PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “VIRUS DISEASES”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20Linked to original sources
PubMed1962

Defined medium for growth of foot-and-mouth disease virus.

Pledger, Richard A. (Plum Island Animal Disease Laboratory, Greenport, N. Y.) and Jerome Polatnick. Defined medium for growth of foot-and-mouth disease virus. J. Bacteriol. 83:579-583. 1962.-Foot-and-mouth disease virus, grown in primary bovine calf-kidney cell layers with a defined medium containing glucose as the only organic substrate, produced virus titers equivalent to those obtained with complex media containing serum and lactalbumin hydrolyzate. Mannose was the only other substrate examined that could replace glucose. Krebscycle intermediates did not or only partially supported viral replication. Phosphate was also found essential for reproduction of foot-and-mouth disease virus. The rate of heat inactivation of foot-and-mouth disease virus in defined medium was more than twice that in complex medium. This, however, did not interfere with the usefulness of the defined medium for short-term biochemical investigations.

Animals↗
PubMed2003

Purification, crystallization and preliminary X-ray analysis of immunogenic virus-like particles formed by infectious bursal disease virus (IBDV) structural protein VP2.

Infectious bursal disease virus (IBDV) causes a highly contagious disease in young chicks and leads to significant economic losses in the poultry industry. VP2 protein, which consists of 452 amino-acid residues, is the primary immunogen of IBDV and contains the epitopes responsible for eliciting neutralizing antibodies. When the chimeric VP2 protein (rVP2H) of a local IBDV strain P3009 was expressed alone using the baculovirus system, virus-like particles of approximately 23 nm in diameter formed spontaneously. Highly pure rVP2H particles, obtained using ammonium sulfate precipitation, immobilized metal-ion affinity chromatography and gel-filtration chromatography, were successfully crystallized using the vapour-diffusion method. These crystals, with a maximum dimension of 0.4 mm, diffracted X-rays to 4.5 A resolution, but data were only collected to 6 A. Preliminary analysis of the diffraction data showed that the rVP2H crystals belong to the cubic space group P2(1)3, with unit-cell parameter 323.1 A. The icosahedral symmetry of the particles is clearly seen in the self-rotation function maps, with dyads and triads coincident with the crystallographic axes. Each asymmetric unit contains 1/3 of the particle, or 20 rVP2H subunits, and there are four particles in a unit cell, probably in a tetrahedral arrangement.

Baculoviridae↗
PubMed2000

[A recombinant fowlpox virus expressing the fusion protein of Newcastle disease virus strain F48E8 and its protective efficacy].

The transfer vector pFGF1175-1 was constructed by insertion the fusion protein gene of Newcastle disease virus (NDV) F48E8 strain into the insertion vector pFG1175-1, downstream of P7.5 promotor, and then transfected chicken embryo fibroblast (CEF) cell cultures which had been infected with fowlpox virus (FPV) Chinese vaccine strain 282E4 for 3-4 hours. Recombinant FPV with blue plaques were selected and purified in CEF cell culture laid agar containing X-gal. The recombinant FPV named rFPV-NDF was confirmed expressing NDV fusion protein by indirect immunofluorescence assay, and could protect chickens against virulent NDV challenge, The protective rate was 96.7%.

Animals↗
PubMed1983

Interferon induction by viruses. X. A model for interferon induction by Newcastle disease virus.

Unirradiated Newcastle disease virus (NDV, strain AV) induced high levels of interferon (IFN) in primary chick embryo cells if the cells were 'aged' in vitro for 6 to 7 days. Dose (multiplicity)-response (IFN yield) curves, carried out in the presence of anti-NDV serum to prevent cycling infection, revealed that stocks of NDV-AV contain about sevenfold more IFN-inducing particles (IFP) than infectious particles (PFP). These non-infectious IFP were responsible for nearly all IFN induction in 'aged' cells, since PFP were determined to be incapable of inducing IFN. In contrast, with mouse L(Y) cells as hosts, about one-third the number of particles as there are PFP appeared to score as IFP. Heat and u.v. radiation (254 nm) inactivated NDV IFP and PFP activity at the same rate whether tested in chick or mouse cells, implying that virion-associated transcription is required to induce IFN. A model is proposed to account for the generation of IFN-inducing particles from infectious NDV following u.v. irradiation, and their subsequent inactivation at high doses of radiation. The model defines a series of u.v. targets in the NDV genome that regulate the expression of IFN-inducing particle activity in 'unaged' chick embryo cells.

