The safety and longevity of DNA vaccines for fish. (65/7076)

A plasmid that contained the cytomegalovirus (CMV)-promoter-driven lacZ reporter gene (pCMV-lacZ) remained in the epaxial muscle of five of eight goldfish as covalently closed circles, the most functional form of plasmid, for at least 70 days at 22 degrees. It was not present in the gills or elsewhere by polymerase chain reaction and was not integrated. Its expressed protein, Escherichia coli beta-galactosidase (beta-gal), which was in the injected myofibres, was detected in all the fish at 4-21 days and in about half the fish from 28 days until the end of the experiment at 70 days. The numbers of cells that secreted antibody to beta-gal in the kidney peaked at 14 days. Serum antibody and proliferating kidney cells to beta-gal were in all fish from 14 days with a plateau of the responses from 21 days onwards. The plasmid did not induce autoimmune-like antibodies to itself or to single- or double-stranded salmon testis DNA. Plasmids can therefore induce long-term foreign protein expression whilst inducing humoral and cell-mediated immunity without autoimmunity or integration in goldfish.  (+info)

Mammalian granulocyte-macrophage colony-stimulating factor and some CpG motifs have an effect on the immunogenicity of DNA and subunit vaccines in fish. (66/7076)

A eukaryotic plasmid DNA carrying the AACGTT CpG motif in its ampR gene is a 'danger' signal for mice and caused an increase in the specific antibody titres of fish and mice after immunization with beta-galactosidase (beta-gal). A second pUC-based plasmid, which is inactive in mice and contains the GACGTC CpG motif in its cytomegalovirus (CMV) promoter, had no effect on antibody responses to beta-gal in either fish or mice. A synthetic oligonucleotide, which contains the GACGTT motif, potentiated antibody responses to co-administered beta-gal protein in mice, but not in fish. This is early evidence that lower and higher vertebrates recognize different unmethylated CpG motifs as 'danger' signals. In addition, plasmid DNA expressing mouse granulocyte-macrophage colony-stimulating factor (GM-CSF) had a marked effect on cytotoxic T-cell-like activity in fish by reducing the average number of myofibres that expressed beta-gal, 28 days after co-injection with plasmid DNA expressing beta-gal. Although the mechanism by which the mouse GM-CSF exerted its biological effects in fish is unknown, this finding might have important implications for fish vaccination, particularly when cytotoxic T cells may play a critical role.  (+info)

Immunohistochemical analysis, human papillomavirus DNA detection, hormonal manipulation, and exogenous gene expression of normal and dysplastic human cervical epithelium in severe combined immunodeficiency mice. (67/7076)

The cervical squamocolumnar junction of normal and dysplastic human xenografts was maintained in SCID-beige mice. Dysplastic tissue maintained a dysplastic morphology, irregular pattern of keratin expression, elevated levels of cellular proliferation, and human papillomavirus type 16 and/or type 18 DNA. Hyperplastic changes of normal xenografts occurred via high-dose estrogen exposure, and through recombinant adenovirus infection, the introduction and stable expression of an exogenous gene was accomplished.  (+info)

A novel gene delivery system targeting cells expressing VEGF receptors. (68/7076)

Two ligand oligopeptides GV1 and GV2 were designed according to the putative binding region of VEGF to its receptors. GV1, GV2 and endosome releasing oligopeptide HA20 were conjugated with poly-L-lysine or protamine and the resulting conjugates could interact with DNA in a noncovalent bond to form a complex. Using pSV2-beta-galactosidase as a reporter gene, it has been demonstrated that exogenous gene was transferred into bovine aortic arch-derived endothelial cells (ABAE) and human malignant melanoma cell lines (A375) in vitro. In vivo experiments, exogenous gene was transferred into tumor vascular endothelial cells and tumor cells of subcutaneously transplanted human colon cancer LOVO, human malignant melanoma A375 and human hepatoma graft in nude mice. This system could also target gene to intrahepatically transplanted human hepatoma injected via portal vein in nude mice. These results are correlated with the relevant receptors (flt-1, flk-1/KDR) expression on the targeted cells and tissues.  (+info)

Alterations in protein expression caused by the hha mutation in Escherichia coli: influence of growth medium osmolarity. (69/7076)

