Evidence of the existence of incomplete Newcastle disease virus.
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A total of fifty birds of a four-line hybrid (Plymouth X Cornish) were used in an experiment to elucidate the link between the dynamics of serum sialic acid and the level of antihemagglutinins prior to and after vaccination against Newcastle disease (ND). It was found that immediately after vaccination the level of serum sialic acid rose essentially, and persisted at high values in the course of 7-8 days. It came back to the initial level at the time when the ND antihemagglutinins showed a maximum rise, i. e., when the active immunopoietic process was over. It is concluded that the changes in the serum sialic acid may be used tentatively as an adjunct in the evaluation of the immune responsiveness of the animal organism in the course of immunopoiesis following active immunization.
Chickens of 7 weeks or 20 weeks of age were divided into three groups according to their antibody status (high, low, absent) and were infected with a velogenic viscerotropic Newcastle disease virus. To follow patterns of viral replication, birds were necropsied at regular intervals up to 22 days and organs were sampled from each bird. In non-immune birds, virus could be isolated from all organs examined. In birds with antibody, virus was most frequently isolated from the proventriculus, cecal tonsil, bursa, and brain. However, because no one organ could be recommended for all situations, all four should be sampled for field diagnosis. In immune birds, although clinical signs were either mild or absent, widespread virus replication occurred up to 19 days post-challenge.
We have found that in cultured mouse bone-marrow-derived macrophages (BMDM), endogenous IFN-beta specifically regulates Newcastle disease virus (NDV) induced interferon (IFN)-alpha/beta synthesis, possibly by influencing the activity of genes within the regulatory locus If-1. Comparison of anti-IFN-beta-treated BMDM from C57BL/6 mice and the congenic line B.6C-H28c carrying the high (h) or low (l) producer allele of If-1, respectively, revealed a much stronger response of the If-1l allele to exogenous IFN-alpha treatment. Twenty IU rIFN-alpha 4 were sufficient to induce nearly complete suppression of NDV-induced IFN-alpha and IFN-beta production in BMDM from B6.C-H28c mice, but had no effect on the IFN-alpha/beta response induced by Sendai virus, another member of the paramyxovirus group. Simultaneous treatment of BMDM with cycloheximide inhibited the suppressive effect of rIFN-alpha 4, indicating that IFN induced the expression of one or several new proteins encoded by gene(s) within the If-1l locus which are responsible for the NDV-specific downregulation of IFN-alpha/beta production. A time course analysis indicated that the suppressive activity of IFN-induced If-1l gene products took 12 h to develop. It was preceded by an opposite priming effect, leading to enhancement of the early IFN-alpha/beta response to NDV measured 5 h after infection. This priming effect in BMDM was, however, only visible during an 8-h period of IFN-alpha treatment, whereas in the continued presence of IFN for 12 h or longer, priming was superimposed by the inhibitory action of the If-1l gene products.(ABSTRACT TRUNCATED AT 250 WORDS)
Seven hundred and ten blood samples were collected at random from commercial layers in Tamil Nadu on Whatman filter paper No. 1 instead of the conventional method of serum collection. The birds were subjected to different Newcastle disease (ND) vaccination schedules and samples were collected to study the vaccinal response to ND at field level. Eluates were obtained from sample areas of filter paper using Brij-35 solution [detergent] and subjected to the micro haemagglutination inhibition (HI) test for ND antibodies. The HI titre ranged from less than 2(4) to 2(9). The possible causes of poor immune response to ND vaccinations are discussed.
The envelope proteins of Newcastle-disease virus were preferentially labelled when a suspension of virus particles that contained the photoreactive probe 12-(4-azido-2-nitro-phenoxy)stearoyl[1-14C]glucosamine was irradiated. One of the proteins labelled was not readily accessible to surface labelling with 125I.
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Newcastle disease virus (NDV)-induced damage to the embryonic chicken trachea, the tracheal explants, and red blood cells (RBCs) was studied by scanning electron microscopy. In the tracheae, NDV caused deciliation and depletion of the epithelial cells. In the tracheal explants, the same pathologic changes could be seen within 6 hr of virus infection. In RBCs, a perforation and a change in surface morphology were observed.
In order to study the aerosol transmission of arthropathic and amyloidogenic Enterococcus faecalis strains, preliminary aerosol experiments were performed. The experiments were carried out in empty isolators to assess the yield and viability of E. faecalis and Newcastle disease vaccine virus (NDVV) aerosol particles with time. NDVV was aerosolized because this virus would be used in combination with E. faecalis in a subsequent study. Concentrations of about 10(5) colony-forming units (CFU) of E. faecalis/ml of air were still found 30 min after the aerosol application. At 45 min, however, E. faecalis concentrations dropped below the detection level. The average E. faecalis concentration during the aerosol experiment was estimated at 10(5) CFU/liter. The NDVV aerosol generated an average of 10(4)-10(5) 50% embryo infective dose per liter of air. In these experiments, E. faecalis and NDVV aerosols were successfully generated despite considerable initial particle loss. The bacteria and virus uptakes per chick are discussed in case day-old chicks would be exposed to these aerosols.
