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genome of infectious bronchitis virus.techniques are described for the growth and rapid purification of the avian coronavirus infectious bronchitis virus (ibv). purified ibv has a sedimentation coefficient of 320s and a buoyant density of 1.22 g/ml in sucrose-deuterium oxide equilibrium gradients. ibv rna extracted by proteinase k in the presence of sodium dodecyl sulfate and further purified by phenol extraction and gradient centrifugation is single stranded and has a sedimentation coefficient of 64s, as determined by isokinetic gr ...1977198590
biological properties of avian coronavirus rna.rna with a sedimentation coefficient of 64s was isolated from infectious bronchitis virus, an avian coronavirus. the sna contained a polyadenylic acid tract and was found to be infectious.1977199697
induction of anti-viral immune responses by immunization with recombinant-dna encoded avian coronavirus nucleocapsid protein.immune responses to the infectious bronchitis virus (ibv) nucleocapsid protein were studied using a recombinant-dna expression product. in mice, a lymphocyte proliferative response and a delayed-type hypersensitivity reaction to ibv were induced upon immunization with this nucleocapsid protein. next, we studied the role of the expressed nucleocapsid protein in induction of a protective immune response to ibv in chickens. chickens were primed with nucleocapsid protein and subsequently boosted wit ...19921311490
a golgi retention signal in a membrane-spanning domain of coronavirus e1 protein.the e1 glycoprotein from an avian coronavirus is a model protein for studying retention in the golgi complex. in animal cells expressing the protein from cdna, the e1 protein is targeted to cis golgi cisternae (machamer, c. e., s. a. mentone, j. k. rose, and m. g. farquhar. 1990. proc. natl. acad. sci. usa. 87:6944-6948). we show that the first of the three membrane-spanning domains of the e1 protein can retain two different plasma membrane proteins in the golgi region of transfected cells. both ...19911655802
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 differenc ...19911658026
sequence evidence for rna recombination in field isolates of avian coronavirus infectious bronchitis virus.under laboratory conditions coronaviruses were shown to have a high frequency of recombination. in the netherlands, vaccination against infectious bronchitis virus (ibv) is performed with vaccines that contain several life-attenuated virus strains. these highly effective vaccines may create ideal conditions for recombination, and could therefore be dangerous in the long term. this paper addresses the question of the frequency of recombination of avian coronavirus ibv in the field. a method was s ...19901708184
localization of a t-cell epitope within the nucleocapsid protein of avian coronavirus.in a previous study, two murine t-cell hybridomas generated after immunization with infectious bronchitis virus (ibv) were shown to be responsive to the internally localized viral nucleocapsid protein. in the present study, the antigenic determinants were mapped using recombinant expression products and synthetic peptides. both hybridomas recognized the region spanning amino acid residues 71 to 78 of the nucleocapsid protein. the experimentally determined epitope corresponded with predicted moti ...19911718856
the complete sequence (22 kilobases) of murine coronavirus gene 1 encoding the putative proteases and rna polymerase.the 5'-most gene, gene 1, of the genome of murine coronavirus, mouse hepatitis virus (mhv), is presumed to encode the viral rna-dependent rna polymerase. we have determined the complete sequence of this gene of the jhm strain by cdna cloning and sequencing. the total length of this gene is 21,798 nucleotides long, which includes two overlapping, large open reading frames. the first open reading frame, orf 1a, is 4488 amino acids long. the second open reading frame, orf 1b, overlaps orf 1a for 75 ...19911846489
mhc class ii-restricted t-cell hybridomas recognizing the nucleocapsid protein of avian coronavirus ibv.mice were immunized with purified infectious bronchitis virus (ibv), strain m41. spleen cells, expanded in vitro by stimulation with m41, were immortalized by fusion to obtain t-cell hybridomas, and two major histocompatability complex (mhc) class ii (i-e)-restricted t-cell hybridomas were selected with specificity for ibv. both hybridomas selectively recognized the internal nucleocapsid protein. the responses to 12 different strains of ibv varied markedly. this demonstrates antigenic variation ...19911847691
