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Results for “Infectious bronchitis virus”

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PubMed1976

Comparison of a microneutralization test in cell culture and virus neutralization test in embryonated eggs for determining infectious bronchitis virus antibodies.

A microneutralization test (MNT) system utilizing cytopathic effect end points was effective in determing neutralization indexes for infectious bronchitis virus antibodies. The system is reproducible within 1 index unit at the 95% level of probability. Comparison of the MNT to tests in eggs resulted in a positive correlation (B =0.81), which was significant (P greater than 0.01). The quantitative dose-response relationship of the MNT is linear (P greater than 0.005), with the 95% prediction limits fitting between one 10-fold dilution.

Analysis of Variance↗

PubMed2003

Expression of immunogenic S1 glycoprotein of infectious bronchitis virus in transgenic potatoes.

The expression of infectious bronchitis virus (IBV) S1 glycoprotein in potatoes and its immunogenicity in mice and chickens were investigated. Potato plants were genetically transformed with a cDNA construct encoding the IBV S1 glycoprotein with the Agrobacterium system. Genomic DNA and mRNA analyses of the transformed plantlets confirmed the integration of the foreign cDNA into the potato genome, as well as its transcription. Mice and chickens vaccinated with the expressed IBV S1 glycoprotein produced antibodies that neutralized IBV infectivity. After three immunizations, vaccinated chickens were completely protected from virulent IBV infection. These results demonstrate that transgenic potatoes expressing IBV S1 glycoprotein can be used as a source of recombinant antigen for vaccine production.

Base Sequence↗

PubMed2004

S1 and N gene analysis of avian infectious bronchitis viruses in Taiwan.

The disease caused by infectious bronchitis virus (IBV) produces great economic for the poultry industry. The purpose of this study is to investigate the molecular epidemiology of IBV in Taiwan. An old IBV strain isolated in 1964 and another 31 strains isolated from 1991 to 2003 were selected for N-terminal S1 gene analysis. Based on their phylogenetic tree, 13 strains were selected for sequencing the entire S1 and partial nucleocapsid (N) genes. The results indicated that Taiwanese IBV strains could be divided into two distinct lineages, Taiwan Group I and Taiwan Group II, with one Massachusetts strain and one Chinese strain. No recombination was found between H120 and the Taiwanese strains in the S1 gene. However, the S1 gene showed a noticeably higher divergence than the N gene. The phylogenetic trees constructed from the S1 and N genes indicate that intergenic recombination has occurred. Since most local strains are in Taiwanese clusters, developing vaccines from local strains is necessary for IBV control in Taiwan.

Amino Acid Sequence↗

PubMedDate not supplied

Pathogenicity of Australian strains of avian infectious bronchitis virus.

The pathogenicity of 25 strains of infectious bronchitis virus (IBV) isolated in Australia between 1961 and 1994 was compared in white leghorn specific pathogen-free chicks. Twelve strains were nephropathogenic and 10 respiratory, the other three being of mixed pathogenicity. The IBV strains identified as nephropathogenic induced clinical nephritis, gross and histological kidney lesions, and mortality of 5-90%. According to the severity of these features, the nephropathogenic strains could be further subdivided into strains of high, moderate or low pathogenicity. The three strains of mixed pathogenicity induced tracheitis, mild clinical nephritis and kidney lesions but no mortality. The 10 respiratory strains caused histological lesions in the trachea but not in the kidney, and did not induce clinical nephritis or mortality. Of 12 IBV strains isolated between 1961 and 1976, nine were nephropathogenic, inducing mortality of 15-90%. In contrast, of 13 strains isolated between 1981 and 1994, only three were nephropathogenic, inducing mortality of 5-37%, whereas nine were respiratory. Seven of these nine strains, unlike other respiratory strains, failed completely to replicate in the kidney. The results indicated a change in the prevalent IBV strains from highly nephropathogenic (1960s to 1970s) to respiratory (1980s to early 1990s); moreover, the late 1980s saw the emergence of respiratory strains with altered tissue tropism.

Animals↗

PubMed2003

S1 glycoprotein gene analysis of infectious bronchitis viruses isolated in Korea.