A murine osteosarcoma (OGS) cell line was permanently infected with Newcastle disease virus (NDV). The presence of NDV in the subsequent passages was demonstrated by haemadsorption and by immunofluorescence. Compared to the uninfected OGS line the persistently infected cells had a slightly reduced growth rate and they had a reduced sensitivity to several viruses, shown by several different methods. Interferon sensitivity was considerably reduced in the OGS-NDV cells, both the antiviral activity and the cell multiplication inhibitory activity.
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The nucleotide sequences of two monoclonal antibody-resistant mutant viruses predict changes from the wild-type in the number of potential glycosylation (Asn-X-Thr/Ser) in the mutant haemagglutinin-neuraminidase (HN) glycoproteins of the Beaudette C strain of Newcastle disease virus. The HN glycoproteins of these mutants, F5 and Z18, migrate either slower (F5) or faster (Z18) than that of the wild-type in SDS-PAGE. HN proteins synthesized in chick embryo fibroblasts following infection by either mutant or wild-type virus in the presence of tunicamycin (an inhibitor of glycosylation), comigrate on SDS-PAGE. These results confirm that the HN protein of the mutant virus, F5, has gained a glycosylation site at Asn(323)-Ser-Ser and that the conserved potential glycosylation site at Asn(481)-His-Thr is indeed glycosylated in the HN protein of the wild-type Beaudette C strain of Newcastle disease virus but is lost in that of the mutant virus, Z18.
A complete cDNA clone of the Newcastle disease virus (NDV) vaccine strain Hitchner B1 was constructed, and infectious recombinant virus expressing an influenza virus hemagglutinin was generated by reverse genetics. The rescued virus induces a strong humoral antibody response against influenza virus and provides complete protection against a lethal dose of influenza virus challenge in mice, demonstrating the potential of recombinant NDV as a vaccine vector.
In a part of the broiler flocks vaccinated against Newcastle disease (N.C.D) and infectious bronchitis (I.B.), disease symptoms of lingering nature have been observed, generally in the second half of the rearing period. In a practical investigation with weekly examinations of chickens, supplemented by a serological examination of twenty-four animals per flock at the age of six weeks, it was hoped to establish the factors responsible for this "vaccination reaction". In the district under notice the vaccination reaction syndrome had been responsible for widspread abandoning of twice spraying against N.C.D. in the first and fourth week in favour of drinking-water vaccination (generally combined with I.B. vaccination) in the second week and spray-vaccination in the fourth week or of combined drinking-water vaccination in the second week, either with or without N.C.D. drinking-water vaccination in the fourth week. Admittedly the incidence of vaccination reaction in flocks vaccinated exclusively via the drinking water was less frequent (32%) than in flocks in which the second vaccination was administered as a spray (48%), but this difference was largely accounted for by infection with Mycoplasma gallisepticum and/or Mycoplasma synoviae, complicated by infection with Escherichia coli. Of the thirty-three flocks free of mycoplasmosis, 24% exhibited the vaccination reaction, while the incidence to the fifteen infected flocks was 73.4%. In flocks infected with mycoplasmosis the course of E. coli infections was serious in 46.7% of the birds, while this figure was 18.2% in flocks free of mycoplasmosis. In flocks free of mycoplasmosis, the percentage of serious E. coli infections was lower after spray vaccination (14.3%) than after drinking-water vaccination (21%). The strains of E. coli brought in by one-day chicks from the hatchery disappear rapidly and play no role of any significance in the problem of colibacillosis observed at an age of three weeks or older. Of the 310 isolated strains of E. coli, 52 could not be typed and the others belonged to eighty different serotypes. With respect to the effect of infectious bronchitis the investigation does not provide sufficient evidence to permit of drawing conclusions. A significant role in the occurrence of the syndrome was played by coccidiosis and Gumboro's disease. With respect to environmental factors the available data did not allow of drawing conclusions. The authors recommend continuing with all available means to free the breeding animals from M. gallisepticum and M. synoviae, undertaking scientifically based research into the role of infectious bronchitis in the "vaccination reaction" syndrome, an effective programme of hygiene to control E...
Newly-hatched chickens were treated with 3 mg of cyclophosphamide (CY) per day for 4 consecutive days. At 2 weeks of age, these chickens, together with a group of untreated controls, were vaccinated intranasally or subcutaneously with the La Sota strain of Newcastle disease virus (NDV). All chickens were challenged intranasally with the GB strain of NDV 2 weeks later. CY-treated, intranasally vaccinated chickens were highly resistant to NDV challenge, yet none of the chickens produced any detectable humoral antibodies to NDV; antibodies to NDV were detectable in the tracheal washings, however.
The virions of Newcastle disease virus (NDV) contained an enzyme that catalyzed the incorporation of ribonucleotides into ribonucleic acid (RNA). Optimal conditions for this polymerase activity were identical to the conditions for the vesicular stomatitis virus (VSV) polymerase, and both enzymes were active for longer times at 32 C than at 37 C. However, the specific activity of the NDV polymerase was less than 3% that of the VSV polymerase. Product RNA species from the NDV and VSV polymerase reactions annealed specifically to the homologous virion RNA species. Transcriptive intermediates containing product RNA attached to the respective virion RNA could be identified in both systems.