the primary structure and expression of the second open reading frame of the polymerase gene of the coronavirus mhv-a59; a highly conserved polymerase is expressed by an efficient ribosomal frameshifting mechanism.sequence analysis of a substantial part of the polymerase gene of the murine coronavirus mhv-a59 revealed the 3' end of an open reading frame (orf1a) overlapping with a large orf (orf1b; 2733 amino acids) which covers the 3' half of the polymerase gene. the expression of orf1b occurs by a ribosomal frameshifting mechanism since the orf1a/orf1b overlapping nucleotide sequence is capable of inducing ribosomal frameshifting in vitro as well as in vivo. a stem-loop structure and a pseudoknot are pre ...19902159623
the e1 glycoprotein of an avian coronavirus is targeted to the cis golgi complex.it was previously reported that the e1 protein of an avian coronavirus was targeted to the juxtanuclear region in cos cells expressing the protein from cloned cdna, suggesting that the protein contains information for targeting to the golgi complex. the first of three membrane-spanning domains was required for intracellular targeting, because a mutant e1 (delta m1,2) lacking this domain was delivered to the plasma membrane. we have used immunoelectron microscopy to localize the wild-type e1 prot ...19902169615
amino acids within hypervariable region 1 of avian coronavirus ibv (massachusetts serotype) spike glycoprotein are associated with neutralization epitopes.the spike glycoprotein (s) gene of ibv codes for a precursor protein which is cleaved into the n-terminal s1 and c-terminal s2 glycopolypeptides. the s1 glycopolypeptide, which induces neutralizing antibody, comprises approximately 520 amino acid residues. we have determined the nucleotide sequence of s1 of seven strains of the massachusetts (mass) serotype and the first 337 bases of two additional mass strains. despite the fact that the strains had been isolated over three decades in europe and ...19882462314
phylogeny of antigenic variants of avian coronavirus ibv.the sequences of the peplomeric s1 protein of four serologically distinct strains of the infectious bronchitis virus (ibv), an avian coronavirus, have been determined. the s1 protein is thought to contain the serotype-specific neutralization epitopes and to be the main target of antigenic variation. an alignment with sequences of three strains published previously showed that from the 545 amino acid residues only 243 have been conserved. clustering of substitutions suggests that most serotype de ...19892466369
antigenicity of the peplomer protein of infectious bronchitis virus.to study the antigenic structure of the peplomer protein of the avian coronavirus infectious bronchitis virus, fragments from the peplomer gene were generated by restriction-enzyme cleavage or by limited dnase digestion and inserted in the escherichia coli expression plasmid pex (stanley and luzio, 1984). the antigenicity of the expression products was tested using a number of polyclonal antisera and monoclonal antibodies. the polyclonal antisera recognized different sets of epitopes in the 1162 ...19892467199
ultrastructure and protein a-gold immunolabelling of hrt-18 cells infected with turkey enteric coronavirus.the minnesota strain of turkey enteric coronavirus (tcv) was propagated in hrt-18 cells, a cell line derived from human rectum adenocarcinoma. a productive non-cytopathic infection was established, without a previous adaptation, in these cells as shown by the specific hemagglutinating activity in cell culture supernatants. a post-embedding immunochemical technique, using specific antiserum directed against the original egg-adapted virus and colloidal-gold-labelled protein a as the electron-dense ...19892548321
a specific transmembrane domain of a coronavirus e1 glycoprotein is required for its retention in the golgi region.the e1 glycoprotein of the avian coronavirus infectious bronchitis virus contains a short, glycosylated amino-terminal domain, three membrane-spanning domains, and a long carboxy-terminal cytoplasmic domain. we show that e1 expressed from cdna is targeted to the golgi region, as it is in infected cells. e1 proteins with precise deletions of the first and second or the second and third membrane-spanning domains were glycosylated, thus suggesting that either the first or third transmembrane domain ...19872821010
evolution of avian coronavirus ibv: sequence of the matrix glycoprotein gene and intergenic region of several serotypes.we have sequenced 200 to 240 bases of the matrix (m) glycoprotein gene of 23 strains of infectious bronchitis virus (ibv) representing the a (d207), b (d3896), c (d3128), d (d212), massachusetts (mass), uk11 and uk12 serotypes. the bases examined code for the external, hydrophilic region and the first membrane-embedded hydrophobic region of m, both regions comprising approximately 20 amino acids. as predicted from protein mr studies the a/d and b/c serotypes had two and one potential glycosylati ...19882832526