Fifteen isolates of Infectious bronchitis virus (IBV) were obtained from the kidney, trachea, and cecal tonsil of IB suspected chickens between 2001 and 2002 years in Korea. The S1 glycoprotein gene of IBV isolates were amplified by reverse transcriptase - polymerase chain reaction (RT-PCR) and analyzed by restriction fragment length polymorphism (RFLP) analysis. Fifteen Korean IBV isolates were classified into 4 groups by their RFLP patterns using restriction enzymes, HaeIII, BstYI, and XcmI. The RFLP patterns for 3, 1, and 1 of 15 isolates corresponded to the patterns of IBV Arkansas, Connecticut, and Massachusetts strains, respectively. Ten of 15 isolates generated unique KM91 RFLP pattern that was observed in the IBV KM 91 strain previously isolated in Korea. To confirm genetic diversity in the S1 genes of IBV isolates, viral RNAs of representative 9 of 15 IBV isolates were amplified, cloned, sequenced and compared with published sequences for non-Korean IBV strains. Korean IBV isolates showed amino acid sequence similarity between 61.8% (K446-01 and K161-02) and 96.1% (K281-01 and K210-02) with each other and they showed amino acid sequence similarity between 42.9% (K161-02 and GA980470) and 96.5% (K203-02 and KB8523) compared to non-Korean IBV strains. By phylogenetic tree analysis, Korean IBV field isolates were branched into five clusters in which 3 clusters were differentiated from non-Korean IBV strains. Especially, Korean IBV isolates K069-01, K507-01, K774-01 and K142-02 formed a separate cluster. It seems that IBVs continue to evolve and IBVs showing various genetic differences may cocirculate in Korea.

Amino Acid Sequence↗

PubMedDate not supplied

Construction and immunogenicity studies of recombinant fowl poxvirus containing the S1 gene of Massachusetts 41 strain of infectious bronchitis virus.

The spike 1 (S1) surface glycoprotein of infectious bronchitis virus (IBV) is the major inducer of the generation of virus neutralizing antibodies, and the administration of purified S1 has been shown to elicit a protective immune response against virulent virus challenge. On the basis of these observations, recombinant fowl poxvirus (rFPV) containing a cDNA copy of the S1 gene of IBV Mass 41 (rFPV-S1) was constructed and its immunogenicity and vaccine potential were evaluated. Initially, rFPV-S1 was shown to express the S1 in vito by indirect immunofluorescence staining and western blot analyses. Later, in vivo expression was demonstrated by the detection of IBV-specific serum immunoglobulin G and neutralization antibodies in the sera of chickens immunized with rFPV-S1. That the recombinant virus elicited anti-IBV protective immunity was indicated by the manifested, relatively mild clinical signs of disease, decreased titers of recovered challenge virus, and less severe histologic changes of the tracheas in virulent IBV Mass 41-challenged chickens previously receiving rFPV-S1 as compared with parental fowl poxvirus (FPV)-vaccinated control birds. In contrast, chickens immunized with either recombinant or parental FPV were resistant to a subsequent virulent FPV challenge. As to a preferred method of immunization, wing web administration appeared to be superior to the subcutaneous route because a greater percentage of birds vaccinated by the former protocol exhibited an anti-IBV humoral immune response. Thus, rFPV-S1 has potential as a poultry vaccine against both fowl pox and infectious bronchitis.

Allantois↗

PubMedDate not supplied

Identification of field isolates of infectious bronchitis virus by interference with the La Sota of strain of Newcastle disease virus.

The interference phenomenon of infectious bronchitis virus (IBV) with growth of Newcastle disease virus (NDV) in embryonating chicken eggs (ECE) was used as a diagnostic method. Fifteen field isolates obtained from presumptively infectious-bronchitis-affected chickens were analyzed by the IBV-NDV interference test. Eight isolates were capable of interfering with the growth of the La Sota strain of NDV, as measured by hemagglutination (HA) activity when IBV was inoculated 10 hr before NDV into ECE. The interference was considered specific for IBV, because it could be eliminated by adding homologous anti-IBV serum. The sensibility of this method could be demonstrated, because in some cases low-passage levels of IBV isolates showing HA interference ability were not capable of producing lesions in ECE. Furthermore, serologically negative IBV samples did not interfere with NDV growth. From these results, the IBV-NDV interference test appears to be a potential diagnostic alternative for identifying IBV field isolates.

Animals↗

PubMed2000

Utilizing fowlpox virus recombinants to generate defective RNAs of the coronavirus infectious bronchitis virus.