Animals↗
PubMed1997

Interference activity of bovine herpes virus 1 strains against Aujeszky's disease virus in cell cultures.

The interference-inducing activity of different low- and high-virulence strains of bovine herpes virus 1 (BHV-1) against Aujeszky's disease virus was studied by a parallel titration on permissive and non-permissive cell culture. The low-virulence BHV-1 strains possessed better interference-inducing activity than the high-virulence strains. An interference blocking test (IBT) was developed for the detection of BHV-1 antibodies in bovine sera. Comparative results of IBT and the virus neutralisation reaction did not show statistically reliable differences.

Animals↗
PubMedDate not supplied

A method to rapidly convert Newcastle disease virus and infectious bronchitis virus ImmunoComb scores into conventional hemagglutination-inhibition titers.

ImmunoComb scores are highly correlated to hemagglutination-inhibition (HI) titers against infectious bronchitis virus and Newcastle disease virus. Statistical calculations permit using an individual COMBSCORE to predict the corresponding HI titer value. Tables are presented to facilitate the transformation of COMBSCORES into HI titers.

Antibodies, Viral↗
PubMedDate not supplied

Transmissibility of Australian strains of Newcastle disease virus.

The transmission of Newcastle disease virus strains from infected to direct-, indirect-, and aerosol-contact groups of chickens was studied. Chickens 7, 21, and 63 days old were used in separate trials. Chicken age and virus strain were found to be important in spread of the virus. Strain V4 spread quickly to all contact groups and was classed as highly transmissible, whereas strain JA failed to infect all contact chickens of each age group, thus spreading less efficiently than strain V4. The viruses spread more readily among the 2 older groups. The significance of the transmissibility of Newcastle disease virus vaccine is briefly discussed.

Age Factors↗
PubMed1998

Virus-specific CD4+ T cells eliminate borna disease virus from the brain via induction of cytotoxic CD8+ T cells.

Persistent Borna disease virus infection of the brain can be prevented by treatment of naive rats with a virus-specific CD4+ T-cell line prior to infection. In rats receiving this treatment, only a transient low-level encephalitis was seen compared to an increasingly inflammatory reaction in untreated infected control rats. Virus replication was found in the brain for several days after infection before the virus was cleared from the central nervous system. The loss of infectivity from the brain was confirmed by negative results by reverse transcription-PCR with primers for mRNA, by in situ hybridization for both genomic and mRNA, and by immunohistology. Most importantly, in vitro assays revealed that the T-cell line used for transfusion had no cytotoxic capacity. The kinetics of virus clearance were paralleled by the appearance of CD8+ T cells and the expression of perforin in the brain. Testing of lymphocytes isolated from the brains of CD4+ T-cell-treated rats after challenge revealed high cytotoxic activity due to the presence of CD8+ cytotoxic T cells at time points when brain lymphocytes from infected control rats induced low-level cytolysis of target cells. Neutralizing antiviral antibodies and gamma interferon were shown not to be involved in the elimination of virus from the brain.

Animals↗
PubMedDate not supplied

Embryo vaccination of specific-pathogen-free chickens with infectious bursal disease virus: tissue distribution of the vaccine virus and protection of hatched chickens against disease.

Vaccination of specific-pathogen-free chickens as 18-day embryos with the BVM isolate of infectious bursal disease virus (IBDV) resulted in extensive replication of the vaccine virus in the embryonic tissues. The virus was recovered from lung, thymus, proventriculus, liver, kidney, and spleen of embryos 1 day postvaccination, and recoverable virus persisted for at least 7 days. Replication and spread of the vaccine virus in chickens vaccinated as 18-day embryos was compared with that in chickens vaccinated at hatch. Distribution of the virus in tissues was more extensive, virus levels in tissues were generally higher, and detectable virus persisted longer in chickens vaccinated as 18-day embryos than in those vaccinated at hatch. Effective vaccine response could be initiated with 6.2 median embryo lethal doses, the lowest dose tested. Chickens immunized as embryos developed neutralizing antibody against IBDV and resisted challenge with pathogenic IBDV at 4, 6, 8, and 10 weeks of age.