the nucleotide sequence of the extreme 5' end of the avian coronavirus genome; implications for the discontinuous mrna synthesis. 19863022236
rapid diagnosis by electron microscopy of avian coronavirus infection.the election microscopic examination of allantoic fluid from embryonated hens' eggs inoculated with tissue homogenates from organs of birds suffering with infectious bronchitis, reveals the presence of coronaviruses as early as the first or the second passage. this method permits a rapid diagnosis and is as accurate as the standard technique.19714260941
protective effect of an inactivated avian coronavirus vaccine administered by aerosol. 19734716970
replication and morphogenesis of avian coronavirus in vero cells and their inhibition by monensin.avian infectious bronchitis virus (ibv) was adapted to vero cells by serial passage. no significant inhibition of ibv replication was observed when infected vero cells were treated with alpha-amanitin or actinomycin d. in thin sections of infected cells, assembly of ibv was observed at the rough endoplasmic reticulum (rer), and mature ibv particles were located in dilated cisternae of the rer as well as in smooth cytoplasmic vesicles. in addition to typical ibv particles, enveloped particles con ...19846099655
sequence of the membrane protein gene from avian coronavirus ibv.cdna clones prepared from genomic rna of coronavirus ibv have been sequenced. the nucleotide sequence for the complete 5' region of mrna c, which is not present in mrnas a and b, has been determined. a sequence of 1224 bases is presented which contains a long open reading frame predicting a polypeptide of molecular weight 25 443. this is in agreement with the molecular weight of 23 000 reported for the unglycosylated form of the membrane polypeptide.19846099661
mouse hepatitis virus a59: mrna structure and genetic localization of the sequence divergence from hepatotropic strain mhv-3.the composition and structure of the mouse hepatitis virus (mhv)-specific rna in actinomycin d-treated, infected l-2 cells were studied. seven virus-specific rna species with molecular weights of 0.6 x 10(6), 0.9 x 10(6), 1.2 x 10(6), 1.5 x 10(6), 3.0 x 10(6), 4.0 x 10(6), and 5.4 x 10(6) (equivalent to the viral genome) were detected. t1 oligonucleotide fingerprinting studies suggested that the sequences of each rna species were totally included within the next large rna species. the oligonucle ...19816169842
coronavirus multiplication strategy. i. identification and characterization of virus-specified rna.we examined the synthesis of intracellular rna in primary chicken embryo kidney cells infected with the avian coronavirus infectious bronchitis virus. infected cells were labeled with (32)p(i) in the presence of actinomycin d for the duration of the viral multiplication cycle, and nucleic acids were extracted, denatured, and analyzed on agarose slab gels. six major rna species were found. none of these rnas was found in extracts of mock-infected cells. all six of the virus-specified rnas (design ...19806247505
the avian coronavirus multiplication strategy. 19816278881
structural analysis of virion proteins of the avian coronavirus infectious bronchitis virus.we have found six major polypeptides in virions of the avian coronavirus infectious bronchitis virus grown in tissue culture: four glycoproteins, gp84, gp36, gp31, and gp28, and two non-glycosylated proteins, p51 and p23. in addition, we detected three minor species: two glycoproteins, gp90 and gp59, and one non-glycosylated protein, p14. two-dimensional tryptic peptide mapping showed that gp36, gp31, gp28, and p23 comprise a group of closely related proteins which we have designated the "p23 fa ...19826283141
synthesis of coronavirus mrnas: kinetics of inactivation of infectious bronchitis virus rna synthesis by uv light.infection of cells with the avian coronavirus infectious bronchitis virus results in the synthesis of five major subgenomic rnas. these rnas and the viral genome form a 3' coterminal nested set. we found that the rates of inactivation of synthesis of the rnas by uv light were different and increased with the length of the transcript. these results show that each rna is transcribed from a unique promoter and that extensive processing of the primary transcripts probably does not occur.19826283182