Coronavirus defective RNAs (D-RNAs) have been used as RNA vectors for the expression of heterologous genes and as vehicles for reverse genetics by modifying coronavirus genomes by targetted recombination. D-RNAs based on the avian coronavirus infectious bronchitis virus (IBV) D-RNA CD-61 have been rescued (replicated and packaged into virions) in a helper virus-dependent manner following electroporation of in vitro-generated T7 transcripts into IBV-infected cells. In order to increase the efficiency of rescue of IBV D-RNAs, cDNAs based on CD-61, under the control of a T7 promoter, were integrated into the fowlpox virus (FPV) genome. The 3'-UTR of the D-RNAs was flanked by a hepatitis delta antigenomic ribozyme and T7 terminator sequence to generate suitable 3' ends for rescue by helper IBV. Cells were co-infected simultaneously with IBV, the recombinant FPV (rFPV) containing the D-RNA sequence and a second rFPV expressing T7 RNA polymerase for the initial expression of the D-RNA transcript, subsequently rescued by helper IBV. Rescue of rFPV-derived CD-61 occurred earlier and with higher efficiency than demonstrated previously for electroporation of in vitro T7-generated RNA transcripts in avian cells. Rescue of CD-61 was also demonstrated for the first time in mammalian cells. The rescue of rFPV-derived CD-61 by M41 helper IBV resulted in leader switching, in which the Beaudette-type leader sequence on CD-61 was replaced with the M41 leader sequence, confirming that helper IBV virus replicated the rFPV-derived D-RNA. An rFPV-derived D-RNA containing the luciferase gene under the control of an IBV transcription-associated sequence was also rescued and expressed luciferase on serial passage.

Animals↗

PubMed1984

A leader sequence is present on mRNA A of avian infectious bronchitis virus.

The subgenomic mRNAs of the fowl coronavirus infectious bronchitis virus (IBV) form a 3' co-terminal or 'nested' set. The RNase T1 oligonucleotide mapping data which demonstrated this form of sequence organization provided no evidence for the presence of non-contiguous (leader) sequences fused to the 5' termini of the mRNAs. However, we have been able to demonstrate, by extension of an end-labelled synthetic oligonucleotide primer, the presence of a leader sequence on IBV mRNA A. Sequencing by the chemical degradation method of the extended product has yielded the almost complete sequence of the 60 base leader and its point of fusion to the sequence of the virus genomic RNA.

Base Sequence↗

PubMed1980

Coronavirus multiplication strategy. II. Mapping the avian infectious bronchitis virus intracellular RNA species to the genome.

Avian infectious bronchitis virus, a coronavirus, directed the synthesis of six major single-stranded polyadenylated RNA species in infected chicken embryo kidney cells. These RNAs include the intracellular form of the genome (RNA F) and five smaller RNA species (RNAs A, B, C, D, and E). Species A, B, C, and D are subgenomic RNAs and together with the genome form a nested sequence set, with the sequences of each RNA contained within every larger RNA species (D. F. Stern and S. I. T. Kennedy, J. Virol 34:665-674, 1980). In the present paper we show by RNase T1 oligonucleotide fingerprinting that RNA E is also a member of the nested set. Partial alkaline fragmentation of the genome followed by sucrose fractionation, oligodeoxythymidylate-cellulose chromatography, and RNase T1 fingerprinting gave a partial 3'-to-5' oligonucleotide spot order. A comparison of the oligonucleotides of each of the five subgenomic RNAs with this spot order established that all of the RNAs are comprised of nucleotide sequences inward from the 3' end of the genome. This result is discussed in relation to the multiplication strategy both of coronaviruses and of other RNA-containing viruses.

Base Sequence↗

PubMedDate not supplied

Isolation of infectious bronchitis virus from broiler chickens in Chile.

An infectious-bronchitis-like virus was isolated from 6-week-old broiler chickens unvaccinated with infectious bronchitis virus (IBV). The isolate produced lesions in embryonating chicken eggs (ECE) and clinical signs in birds characteristic of IBV. Serum-neutralization and agar-gel diffusion tests demonstrated the serological relationship of this isolate to IBV.

Animals↗

PubMed1986

In ovo interference of embryo non-lethal avian infectious bronchitis viruses (IBV) with velogenic Newcastle disease virus and embryo adapted IBV.

Avian infectious bronchitis virus (IBV) interfered with the lethal effects of velogenic Newcastle disease virus (NDV) and embryo adapted IBV in eggs previously inoculated with non-lethal IBV. Greater interference was noted in eggs superinfected with embryo adapted IBV than velogenic NDV. The interference could be eliminated by treating the initial IBV with homologous anti-IBV serum.

Animals↗

PubMed1997

Identification of amino acids involved in a serotype and neutralization specific epitope within the s1 subunit of avian infectious bronchitis virus.

Localization of neutralizing, serotype specific epitopes of infectious bronchitis virus has been difficult because these epitopes are conformationally dependent. We identified amino acids involved in a serotype specific, conformationally dependent epitope by analysis of the S1 gene of 13 monoclonal antibody-neutralization-resistant mutants. Substitutions in the predicted amino acid sequence of these mutants were located at residues 304 and/or 386. Most of the substitutions at residue 304 were from threonine to isoleucine, whereas the substitutions at residue 386 were from arginine to proline, histidine, cysteine, or tryptophan. Based on this data, it appears that AA residues at 304 and 386 on the S1 glycoprotein are involved in a virus neutralizing serotype specific epitope.

