PubMed Health⌕ Search

Biomedical subjects

B Gutter

Publications and source records attributed to B Gutter.

At least 19 recordsLinked to original sources
PubMed2006

B subunit of E. coli enterotoxin as adjuvant and carrier in oral and skin vaccination.

Mucosal sites are one of the main natural ports of entry into the body. Stimulation of a local response by antibodies as the systemic protection may enhance the efficacy of non-living vaccines, and allow for vaccination by subunit vaccines without the need for injection. Mucosal or skin vaccination necessitates a suitable adjuvant and carrier. Escherichia coli heat-labile enterotoxin (LT) and its B subunit (LTB) have been found to be effective adjuvants. The aim of this study was to efficiently produce and purify recombinant LTB (brLTB), and examine its adjuvant and carrier properties. The gene encoding LTB was cloned and expressed in E. coli, and the product was found to have a pentameric form with the ability to bind the cell receptor, GM1 ganglioside. A one-step method for efficient purification and concentration of brLTB was developed. Both oral and intramuscular vaccination with purified brLTB yielded high antibody titers, which detected the whole toxin. In an attempt to test its adjuvant characteristics, brLTB was mixed with either BSA or a recombinant protein (rKnob of egg drop syndrome adenovirus) and delivered intramuscularly, orally or transcutaneously. The addition of brLTB significantly elevated the antibody response in groups vaccinated orally and transcutaneously, but had no influence in injected groups. Vaccination with another recombinant protein, (viral protein 2 of infectious bursal disease virus) supplemented with brLTB did not elevate the antibody response, as compared to vaccination with the antigen alone. These results demonstrate that the addition of brLTB makes oral and transcutaneous vaccination with protein antigens possible.

Adenoviridae Infections↗
PubMed2005

A subunit vaccine against hemorrhagic enteritis adenovirus.

Hemorrhagic enteritis virus (HEV) is an adenovirus that infects turkeys and causes immunosuppression and mortality. The virus used for the inactivated vaccine is extracted from spleens of infected turkeys, since its propagation in tissue cultures or embryonated eggs is unsuitable for mass production. The aim of this study was to develop a subunit vaccine based on a capsid protein of the virus. The knob protein, together with an adjacent part of the shaft domain pertaining to the fiber protein of HEV, was expressed in Escherichia coli and tested as a vaccine. Vaccination with this recombinant protein conferred protection against challenge in controlled and in floor-pen experiments. This finding suggests that the knob protein may be used as safe and efficient vaccine against hemorrhagic enteritis of turkeys. The possibility that the knob proteins of other adenoviruses may be protective and serve as vaccine is also discussed.

Adenoviridae Infections↗
PubMed2005

Vaccine and adjuvant activity of recombinant subunit B of E. coli enterotoxin produced in yeast.

Escherichia coli heat-labile enterotoxin (LT) and cholera toxin (CT) have been studied intensively as vaccines against diseases caused by those bacteria and as adjuvants for mucosal vaccination. Two major problems interfere with the use of these promising adjuvants: their toxicity and the residual bacterial endotoxins mixed with the desired LT. In this study, subunit B of LT was expressed in Pichia pastoris yeast cells (yrLTB) and the recombinant protein was purified and concentrated by ion-exchange chromatography. The final yield of the recombinant protein was 5-8 mg/l induction medium. The molecule is in pentameric form and binds to GM1 gangliosides. When given orally to chickens, anti-LTB antibodies were produced, exhibiting its ability to cross the digestive system and induce an immune response. The adjuvant activity of yrLTB was proven by fusing it to viral protein 2 (VP2) of infectious bursal disease virus. Birds intramuscularly vaccinated with this molecule exhibit 70-100% protection, in a dose-response-dependent manner. This method eliminated the bacterial endotoxins and enabled the production of large quantities of LTB. Expression in a eukaryotic system allows the production of fusion proteins that require post-translational modifications. This may allow oral vaccination with a protein fused to yrLTB. The approach described in this study will enable the efficient production of a non-toxic, eukaryotically expressed enterotoxin as a vaccine against the toxin itself or as a carrier or adjuvant for foreign vaccine molecules.

Adjuvants, Immunologic↗
PubMed2003

A subunit vaccine against the adenovirus egg-drop syndrome using part of its fiber protein.