coronavirus proteins: biogenesis of avian infectious bronchitis virus virion proteins.we examined the synthesis of viral structural proteins in cultured cells infected with the avian coronavirus infectious bronchitis virus. tryptic peptide mapping was used to determine the structural relationships of the intracellular proteins to the virion polypeptides. pulse-chase experiments were performed to identify precursors to the virus-specific proteins. we found that the nucleocapsid protein, p51, and the small viral membrane proteins gp31, gp28, and p23 do not undergo post-translationa ...19826294329
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 ...19826294330
coronavirus multiplication: locations of genes for virion proteins on the avian infectious bronchitis virus genome.six overlapping viral rnas are synthesized in cells infected with the avian coronavirus infectious bronchitis virus (ibv). these rnas contain a 3'-coterminal nested sequence set and were assumed to be viral mrnas. the seven major ibv virion proteins are all produced by processing of three polypeptides of ca. 23, 51, and 115 kilodaltons. these are the core polypeptides of the small membrane proteins, the nucleocapsid protein, and the 155-kilodalton precursor to the large membrane proteins gp90 an ...19846321790
characterization of a replicating and packaged defective rna of avian coronavirus infectious bronchitis virus.the beaudette strain of ibv was passaged 16 times in chick kidney 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 6. the defective rna, present in total cell extract rna and in oligo-(dt)30-selected rna from passage 15, was amplified b ...19948053152
oligomerization of a membrane protein correlates with its retention in the golgi complex.the first membrane-spanning domain (m1) of the m glycoprotein of avian coronavirus (formerly called e1) is sufficient to retain this protein in the cis-golgi. when the membrane-spanning domain of a protein which is efficiently delivered to the plasma membrane (vsv g protein) is replaced with m1, the resulting chimera (gm1) is retained in the golgi (swift, a. m., and c. e. machamer. 1991. j. cell biol. 115:19-30). when assayed in sucrose gradients, we observed that gm1 formed a large oligomer, an ...19938397214
retention of a cis golgi protein requires polar residues on one face of a predicted alpha-helix in the transmembrane domain.the first membrane-spanning domain (m1) of the model cis golgi protein m (formerly called e1) from the avian coronavirus infectious bronchitis virus is required for targeting to the golgi complex. when inserted in place of the membrane-spanning domain of a plasma membrane protein (vesicular stomatitis virus g protein), the chimeric protein ("gm1") is retained in the golgi complex of transfected cells. to determine the precise features of the m1 domain responsible for golgi targeting, we produced ...19938400455
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 ampl ...19958830542
replication and packaging of coronavirus infectious bronchitis virus defective rnas lacking a long open reading frame.the construction of a full-length clone of the avian coronavirus infectious bronchitis virus (ibv) defective rna (d-rna), cd-91 (9,080 nucleotides [z. penzes et al., virology 203:286-293]), downstream of the bacteriophage t7 promoter is described. electroporation of in vitro t7-transcribed cd-91 rna into ibv helper virus-infected primary chick kidney cells resulted in the production of cd-91 rna as a replicating d-rna in subsequent passages. three cd-91 deletion mutants were constructed--cd-44, ...19968970992
ceramide accumulation uncovers a cycling pathway for the cis-golgi network marker, infectious bronchitis virus m protein.the m glycoprotein from the avian coronavirus, infectious bronchitis virus (ibv), contains information for localization to the cis-golgi network in its first transmembrane domain. we hypothesize that localization to the golgi complex may depend in part on specific interactions between protein transmembrane domains and membrane lipids. because the site of sphingolipid synthesis overlaps the localization of ibv m, we asked whether perturbation of sphingolipids affected localization of ibv m. short ...19979396747
a common rna motif in the 3' end of the genomes of astroviruses, avian infectious bronchitis virus and an equine rhinovirus.in the 3' non-coding region of the genomes of infectious bronchitis virus, an avian coronavirus and the picornavirus equine rhinovirus serotype 2, there is a motif with remarkable similarity, both in sequence and folding, to the second rna stem-loop from the 3' end of the genomes of human astroviruses. this motif was also found in astroviruses of sheep, pig and turkey, suggesting that it is a common feature of all astroviruses. the conserved nature of the motif indicates that there has been stro ...19989568965