Amino Acids↗

PubMed1978

Induction of chicken interferon by avian infectious bronchitis virus.

The ability of nine strains of avian infectious bronchitis virus (IBV) to induce chicken interferon has been investigated using Semliki Forest virus for the tests. The Beaudette, H120 and Connecticut 46 strains induced interferon in the allantoic fluids of embryonated hens' eggs, the highest titre (1 : 30) being associated with Beaudette; but these as well as the Massachusetts M-41 and H52 strains failed to yield interferon in primary monolayer cultures of chick kidney cells as did all nine strains in organ cultures of chick embryo trachea. None of six strains of IBV investigated was susceptible to the inhibitory effects of chicken interferon.

Animals↗

PubMed2004

Egg:embryo weight ratio as an indicator of dwarfism induced by infectious bronchitis virus.

A simple objective method to quantify embryo dwarfism induced by infectious bronchitis virus in embryonated chicken eggs has been used to determine endpoints in virus titration and neutralization assays. The eggs and the respective embryos were weighed and embryo:egg weight (EE) ratios were calculated. The EE ratios were compared with the uninoculated control eggs and endpoints could be calculated objectively. EE indices were also calculated by dividing the EE ratios of inoculated embryonated chicken eggs by the mean EE ratio of uninoculated controls, or in the case of virus neutralization tests by the mean EE ratio of eggs inoculated with virus alone. Although this mean EE index did not reflect the dwarfing (or lack of it) in individual eggs, it served as a group indicator. This method would be useful to observe embryo lesions especially in field (non-egg adapted) infectious bronchitis virus isolates, which does not cause observable dwarfing until several embryo passages.

Animals↗

PubMed2005

Molecular characterization of avian infectious bronchitis virus strains isolated in Colombia during 2003.

Sixteen infectious bronchitis virus (IBV) isolates were recovered from broilers and layers from five geographic poultry regions in Colombia. The viruses were isolated from tracheas, lungs, and cecal tonsils of birds, previously vaccinated with the Massachusetts strain, that were showing respiratory signs. Further analysis of the IBV isolates was achieved by phylogenetic analysis comparing their deduced amino acid sequences in the hypervariable region 1 of the S1 gene with reference strains. Four unique genotype clusters containing isolates with indigenous genotypes were observed. One isolate was found to be the Connecticut genotype and three isolates were found to be the Massachusetts genotype.

Animals↗

PubMed2005

Differential localization and turnover of infectious bronchitis virus 3b protein in mammalian versus avian cells.

Infectious bronchitis virus (IBV) 3b protein is highly conserved among group 3 coronaviruses, suggesting that it is important for infection. A previous report (Virology 2003, 311:16-27) indicated that transfected IBV 3b localized to the nucleus in mammalian cells using a vaccinia-virus expression system. Although we confirmed these findings, we observed cytoplasmic localization of IBV 3b with apparent exclusion from the nucleus in avian cells (IBV normally infects chickens). IBV 3b was virtually undetectable by microscopy in mammalian cells transfected without vaccinia virus and in IBV-infected mammalian cells because of a greatly reduced half-life in these cells. A proteasome inhibitor stabilized IBV 3b in mammalian cells, but had little effect on IBV 3b in avian cells, suggesting that rapid turnover of IBV 3b in mammalian cells is proteasome-dependent while turnover in avian cells may be proteasome-independent. Our results highlight the importance of using cells derived from the natural host when studying coronavirus non-structural proteins.

Animals↗

PubMed1997

Specific cytotoxic T lymphocytes are involved in in vivo clearance of infectious bronchitis virus.

Cytotoxic T-lymphocyte (CTL) responses to infectious bronchitis virus (IBV) were determined at regular intervals between 3 and 30 days postinfection (p.i.). The maximum response with 82% lysis of labeled target cells was detected at 10 days p.i. The specific CTL response did not begin to decline until the amount of virus, which peaked at day 8 p.i. in both the kidneys and lungs, started to decrease. Clinical respiratory signs of illness also correlated with amount of virus. CTL activity was shown to be major histocompatibility complex (MHC) class restricted because the lysis of MHC-mismatched targets was negligible, and lysis was mediated by CD8+ CD4- T cells, as the CTL response could be abolished with removal of CD8+ CD4- but not CD4+ CD8- lymphocytes. In contrast, immunoglobulin M (IgM) antibody was not detected until day 10 p.i., and levels peaked at day 12 p.i.; IgG antibody levels were minimal until day 15 p.i. but continued to increase exponentially until day 30 p.i., the last day examined. In summary, CTL responses correlated with initial decreases in infection and illness.

Animals↗