In this study, the effectiveness of antibodies against the hexon, fiber or a fiber fragment of an avian adenovirus egg-drop syndrome (EDS), in neutralizing the virus was tested. The fiber protein is responsible for binding the virus to the target cell. The fiber fragment knob-s comprises the carboxy-terminal knob domain and 34 amino acids of the immediately adjacent shaft domain of the adenovirus fiber protein. The hexon, fiber capsid protein and knob-s were produced in E. coli and injected into chickens. Antibodies that were produced against the whole fiber protein showed some hemagglutination inhibition (HI) activity. Antibodies produced against the knob-s protein showed HI activity and serum neutralization (SN) activity similar to the positive control-whole virus vaccine. We assume that production of only part of the fiber enables the protein produced in E. coli to fold correctly. Antibodies produced against the hexon protein showed no SN activity. In summary, knob-s induced SN and HI antibodies against EDS virus at a rate similar to the whole virus and were significantly more efficient than the full-length fiber. The recombinant knob-s protein may be used as a vaccine against pathogenic adenovirus infections.

Adenoviridae Infections↗
PubMed2001

Immune response and resistance to infectious bursal disease virus of chicken lines selected for high or low antibody response to Escherichia coli.

Two experimental broiler lines were developed by divergent selection for high (HH) and low (LL) antibody response to Escherichia coli. Antibody response of these lines to immunization with a commercial vaccine (whole inactivated virus, WIV) against infectious bursal disease virus (IBDV) or with proteins VP2 and VP3 of that virus, and their resistance to challenge with a virulent IBDV, were tested. The study was performed with 213 male and female chicks from the tenth generation of the HH and LL lines. At 15 d of age, after disappearance of maternal antibodies, chicks from each line were randomly divided into four groups and injected with WIV, VP2, VP3, or adjuvant alone as a negative control. Chicks were bled 18 d postinjection, and antibody titers were determined by ELISA. Ten days later, the chicks were challenged with a virulent strain of the virus and killed after 10 d; the ratio of bursa of Fabricius to 100 g BW was determined for each bird. Significant differences in antibody titers were found among immunized and control chicks. Chicks from the HH line exhibited significantly higher antibody titers than LL chicks in response to WIV and VP2 vaccines but not to VP3 vaccine. Following challenge, bursa weight (relative to BW) of HH and LL chicks vaccinated with WIV and VP2 was significantly higher (P < 0.01) than that of chicks vaccinated with VP3 or the challenged unvaccinated control. No difference was found in this parameter between the latter two groups. Possible explanations for the differences in the line response to VP2 and VP3 are discussed.

Animals↗
PubMed1999

Day-old vaccination with live-in-oil vaccines: Newcastle disease (ND) and infectious bursal disease (IBD) in chicks and ND in turkey poults.

One-day-old broiler chicks were vaccinated with live Newcastle disease (ND) vaccine incorporated in oil alone or in killed-in-oil ND vaccine. Incorporation of live vaccine in oil emulsions was carried out just prior to vaccination. Live-in-oil ND vaccine containing 106.0 median embryo lethal doses (ELD50/dose induced the same protection following challenge and the same level of antibody at 42 days post-vaccination as did commercial killed-in-oil ND vaccine containing about 250 times as much antigen (108.4 ELD50/dose). Incorporation of live ND vaccine in killed-in-oil vaccine contributed markedly to protection rates and antibody levels, as compared to those obtained following vaccination with killed-in-oil vaccine only. One-day-old turkey poults also showed the advantage of incorporation of live ND vaccine in killed-in-oil vaccine when challenged 3 months post-vaccination. One-day-old broiler chicks, vaccinated with live ND and infectious bursal disease vaccine (IBD) incorporated in killed-in-oil combined ND + IBD vaccine, showed better protection against challenge with IBDV and higher antibody levels to NDV as compared to vaccination with killed-in-oil vaccine alone.

Journal Article↗
PubMed1998

The complete DNA sequence and genome organization of the avian adenovirus, hemorrhagic enteritis virus.

