PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Infectious bronchitis virus”

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 145 records · Page 8Linked to original sources
PubMedDate not supplied

Serum antibody responses of chickens following sequential inoculations with different infectious bronchitis virus serotypes.

Sequential inoculations of chickens with different live infectious bronchitis virus (IBV) antigenic types had major effects on virus-neutralization (VN) and hemagglutination-inhibition (HI) serum antibody responses. Antibody production in IBV-inoculated chickens that were reinoculated 8 weeks later with heterologous virus was largely directed against the virus used for initial inoculation rather than the virus used for reinoculation. In addition, chickens inoculated sequentially with IBV produced a broadened spectrum of serum antibodies that reacted with IBV types to which the birds had never been exposed (JMK and Florida). Chickens inoculated sequentially with heterologous IBV tended to produce higher levels of cross-reacting antibody than birds given homologous virus inoculations. Levels of cross-reacting antibodies were lower than levels of specific antibodies directed against viruses that the birds had received. Limited studies indicated that birds with cross-reacting antibodies were not protected against challenge with the virus that the cross-reacting antibody was directed against. Implications of the research for interpreting serological data from commercial chicken flocks are discussed.

Animals↗
PubMedDate not supplied

Preparing hemagglutinating antigen from isolates of infectious bronchitis virus.

The hemagglutinating (HA) activity of 14 strains of infectious bronchitis virus (IBV) was investigated. The optimal conditions for IBV antigen preparation include inoculation of 10- or 11-day-old specific pathogen-free embryonated eggs and incubation for 30 hours at 37 C. Embryos were inoculated via the allantoic cavity with 0.1 ml of a low embryonic passage of the virus (10(7) to 10(8) EID50/ml). Allantoic fluid was harvested and pooled, and a 100-fold concentration of virus particles was achieved by centrifugation for 3 hours at 30,000 x g. Virus pellets were resuspended in Tris-hydrochloride buffer containing 3 units of phospholipase-C (type-1) enzyme/ml and incubated for 2 hours at 37 C. All IBV strains tested demonstrated positive HA activity with chicken red blood cells. The antigen was stored in liquid state or lyophilized at 4 C.

Animals↗
PubMed2001

Origin and evolution of Georgia 98 (GA98), a new serotype of avian infectious bronchitis virus.

We previously identified GA98, a new serotype of infectious bronchitis virus (IBV), which is closely related to the DE072 serotype of IBV genetically, but not antigenically. Herein, we analyzed the 421bp sequence of a hypervariable region (HVR) (position 114-534, counting from the ATG start site) of the S1 subunit of GA98 IBVs to further examine the evolution of these viruses. These viruses were isolated between the years 1997 and 2000. Phylogenetic analysis of the deduced amino acid sequence on that region indicated that GA98 isolates from different regions of Georgia were the result of a single introduction of the S1 gene of the DE072 serotype progenitor. Most of the mutations were nonsynonymous and had become fixed in a progressive manner. The evolutionary and mutation rates in the HVR was calculated as 2.5 and 1.5% per year, respectively. This new serotype of IBV appears to be evolving very fast compared with other serotypes of IBV. We further determined the complete coding sequence of the S1 gene of seven isolates obtained from one selected region in North Georgia. Together with virus neutralization data, it appears that GA98 arose from immune selection caused by DE072 vaccine use. Reasons for this conclusion are discussed.

Amino Acid Sequence↗
PubMed1975

Effect of pH on the growth and cytopathogenicity of avian infectious bronchitis virus in chick kidney cells.

The growth of avian infectious bronchitis virus (IBV) in chick kidney cells at different pH values in the range 6.0-9.0 demonstrated that although the virus was released at a much faster rate at the higher pH values the titre tended to drop more quickly. At the acid pH values the virus was released more slowly but reached a maximum titre similar to that at the higher pH values and showed only minimum reduction in infectivity up to 49 hours post inoculation. The stability of virus in tissue culture medium was shown to be directly related to pH 6.0-8.0, being more stable at the acid pH values. The degree of cytopathogenicity induced in chick kidney cells following infection with IBV was directly related to the pH at which the cells were incubated, occurring earlier and more extensively in cells at the higher pH values. Cell macromolecule synthesis in chick kidney cells was inhibited following infection with IBV and was apparently due to cell damage and death.