serotype identification of avian infectious bronchitis virus by rt-pcr of the peplomer (s-1) gene.the s-1 peplomer gene sequences of 31 strains of avian coronavirus infectious bronchitis virus (ibv) from north america, europe, and australia were compared to identify common and unique regions for possible diagnostic applications. s-1 sequences that were conserved among serotypes and sequences that were variable between serotypes were identified. based on conserved s-1 gene sequences, "general" degenerate oligonucleotide primers were designed that amplified ibv genomic rna by the reverse trans ...19989645318
the q-base of asparaginyl-trna is dispensable for efficient -1 ribosomal frameshifting in eukaryotes.the frameshift signal of the avian coronavirus infectious bronchitis virus (ibv) contains two cis-acting signals essential for efficient frameshifting, a heptameric slippery sequence (uuuaaac) and an rna pseudoknot structure located downstream. the frameshift takes place at the slippery sequence with the two ribosome-bound trnas slipping back simultaneously by one nucleotide from the zero phase (u uua aac) to the -1 phase (uuu aaa). asparaginyl-trna, which decodes the a-site codon aac, has the m ...200010623518
leader switching occurs during the rescue of defective rnas by heterologous strains of the coronavirus infectious bronchitis virus.a defective rna (d-rna), cd-61, derived from the beaudette strain of the avian coronavirus infectious bronchitis virus (ibv), was rescued (replicated and packaged) using four heterologous strains of ibv as helper virus. sequence analysis of the genomic rna from the four heterologous ibv strains (m41, h120, hv10 and d207) identified nucleotide differences of up to 17% within the leader sequence and up to 4.3% within the whole of the adjacent 5' untranslated region (utr). analysis of the 5' ends o ...200010675417
expression of reporter genes from the defective rna cd-61 of the coronavirus infectious bronchitis virus.the defective rna (d-rna) cd-61, derived from the beaudette strain of the avian coronavirus infectious bronchitis virus (ibv), was used as an rna vector for the expression of two reporter genes, luciferase and chloramphenicol acetyltransferase (cat). d-rnas expressing the cat gene were demonstrated to be capable of producing cat protein in a helper-dependent expression system to about 1.6 microgram per 10(6) cells. the reporter genes were expressed from two different sites within the cd-61 seque ...200010859373
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 effici ...200011086116
evidence of genetic diversity generated by recombination among avian coronavirus ibv.previously, we demonstrated that the de072 strain of ibv is a recombinant which has an ibv strain d1466-like sequence in the s gene. herein, we analyzed the remaining 3.8 kb 3' end of the genome, which includes gene 3, gene 4, gene 5, gene 6, and the 3' non-coding region of the de072 and d1466 strains. those two viruses had high nucleotide similarity in gene 4. however, the other individual genes had a much different level of sequence similarity with the same gene of the other ibv strains. the g ...200011087096
the missing link in coronavirus assembly. retention of the avian coronavirus infectious bronchitis virus envelope protein in the pre-golgi compartments and physical interaction between the envelope and membrane proteins.one missing link in the coronavirus assembly is the physical interaction between two crucial structural proteins, the membrane (m) and envelope (e) proteins. in this study, we demonstrate that the coronavirus infectious bronchitis virus e can physically interact, via a putative peripheral domain, with m. deletion of this domain resulted in a drastic reduction in the incorporation of m into virus-like particles. immunofluorescent staining of cells coexpressing m and e supports that e interacts wi ...200111278557
baculovirus expression of turkey coronavirus nucleocapsid protein.the nucleocapsid (n) gene of turkey coronavirus (tcv) was amplified by reverse transcriptase-polymerase chain reaction, cloned, and expressed in the baculovirus expression system. a recombinant baculovirus containing the tcv n gene (rbtcv/n) was identified by polymerase chain reaction and expression of tcv n protein as determined by western immunoblot analysis. two tcv-specific proteins, 52 and 43 kda, were expressed by rbtcv/n; one of these proteins, p52, was comparable in size to native tcv n ...200111332474
