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Results for “Transduction, Genetic”

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At least 19 recordsLinked to original sources
PubMed1995

Antitumor effect induced by granulocyte/macrophage-colony-stimulating factor gene-modified tumor vaccination: comparison of adenovirus- and retrovirus-mediated genetic transduction.

Irradiated tumor cells genetically modified to secrete granulocyte/macrophage-colony-stimulating factor (GM-CSF tumor vaccine) are potent stimulators of systemic antitumor immunity. For the preparation of a GM-CSF gene-modified tumor vaccine, it is important to achieve efficient genetic transduction of tumor cells, leading to an appropriate expression of the induced gene. In this report, with a view to developing a protocol for an effective cancer vaccination therapy, we examined the vaccination efficacies of tumor cells secreting GM-CSF by either adenovirus- or retrovirus-mediated genetic transduction. By using an adenoviral vector, Adex1CAmGMCSF, a highly efficient gene delivery and a high-level expression of the GM-CSF gene were achieved. Unexpectedly, animal vaccination studies showed that the GM-CSF tumor vaccine transduced with the Adex1CAmGMCSF recombinant adenovirus (adenoviral GM-CSF tumor vaccine) was less efficacious than that transduced with the MFGmGMCSF recombinant retrovirus (retroviral GM-CSF tumor vaccine). The GM-CSF serum concentration attained by the adenoviral GM-CSF tumor vaccine was much higher than that obtained by the retroviral GM-CSF tumor vaccine. Our findings indicate that an optimal level of GM-CSF production is important for the tumor vaccine to elicit an adequate response in the host antitumor immunity.

Adenoviridae↗
PubMed2001

Cationic polymer-mediated genetic transduction into cultured human chondrosarcoma-derived HCS-2/8 cells.

The usefulness of three types of cationic polymer, i.e., degraded polyamidoamine (PAMAM) dendrimer (SuperFect Transfection Reagent; Oiagen), linear polyethylenimine (PEI; ExGen 500; Euromedex), and branched PEI in gene delivery into chondrocytes was examined comparatively. A plasmid vector containing the Escherichia coli LacZ (pSES.beta) was combined with one of the three cationic polymers at various molar ratios and the resultant complex (polyplex) was used to transduce a human chondrocyte-like cell line, HCS-2/8. Gene expression was evaluated by an O-nitrophenyl beta-D-galactopyranoside (ONPG) assay and by staining with 0.05% 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-gal; Nacalai Tesque). The ONPG assay showed that the highest delivery rate was achieved when 2microg of pSES.beta was combined with either 21 microg of dendrimer, 1.7microg of linear PEI, or 2.0microg of branched PEI. At the same DNA/polymer ratios, the proportions of X-gal-stained cells were also the highest (31.3 +/- 7.5%, 30.3 +/- 9.0%, and 8.3 +/- 3.1%, respectively). LacZ expression reached the highest level 3 days after the dendrimer-mediated transduction, and gradually declined, returning to the background level on day 14. Possible cytotoxicity was examined by trypan blue staining and phase contrast microscopic observations. Neither cytotoxicity nor morphological change was induced at the optimal dose of each polymer. The cationic polymers, particularly the degraded dendrimer and linear PEI, would be a useful nonviral vector for gene delivery to cells of chondrocytes.

Bone Neoplasms↗
PubMed2002

Successful genetic transduction in vivo into synovium by means of electroporation.

This present study aims at establishing a novel in vivo gene delivery system for intra-articular tissues. Plasmid DNA (pDNA) carrying the firefly luciferase or enhanced green fluorescent protein (EGFP) genes as markers was injected into a joint space and electric stimuli were given percutaneously with a pair of electrodes. Injection with naked pDNA alone did not induce any detectable level of luciferase activity, whereas electroporation at 25-500 V/0.7 cm resulted in a significant expression of the marker gene in the synovium. The expression level depended on the voltage, the optimum transfection being achieved at 150 V/0.7 cm. When the Epstein-Barr virus (EBV)-based plasmid vectors harboring the EBV nuclear antigen 1 (EBNA1) gene and oriP sequence were substituted for conventional pDNA, the transfection efficiency was increased approximately 5-10 times. Histological examination of the EGFP gene-transfected joints revealed that the marker gene was expressed in the synovial membrane while other intra-articular tissues such as articular cartilage were negative for the transgene product. Transgene-specific mRNA was demonstrated in synovium but not in other organs as estimated by RT-PCR analysis. The present results strongly suggest that in vivo electroporation is a quite simple, safe, and effective gene delivery method that could be applicable to gene therapy against articular diseases.

Animals↗
PubMed1962

Genetic transduction with staphylophage.

Korman, Ruth Z. (Elmira College, Elmira, N.Y.) and David T. Berman. Genetic transduction with staphylophage. J. Bacteriol. 84:228-236. 1962.-Transduction by crude lysates obtained by ultraviolet-light induction of phage 53 lysogenic derivatives of Staphylococcus aureus NCTC 8511 has been confirmed. A defined medium and sugar-differential medium were developed, permitting demonstration of transmission of sugar-fermentation loci. The range of transmissible markers has been extended to include free-coagulase production as well as antibiotic-resistance markers. A rare class of heterogeneous streptomycin-resistant transformed clones was obtained. These were assumed to be heterogenotic.

Coagulase↗
PubMed1996

In vivo antitumor effect of cytotoxic T lymphocytes engineered to produce interferon-gamma by adenovirus-mediated genetic transduction.