Animals↗
PubMed2006

Antigenic and molecular characterization of isolates of the Italy 02 infectious bronchitis virus genotype.

As part of an epidemiological surveillance of infectious bronchitis virus (IBV) in Spain, four Spanish field isolates showed high S1 spike sequence similarities with an IBV sequence from the GenBank database named Italy 02. Given that little was known about this new emergent IBV strain we have characterized the four isolates by sequencing the entire S1 part of the spike protein gene and have compared them with many reference IBV serotypes. In addition, cross-virus neutralization assays were conducted with the main IBV serotypes present in Europe. The four Spanish field strains and the Italy 02 S1 sequence from the NCBI database were established as a new genotype that showed maximum amino acid identities with the 4/91 serotype (81.7% to 83.7%), the D274 group that included D207, D274 and D3896 strains (79.8% to 81.7%), and the B1648 serotype (79.3% to 80%). Furthermore, on the basis of these results, it was demonstrated that the Italy 02 genotype had been circulating in Spain since as early as 1997. Based on the average ratio of synonymous:non-synonymous (dS/dN) amino acid substitutions within Italy 02 sequences, no positive selection pressures were related with changes observed in the S1 gene. Moreover, phylogenetic analysis of the S1 gene suggested that the Italy 02 genotype has undergone a recombination event. Virus neutralization assays demonstrated that little antigenic relatedness (less than 35%) exists between Italy 02 and some of the reference IBV serotypes, and indicated that Italy 02 is likely to be a new serotype.

Amino Acid Sequence↗
PubMed1979

Effect of incubation temperature on infectivity titration of mouse brain-passaged avian infectious bronchitis virus in laboratory host systems.

Mouse brain-passaged infectious bronchitis virus (IBV) could not be assayed for its infectivity at 39.5 degrees C, but could be so at 37 degrees C and 39.5 degrees C. Antigen accumulation was not detected by immunofluorescence in CEK cells infected with mouse brain-passaged IBV at 39.5 degrees C, perhaps due to the difference in the cellular environments.

Animals↗
PubMed2002

An ELISA for antibodies against infectious bronchitis virus using an S1 spike polypeptide.

Using the whole infectious bronchitis virus (IBV) for detecting the antibody against IBV by enzyme-linked immunosorbent assay (ELISA) is a routine work in poultry industry. To prepare virus is time consuming and tedious. Furthermore, the whole viral antigen detects all antibodies against the viral structural proteins, including spike (S), nucleocapsid, matrix, and other proteins. Among those, S protein is related to neutralization. Thus, to develop and express protein fragment from S gene and to use the protein as a coating antigen for antibody detection against IBV are the purposes of this experiment. A partial S gene fragment (n.t. 1143-1665) was cloned into pRSET vectors and transformed into competent Escherichia coli (E. coli) BL21 (DE3). A 27.5 kDa fusion protein (S-fg, containing S1-F and partial S2-G antigenic sites) was successfully expressed, affinity-purified and detected specifically with chicken anti-IBV serum by Western blot. The expressed S-fg protein was used as a coating antigen for developing an ELISA (S-fg ELISA) for serum antibody detection in anti-IBV antisera from different IBV serotypes and in field sera. The results show that the S-fg fusion protein is highly cross-reactive among different IBV serotypes, and the S-fg ELISA is found to be a convenient, economical, and efficient method for antibody detection against IBV.

Animals↗
PubMed1982

Coronavirus proteins: structure and function of the oligosaccharides of the avian infectious bronchitis virus glycoproteins.