The Hha protein belongs to a new family of regulators involved in the environmental regulation of virulence factors. The aim of this work was to study the effect of the hha mutation on the overall protein pattern of Escherichia coli cells by two-dimensional polyacrylamide gel electrophoresis. The growth medium osmolarity clearly influenced the effect of the hha mutation. The number of proteins whose expression was altered in hha cells, compared with wild-type cells, was three times larger at a high osmolarity than at a low osmolarity. Among the proteins whose expression was modified by the hha allele, both OmpA and protein IIAGlc of the phosphotransferase system could be identified. As this latter enzyme participates in the regulation of the synthesis of cyclic AMP and hence influences the catabolite repression system, we tested whether the expression of the lacZ gene was also modified in hha mutants. This was the case, suggesting that at least some of the pleiotropic effects of the hha mutation could be caused by its effect on the catabolite repression system.  (+info)

Regulation of beta-galactosidase expression in Bacillus megaterium DSM319 by a XylS/AraC-type transcriptional activator. (70/7076)

The beta-galactosidase-encoding bgaM gene of Bacillus megaterium DSM319 and the divergently orientated bgaR operon were isolated and sequenced. Both traits are subject to catabolite repression. A set of single-gene replacement mutants was generated and used to analyze gene function. BgaR was found to be a XylS/AraC-type positive transcriptional regulator of bgaM; a potential regulator binding site overlaps the bgaM promoter. A mechanism for regulation of beta-galactosidase expression in B. megaterium is proposed.  (+info)

Characterization of MarR superrepressor mutants. (71/7076)

MarR negatively regulates expression of the multiple antibiotic resistance (mar) locus in Escherichia coli. Superrepressor mutants, generated in order to study regions of MarR required for function, exhibited altered inducer recognition properties in whole cells and increased DNA binding to marO in vitro. Mutations occurred in three areas of the relatively small MarR protein (144 amino acids). It is surmised that superrepression results from increased DNA binding activities of these mutant proteins.  (+info)

Efficient gene delivery to the inflamed colon by local administration of recombinant adenoviruses with normal or modified fibre structure. (72/7076)

BACKGROUND/AIMS: Replication deficient recombinant adenoviruses represent an efficient means of transferring genes in vivo into a wide variety of dividing and quiescent cells from many different organs. Although the gastrointestinal tract is a potentially attractive target for gene therapy approaches, only a few studies on the use of viral gene transfer vehicles in the gut have been reported. The prospects of using recombinant adenoviruses for gene delivery into epithelial and subepithelial cells of the normal and inflamed colon are here analysed. METHODS: An E1/E3 deleted recombinant adenovirus (denoted AdCMVbetaGal) and an adenovirus with modified fibre structure (denoted AdZ.F(pk7)) both expressing the bacterial lacZ gene under the control of a human cytomegalovirus promoter were used for reporter gene expression in vitro and in vivo. beta-Galactosidase activity was determined by specific chemiluminescent reporter gene assay. RESULTS: Intravenous or intraperitoneal injection of AdCMVbetaGal into healthy Balb/c mice caused strong reporter gene expression in the liver and spleen but not in the colon. In contrast, local administration of AdCMVbetaGal resulted in high reporter gene expression in colonic epithelial cells and lamina propria mononuclear cells. A local route of adenovirus administration in mice with experimental colitis induced by the hapten reagent trinitrobenzenesulphonic acid was next evaluated. Interestingly, rectal administration of AdCMVbetaGal caused a higher beta-galactosidase activity in isolated lamina propria cells from infected mice with experimental colitis than in those from controls. Furthermore, isolated lamina propria cells from mice with colitis infected in vitro showed a significant increase in reporter gene activity compared with controls. Finally, AdZ.F(pk7) adenoviruses with modified fibre structure produced 10- to 40-fold higher reporter gene activity in spleen T cells and lamina propria mononuclear cells of colitic mice compared with standard AdCMVbetaGal vectors. CONCLUSIONS: Local administration of recombinant adenoviruses with normal or modified fibre structure could provide a new reliable method for targeted gene expression in the inflamed colon. Such gene delivery could be used to specifically express signal transduction proteins with therapeutic potential in inflamed colonic tissue. In particular, adenoviruses with modified fibre structure may be useful in T cell directed therapies in intestinal inflammation.  (+info)