of 8.0 mg/dl to 0.48-0.6 mg/dl in 3 days, remained normal for 28 weeks, and then gradually increased to 8 mg/dl by day 350. A second injection of Ad-hUGT1A1-CTLA4Ig normalized serum bilirubin. In two rats in this group that were followed longer, serum bilirubin increased to 3.1 and 3.5 mg/dl in 40 weeks, but was normalized again after a third injection. The antibody and cytotoxic lymphocyte (CTL) responses were negligible, and liver biopsy showed no inflammatory cell infiltration. Rats receiving a tertiary challenge with Ad-LacZ (expressing E. coli beta-galactosidase) (5 x 10(11) p.f.u.), 2 months after the second dose of Ad-hUGT1A1-CTLA4Ig, showed beta-galactosidase expression in over 80% of hepatocytes. In contrast, after Ad-hUGT1A1 (which expresses UGT1A1 alone) injection, serum bilirubin remained normal for only 4 weeks, and returned to preinjection levels by day 120. Bilirubin levels did not decline upon reinjection, and beta-galactosidase was not expressed after Ad-LacZ. High levels of adenovirus-specific antibodies and CTL, and hepatic inflammation were found. This is the first demonstration that coexpression of CTLA4Ig permits prolonged expression and repeatable gene transfer by an adenoviral vector.
...
PMID:A non-immunogenic adenoviral vector, coexpressing CTLA4Ig and bilirubin-uridine-diphosphoglucuronateglucuronosyltransferase permits long-term, repeatable transgene expression in the Gunn rat model of Crigler-Najjar syndrome. 1210 28

Collagen Induced Arthritis (CIA) is a widely studied animal model to develop and test novel therapeutic approaches for treating Rheumatoid Arthritis (RA) in humans. Soluble Cytotoxic T-Lymphocyte Antigen 4 (CTLA4-Ig), which binds B7 molecule on antigen presenting cells and blocks CD28 mediated T-lymphocyte activation, has been shown to ameliorate experimental autoimmune diseases such as lupus, diabetes and CIA. Objective of our research was to investigate in vivo the effectiveness of blocking the B7/CD28 T-lymphocyte co-stimulatory pathway, utilizing a gene transfer technology, as a therapeutic strategy against CIA. Replication-deficient adenoviruses encoding a chimeric CTLA4-Ig fusion protein, or beta-galactosidase as control, have been injected intravenously once at arthritis onset. Disease activity has been monitored by the assessment of clinical score, paw thickness and type II collagen (CII) specific cellular and humoral immune responses for 21 days. The adenovirally delivered CTLA4-Ig fusion protein at a dose of 2x10^8 pfu suppressed established CIA, whereas the control beta-galactosidase did not significantly affect the disease course. CII-specific lymphocyte proliferation, IFNgamma production and anti-CII antibodies were significantly reduced by CTLA4-Ig treatment. Our results demonstrate that blockade of the B7/CD28 co-stimulatory pathway by adenovirus-mediated CTLA4-Ig gene transfer is effective in treating established CIA suggesting its potential in treating RA.
...
PMID:[Recombinant adenovirus-mediated gene transfer suppresses experimental arthritis] 1246 78


1 2 Next >>

---