Animals↗
PubMed1978

The isolation of lentogenic strains of Newcastle disease virus in Australia.

Twelve isolations of Newcastle disease virus were made from 77 clinical samples from chickens from conjunctivitis, respiratory disease, proventriculitis and bursal atrophy. Nine of the isolations were made from chickens with conjunctivitis. The viruses were identified as Newcastle disease virus by inhibition of their haemagglutinins with specific antiserum to Newcastle disease virus. The viruses failed to kill chicken embryos after inoculation into the allantoic cavity and they were judged to be lentogenic strains. There was no evidence that the Newcastle disease viruses were responsible for any of the clinical conditions from which they were isolated. The presence of other agents in 10 of the samples was indicated by reduced production of haemagglutinin in allantoic fluids of infected embryos, by deaths of infected embryos, by the production of cytopathic changes in avian cell cultures and by electron microscopy. Three isolations of infectious bronchitis virus, 2 of avian adenovirus and one of avian reovirus were made. Other samples were suspected of containing infectious bronchitis virus and mycoplasmas, but these were not isolated. The Newcastle disease viruses failed to produce plaques in chicken embryo fibroblast cell cultures and they were separated from the contaminating agents by haemagglutination and elution followed by passage at terminal dilution in chick embryos. No Newcastle disease virus was isolated from 60 caecal tonsils and 60 lung samples from 9-week-old broiler chickens. Eight lung samples yielded mycoplasmas that caused haemadsorption in chicken cell cultures. The mycoplasmas were probably Mycoplasma gallisepticum.

Animals↗
PubMed1975

Infective and noninfective hemagglutinating particles of Newcastle disease virus: biological and chemical characterization.

Newcastle disease virus (Herts strain), grown in embryonated eggs or in a line of bovine kidney cells, was purified and then separated by sucrose density gradient centrifugation into infectious (IH) and noninfectious hemagglutinating (NIH) particles. These particles were morphologically similar, although the average size of IH was twice that of NIH particles. The activity of hemagglutinin per milligram of virus protein was two- to threefold higher in NIH particles than in IH particles, whereas the specific activity of neuraminidase did not differ in the two particle types. This was consistent with the observed particle size difference. The distribution of the major proteins in IH and NIH particles from egg-grown virus, determined by polyacrylamide gel electrophoresis (PAGE), was significantly different. In IH particles the molar ratio of protein 1 (74,000 daltons) to proteins 2 and 3 (56,000 daltons): protein 6 (41,000 daltons) was 1.0:2.5:2.5; in NIH particles the ratio was 1.0:0.6:1.0. When Newcastle disease virus was grown in bovine kidney cells, the molar ratio of proteins in IH particles resembled that of of egg-grown virus. However, in NIH particles from bovine kidney cells, only protein bands corresponding to protein 1 and proteins 2-3 were present and their molar ratio was 1.0:0.6. Protein 6 was marginally detectable in these particles. Analysis of the proteins in [3H]isoleucine- and [14C]glucosamine-labeled virus showed proteins 1 and 2 (glycoproteins) present in the ratio of 1.0:0.5; protein 3, the nucleoprotein, was not detected. These results are compatible with previous findings by others that NIH particles are deficient in RNA and nucleoprotein antigen, and suggest that formation of discrete particles of Newcastle disease virus by budding requires at most minimal amounts of proteins 3 or 6. The fatty acid composition of egg-grown IH and NIH particles was not significantly different and resembled that of normal allantoic fluid.

Cell Line↗
PubMed1962

An apparently new lethal virus disease of infant mice.

A hitherto unreported disease of infant mice is described. The agent reproduces upon passage, is filterable, is confined mainly to the gastrointestinal tract in infant and adult mice, causes death in infants and inapparent infection in adults, and is sensitive to mild heat, ether, and sodium deoxycholate. Unique and characteristic morphologic changes occur in the epithelial cells of the intestine in infected infant mice. These consist in the development of multinucleated giant cells designated "balloon cells.".

Animals↗