The recent finding that the E1 glycoproteins of murine coronaviruses contain only O-linked oligosaccharides suggested that this unusual modification might be a distinguishing feature of coronaviruses and might play an essential role in the life cycle of this family of viruses. To examine these possibilities, we analyzed the oligosaccharide moieties of the membrane proteins of the avian coronavirus infectious bronchitis virus. In addition, we determined the effect of inhibiting the glycosylation of these proteins on viral maturation and infectivity. Infectious bronchitis virus virions contain nine proteins. Four of these proteins, GP36, GP31, GP28, and P23, are closely related structurally and appear to be homologous to the E1 proteins of murine coronaviruses. We found that the oligosaccharides of GP31 and GP28 could be removed with endoglycosidase H and that neither of these glycoproteins was detectable in tunicamycin-treated cells. These two results indicated that GP31 and GP28 contain N-linked oligosaccharides. Therefore, O-linked oligosaccharides are not a universal feature of the small coronavirus membrane glycoproteins. Tunicamycin inhibited glycosylation of all of the viral glycoproteins but did not inhibit production of virions by infectious bronchitis virus-infected cells. The virions released by these cells contained only the three non-glycosylated viral proteins P51, P23, and P14. These particles were not infectious. Therefore, it appears that glycosylated infectious bronchitis virus polypeptides are not required for particle formation. However, the viral glycoproteins are apparently indispensible for viral infectivity.

Animals↗
PubMed1993

Oligonucleotide probes in infectious bronchitis virus diagnosis and strain identification.

Genomic RNA fingerprints of infectious bronchitis virus (IBV) strains M41 and Conn46 were prepared to identify T1 RNase-resistant oligonucleotides 'unique' to each of the two IBV strains. Such oligonucleotides were subsequently eluted from the gels and their nucleotide sequences determined. When oligonucleotide probes of those sequences were synthesized and used in a dot-blot hybridization assay, the probes lacked IBV strain-specificity and reacted with the RNAs of homologous as well as heterologous IBV strains. Based on these results, the methods used in this study need to be applied to a large number of oligonucleotide probes, to find one or a few that might be suitable as IBV strain- or serotype-specific oligonucleotide probes.

Animals↗
PubMed1980

The polypeptides of infectious bronchitis virus (IBV-41 strain).

The Massachusetts strain of avian infectious bronchitis virus was purified from embryonated hens' eggs. Four major species of apparent mol. wt. 90 000, 52 000, 29 000 and 26 000 were resolved by SDS-polyacrylamide gel electrophoresis. Omission of reducing agent failed to resolve the 29 000 mol. wt. component. Labelling of acrylamide gels with 125I-concanavalin A indicated that polypeptides of mol. wt. 90 000, 29 000 and 26 000 were glycosylated and, in the absence of reducing agent, that the 29 000 species migrated as a dimer in the 5000 mol. wt. region. Purified IBV radio-iodinated with Bolton and Hunter reagent, which banded as a single peak of radioactivity in Metrizamide gradients, was found to contain bands of radioactivity when analysed by SDS-PAGE, corresponding to the polypeptides of mol. wt. 90 000, 52 000 and 29 000 resolved in stained gels. Disruption of IBV particles in Triton X-100 released two subviral particles, a 16 nm spike which comprised polypeptides of 90 000, 52 000 and 29 000 mol. wt. and another denser spherical particle of 25 to 45 nm which contained RNA and the 52 000 and 26 000 polypeptides.

Bromelains↗
PubMed1998

Recombinant nucleocapsid protein is potentially an inexpensive, effective serodiagnostic reagent for infectious bronchitis virus.

The nucleocapsid protein of the Gray strain of infectious bronchitis virus (IBV) is highly immunogenic and cross-reactive among various distinct serotypes. Recombinant nucleocapsid polypeptide expressed in bacteria with a histidine tag at the amino terminus has been used as antigen for developing an assay to detect IBV-specific antibody. This fusion protein was produced readily in bacteria and easily purified with a nickel column which bound to the histidine tag. Conditions were optimized for using these preparations for an IBV-specific ELISA. Although differences in optical densities could be detected between pre-immune and positive sera for the Ark, Mass, and Gray strains with antigen concentrations between 50 and 0.1 microg per well, the greatest differences could be detected with 3 and 1.5 microg of protein per well. Maximum differences in optical densities between pre-immune and positive sera were obtained using 2.4 microg per well of protein and sera diluted between 1:80 and 1:160. In addition, as little as 30 ng/dot of recombinant nucleocapsid consistently detected IBV-specific sera in immunoblot assays which have convenient field applications.