Hemorrhagic enteritis virus (HEV) belongs to the Adenoviridae family, a subgroup of adenoviruses (Ads) that infect avian species. In this article, the complete DNA sequence and the genome organization of the virus are described. The full-length of the genome was found to be 26,263 bp, shorter than the DNA of any other Ad described so far. The G + C content of the genome is 34.93%. There are short terminal repeats (39 bp), as described for other Ads. Genes were identified by comparison of the DNA and predicted amino acid sequences with published sequences of other Ads. The organization of the genome in respect to late genes (52K, IIIa, penton base, core protein, hexon, endopeptidase, 100K, pVIII, and fiber), early region 2 genes (polymerase, terminal protein, and DNA binding protein), and intermediate gene IVa2 was found to be similar to that of other human and avian Ad genomes. No sequences similar to E1 and E4 regions were found. Very low similarity to ovine E3 region was found. Open reading frames were identified with no similarity to any published Ad sequence.

Adenoviridae↗
PubMed1979

Herpes simplex virus DNA polymerase, thymidine kinase and deoxyribonuclease activities in cells infected with wild type, ultraviolet-irradiated and defective virus.

The DNA polymerase, thymidine kinase and deoxyribonuclease activities were studied in cells infected with wild type (wt), ultraviolet (UV)-irradiated and defective herpes simplex virus type 1. All three enzymatic activities were expressed in cells infected with wt virus. In cells infected with UV-irradiated virus, the thymidine kinase and deoxyribonuclease activities were inhibited and the DNA polymerase activity was markedly suppressed. In cells producing defective virus, there was thymidine kinase activity, but the viral deoxyribonuclease activity was considerably reduced. The DNA polymerase activity was fully expressed in cells producing defective virus at passage level 5, but at passage level 6, the activity of the viral DNA polymerase declined.

Animals↗
PubMed1977

The photodynamic modification of DNA by hematoporphyrin.

Illumination (white light: 300-750 nm) of DNA in the presence of hematoporphyrin (less than or equal to 5-10 (-4) M) results in selective degradation of the guanine moiety. DNA so illuminated exhibits physical chemical properties (lowered sedimentation coefficients, lower temperatures of helix-coil transitions, increased buoyant density values) consistent with single-chain scissions (and the generation of single-stranded regions) which presumably are secondary to the photodegradation of the guanine residue. Illumination of DNA in the presence of low levels of hematoporphyrin (greater than or equal to 2.5 - 10 (-4) M) results in a biopolymer exhibiting all of the physical properties described above with the exception of a lowered sedimentation coefficient; on the contrary such DNA is aggregated. Of the four usual deoxynucleosides irradiated in the presence of hematoporphyrin, only deoxyguanosine is destroyed.

Binding Sites↗
PubMed1977

A study of the photoinduced mutagenicity of methylene blue.

Illumination of Salmonella typhimurium strains in the presence of methylene blue resulted in the production of mutations of the base-substitution type. This photodynamic effect mediated by the dye was separable from the genetic event seen when bacteria are illuminated in the absence of added photosensitizers.

Light↗
PubMed1976

Mutagenicity and DNA-modifying activity: a comparison of two microbial assays.

Aspects of the Salmonella mutagenesis and Escherichia coli DNA polymerase deficient (pol A1) assay procedures for detecting environmental mutagens are discussed. The chief limitation of the pol A1-- assay involves substances that do not diffuse rapidly in agar. This problem can be overcome by performing the test in suspension. A simple procedure for accomplishing this is described. Although the Salmonella assay is more flexible, under routine conditions it does not respond to several classes of substances which give positive responses in the pol A1- system. For optimal testing, it is recommended that the two microbial assays be used in tandem. The DNA-modifying properties of povidone-iodine for eukaryotic and prokaryotic cells are described. Even though this substance does not display mutagenic properties in the standard Salmonella assay, it does so in suspension culture. The basis of the mutagenic and DNA-modifying properties of povidone-iodine appears to involve the iodination of the cystosine residue of DNA.

Cells, Cultured↗
PubMed1973

Studies on the developmental cycle of Chlamydia trachomatis: selective inhibition by hydroxyurea.

Hydroxyurea, a potent inhibitor of deoxyribonucleic acid synthesis, inhibits the development of trachoma agent when applied at a concentration of 5 x 10(-2) M. At a lower concentration, 5 x 10(-4) M, hydroxyurea permits the development of the trachoma inclusion bodies and initial bodies, but arrests the formation of elementary bodies, the infectious entity of the agent. The inhibitory effect of 5 x 10(-4) M hydroxyurea is reversible and can be used to synchronize the development of the agent. The synthesis of deoxyribonucleic acid, ribonucleic acid, and proteins takes place in the initial bodies after the removal of the inhibitor.

Amino Acids↗