Immunotherapy with adoptive transfer of genetically-modified cytotoxic T lymphocytes (CTL) is a promising approach for cancer gene therapy. We developed an adoptive therapy model with murine tumor-specific CTL, to which very efficient (up to 100%) gene introduction was achieved by using recombinant adenoviral vectors. Through a comparative study on the antitumor effects of CTL genetically modified with cytokine genes, transduction with interferon-gamma gene resulted in a prominent increase in therapeutic efficacy of CTL in both metastatic and subcutaneous tumor models. Further additive effect was obtained by the adoptive cellular therapy in combination with vaccination of cytokine gene-modified tumor cells. Our findings provide a hopeful strategy of adoptive immunotherapy for human cancers.

Adenoviridae↗
PubMed1973

Marker effects in the genetic transduction of tryptophan mutants of E. coli.

Recombination frequencies have been determined in crosses involving 28 mutant strains for 20 of which the site of the alteration is known from studies of amino-acid substitutions in the protein products. Three of these mutants showed especially high frequencies of recombination when crossed to other single mutants or when crossed to a strain carrying two alterations at opposite ends of the trpA gene. There is no obvious molecular explanation of the high recombination of these three mutants. They include one missense mutant, one amber and one ochre. The low-frequency recombination mutants include all these same classes as well as frameshift mutants. There is nothing unique about the intragenic location of the high-recombination mutants; in each case there is at least one low-recombination mutant in the same codon.-Crosses involving mutants which were isolated in an altered wild type have shown that the behavior of a high-recombination mutant does not result from its molecular configuration alone, but from its combination with the homologous wild-type sequence from the other parent.-Several lines of evidence indicate that recombination in this system frequently involves closely-spaced double exchanges (about 40 codons apart).

Chromosome Mapping↗
PubMed1996

Colocalization of retrovirus and target cells on specific fibronectin fragments increases genetic transduction of mammalian cells.

Hematopoietic cells are important targets for genetic modification with retroviral vectors. Attempts at human gene therapy of stem cells have achieved limited success partly because of low gene transfer efficiency. Chymotryptic fragments of the extracellular matrix molecule fibronectin used during infection have been shown to increase transduction of human hematopoietic progenitor cells. Here, we demonstrate that this enhanced gene transfer into mammalian target cells is due to direct binding of retroviral particles to sequences within the fibronectin molecule. Transduction of mammalian cells, including murine long-term repopulating hematopoietic cells, is greatly enhanced when cells are adherent to chimeric fragments containing these retroviral binding sequences. In addition, colocalization of retrovirus and target cells on fibronectin peptides allows targeted transduction of specific cell types by exploiting unique ligand/receptor interactions.

Animals↗
PubMed2002

Highly efficient genetic transduction of primary human synoviocytes with concentrated retroviral supernatant.

We are developing retroviral-mediated gene transfer to human fibroblast-like synovial cells (FLS) as one approach to characterizing genetic pathways involved in synoviocyte pathophysiology. Prior work has suggested that FLS are relatively refractory to infection by Moloney murine leukemia virus based vectors. To determine if viral titer influenced the transduction efficiency of FLS, we optimized a rapid, efficient, and inexpensive centrifugation method to concentrate recombinant retroviral supernatant. The technique was evaluated by measurement of the expression of a viral enhanced green fluorescent protein transgene in transduced cells, and by analysis of viral RNA in retroviral supernatant. Concentration (100-fold) was achieved by centrifugation of viral supernatant for four hours, with 100% recovery of viral particles. The transduction of FLS increased from approximately 15% with unconcentrated supernatant, to nearly 50% using concentrated supernatant. This protocol will be useful for investigators with applications that require efficient, stable, high level transgene expression in primary FLS.

3T3 Cells↗
PubMedDate not supplied

Drosophila abl and genetic redundancy in signal transduction.

Genetic studies on Drosophila Abl and, more recently, on mouse c-Abl and c-Src indicate that the functions of these non-receptor tyrosine kinases may duplicate activities of other molecules within signal transduction pathways. In Drosophila, second-site mutations have been recovered that disrupt the redundant functions so that the Abl tyrosine kinase is essential to the formation of axonal connections in the embryonic central nervous system and for attachment of embryonic muscles to the body wall. Molecular isolation and analysis of the genes identified by these second-site mutations should define the molecular basis for the genetic redundancy.

Alleles↗
PubMed1995

Genetic approaches to mechanosensory transduction.

Genetic approaches in several organisms provide the means of solving a previously intractable problem: characterizing the molecular foundations of the mechanical senses. In nematode mechanosensory cells, members of a novel class of epithelial ion channel subunits have been implicated as components of a mechanically gated channel. In insect mechanosensory bristles, mutations specifically defective in mechanoreceptor potentials have been identified. And in bacteria, a stretch-activated channel has been molecularly characterized for the first time. Although mechanosensitivity can be a property of an isolated channel, sensory transduction in eukaryotic mechanosensory cells probably requires the interaction of several membrane and cytoskeletal components.

Animals↗
PubMed1975

[Specific and nonspecific factors that influence the transduction of genetic determinants for penicillinase activity and pathogenicity in Staphylococcus aureus. III. The prevention of the transduction of penicillinase determinants by acridine derivatives].

In comparing the antitransducing activity of the acridine derivatives there was revealed a relationship between their chemical structure (the degree of substitution of position 9), the capacity to depress the lytic activity of staphylophages and the action in respect to the transducing particles of the donor lysate.

Acridines↗