Animals↗
PubMedDate not supplied

Infectious bronchitis virus antibodies in tears and their relationship to immunity.

Antibodies to infectious bronchitis virus (IBV) in chicken tears were investigated to determine if they could be used as an indicator of protective immunity. Antibody production in tears and serum was measured by enzyme-linked immunosorbent assay (ELISA) in specific-pathogen-free (SPF) white leghorn and broiler chickens vaccinated with a live attenuated vaccine containing the Massachusetts (Mass) Connaught strain of IBV. The effect of virulent infectious bursal disease virus (IBDV) infection on antibody production in tears was also evaluated. Immunity was assessed by challenging the chickens with Mass 41 and performing tracheal swabbings 5 days later. In addition, tears were also evaluated for virus-neutralizing (VN) antibodies to IBV. Following eyedrop vaccination, anti-IBV antibodies were consistently detected by ELISA in tears prior to and in higher concentrations than in the sera of SPF white leghorn and broiler chickens. Maternal IBV antibodies were present in the tear secretions of broiler chickens but in lower concentrations than in sera. Infection of SPF chicks with a virulent and immunosuppressive strain of IBDV at 1 day of age greatly reduced IBV ELISA antibody production in tears as well as serum compared with infection of chickens with IBDV at 14 days of age. IBV ELISA and VN antibody levels in tears were not accurate indicators of IBV immunity as determined by challenge with Mass 41. High tear IBV antibody titers were observed in some chickens determined to be susceptible to IBV challenge and low tear titers were detected in some protected chickens. This finding suggests that mechanisms other than antibody-mediated immunity in tears are important in viral clearance following challenge.

Animals↗
PubMed1994

Evolutionary implications of genetic variations in the S1 gene of infectious bronchitis virus.

The large number of phenotypically distinct strains of infectious bronchitis virus (IBV) provide a broad genetic background for examining naturally occurring coronavirus variation. Comparisons of the published nucleotide sequence of S1 genes of strains isolated in Europe, Japan and the USA and four additional American strains described in this report identified 4 genetically distinct groups. The Dutch group was the most divergent sharing only about 60% identity with the American, Mass and European groups which were about 80% homologous with each other. Whereas the strains within the Mass, European and Dutch strains were at least 95% homologous, the strains within the American group were most variable, sharing about 80% identity. The hypervariable region (HVR) which tended to correlate with serotype extended from amino acid residue 53 to 148. In addition to the previously described putative recombination events in the S1 gene of PP14 and SE17, we have now described similar shifts in homology in the corresponding gene of the Gray, Holte, 6/82 (European strain), and Iowa strains. Although minor cross-over sites were identified in the more conserved 3' end at approximately nt 1000 and 1400, a frequently used hot-spot for recombination extended from nt 25 to a region immediately upstream of, but not including, the hypervariable region (HVR). In addition to point mutations, deletions, and insertions, recombination often involving Mass-like and Ark-like sequences, is a commonly used mechanism responsible for the evolution of IBV.

Amino Acid Sequence↗
PubMed2005

Contribution of trafficking signals in the cytoplasmic tail of the infectious bronchitis virus spike protein to virus infection.

Coronavirus spike (S) proteins are responsible for binding and fusion with target cells and thus play an essential role in virus infection. Recently, we identified a dilysine endoplasmic reticulum (ER) retrieval signal and a tyrosine-based endocytosis signal in the cytoplasmic tail of the S protein of infectious bronchitis virus (IBV). Here, an infectious cDNA clone of IBV was used to address the importance of the S protein trafficking signals to virus infection. We constructed infectious cDNA clones lacking the ER retrieval signal, the endocytosis signal, or both. The virus lacking the ER retrieval signal was viable. However, this virus had a growth defect at late times postinfection and produced larger plaques than IBV. Further analysis confirmed that the mutant S protein trafficked though the secretory pathway faster than wild-type S protein. A more dramatic phenotype was obtained when the endocytosis signal was mutated. Recombinant viruses lacking the endocytosis signal (in combination with a mutated dilysine signal or alone) could not be recovered, even though transient syncytia were formed in transfected cells. Our results suggest that the endocytosis signal of IBV S is essential for productive virus infection.

Animals↗
PubMed1995

Generation of a defective RNA of avian coronavirus infectious bronchitis virus (IBV). Defective RNA of coronavirus IBV.

The Beaudette strain of IBV was passaged 16 times in chick kidney (CK) cells. Total cellular RNA was analyzed by Northern hybridization and was probed with 32P-labeled cDNA probes corresponding to the first 2 kb of the 5' end of the genome, but excluding the leader, and to the last 1.8 kb of the 3' end of the genome. A new, defective IBV RNA species (CD-91) was detected at passage six. The defective RNA, present in total cell extract RNA and in oligo-(dT)30-selected RNA from passage 15, was amplified by the reverse transcription-polymerase chain reaction (RT-PCR) to give four fragments. The oligonucleotides used were selected such that CD-91 RNA, but not the genomic RNA, would be amplified. Cloning and sequencing of the PCR products showed that CD-91 comprises 9.1 kb and has three regions of the genome. It contains 1133 nucleotides from the 5' end of the genome, 6322 from gene 1b corresponding to position 12423 to 18744 in the IBV genome and 1626 from the 3' end of the genome. At position 749 one nucleotide, an adenine residue, was absent from CD-91 RNA. By Northern hybridization CD-91 RNA was detected in virions in higher amounts than the subgenomic mRNAs.

Animals↗
PubMed1992

Identification of two new polypeptides encoded by mRNA5 of the coronavirus infectious bronchitis virus.

The second smallest subgenomic messenger RNA, mRNA5, of the coronavirus infectious bronchitis virus includes in its "5' unique region" two separate open reading frames (5a and 5b), whose coding function has not so far been established, and thus it may represent a dicistronic messenger RNA. We report here that two polypeptides with the sizes expected for the 5a and 5b products can be synthesised by in vitro translation of a single artificial mRNA containing both the 5a and 5b ORFs. To establish whether these polypeptides represent genuine virus gene products, both the 5a and 5b coding sequences were expressed as bacterial fusion proteins, and these were used to raise monospecific antisera. Antisera raised against both the 5a and 5b-specific sequences recognized specifically proteins of the expected size in infectious bronchitis virus-infected chicken kidney and Vero cells, indicating that 5a and 5b do represent genuine virus genes, and suggesting that mRNA5 is indeed functionally dicistronic.

Base Sequence↗
PubMed1991

Protein pI alteration related to strain variation of infectious bronchitis virus, an avian Coronavirus.

Viral proteins of two strains of infectious bronchitis virus (IBV), which have different tissue trophism and serology, were separated on the basis of their isoelectric points (pI). The viruses have four structural proteins; the protein of greatest serological importance is found at the peplomer tip. The viral structural proteins separated by isoelectric focusing were identified by comparison to SDS-PAGE separations. Three protein bands were identical in pI and one protein band showed a difference in pI between strains. When the renatured viral proteins were Western blotted and reacted with strain-specific antiserum, antigen-antibody complexing was seen only at points corresponding to the strain-specific variant bands. For IBV strain Mass-41, antigen-antibody complexing occurred at a pI of 6.8, and, for IBV strain Ark-99, at 7.2. No cross reaction of antisera was observed for either strain. Since tissue affinities are a function of the viral peplomer-mediated attachment of virus to cells and are often directly related to pathogenicity, it appears that altered pathogenicity of strains of IBV may be detected by alteration of pI of the proteins. Classification by pI of proteins of at least the smaller viruses allows untypeable, highly pathogenic or persistent strains of these viruses to be characterized on the basis of variant proteins.

Antibodies, Viral↗