induction of caspase-dependent apoptosis in cultured cells by the avian coronavirus infectious bronchitis virus.avian coronavirus infectious bronchitis virus (ibv) is the causative agent of chicken infectious bronchitis, an acute, highly contagious viral respiratory disease. replication of ibv in vero cells causes extensive cytopathic effects (cpe), leading to destruction of the entire monolayer and the death of infected cells. in this study, we investigated the cell death processes during acute ibv infection and the underlying mechanisms. the results show that both necrosis and apoptosis may contribute t ...200111413307
further identification and characterization of novel intermediate and mature cleavage products released from the orf 1b region of the avian coronavirus infectious bronchitis virus 1a/1b polyprotein.the coronavirus 3c-like proteinase is one of the viral proteinases responsible for processing of the 1a and 1a/1b polyproteins to multiple mature products. in cells infected with avian coronavirus infectious bronchitis virus (ibv), three proteins of 100, 39, and 35 kda, respectively, were previously identified as mature cleavage products released from the 1b region of the 1a/1b polyprotein by the 3c-like proteinase. in this report, we show the identification of two more cleavage products of 68 a ...200111601893
reverse genetics system for the avian coronavirus infectious bronchitis virus.major advances in the study of the molecular biology of rna viruses have resulted from the ability to generate and manipulate full-length genomic cdnas of the viral genomes with the subsequent synthesis of infectious rna for the generation of recombinant viruses. coronaviruses have the largest rna virus genomes and, together with genetic instability of some cdna sequences in escherichia coli, this has hampered the generation of a reverse-genetics system for this group of viruses. in this report, ...200111711626
interaction of the coronavirus nucleoprotein with nucleolar antigens and the host cell.coronavirus nucleoproteins (n proteins) localize to the cytoplasm and the nucleolus, a subnuclear structure, in both virus-infected primary cells and in cells transfected with plasmids that express n protein. the nucleolus is the site of ribosome biogenesis and sequesters cell cycle regulatory complexes. two of the major components of the nucleolus are fibrillarin and nucleolin. these proteins are involved in nucleolar assembly and ribosome biogenesis and act as chaperones for the import of prot ...200211967337
molecular epizootiology of infectious bronchitis virus in sweden indicating the involvement of a vaccine strain.to improve the detection and molecular identification of infectious bronchitis virus (avian coronavirus), two reverse transcriptase-polymerase chain reaction (pcr) assays were developed. as 'diagnostic#10; pcr', a set of consensus nested primers was selected from highly conserved stretches of the nucleocapsid (n) gene. as 'phylogeny' pcr, a fragment of the spike protein gene (s1) was amplified and the pcr products were directly sequenced. to study the phylogenetic relationships of the viruses fr ...200212396345
in vitro and in ovo expression of chicken gamma interferon by a defective rna of avian coronavirus infectious bronchitis virus.coronavirus defective rnas (d-rnas) have been used for site-directed mutagenesis of coronavirus genomes and for expression of heterologous genes. d-rna cd-61 derived from the avian coronavirus infectious bronchitis virus (ibv) was used as an rna vector for the expression of chicken gamma interferon (chifn-gamma). d-rnas expressing chifn-gamma were shown to be capable of rescue, replication, and packaging into virions in a helper virus-dependent system following electroporation of in vitro-derive ...200312719562
[transgenic potato containing immunogenic gene of avian coronavirus and its immunogenicity in mice].to check the feasibility of expression of the immunogenic gene of avian coronavirus infectious bronchitis virus (ibv) in plants, the transformation of s1 gene of ibv into potato and the immunogenicity of its expression product was studied. the s1 gene of ibv-zj971 strain was inserted into plasmid pbi121 under the control of 35 s promoter. agrobacterium fumefaciens eha105 with the recombinant vector pbi121 was obtained by tri-parental mating method. so, an efficient potato transformation system m ...200314614539
generation of a recombinant avian coronavirus infectious bronchitis virus using transient dominant selection.a reverse genetics system for the avian coronavirus infectious bronchitis virus (ibv) has been described in which a full-length cdna, corresponding to the ibv (beaudette-ck) genome, was inserted into the vaccinia virus genome following in vitro assembly of three contiguous cdnas [casais, r., thiel, v., siddell, s.g., cavanagh, d., britton, p., 2001. reverse genetics system for the avian coronavirus infectious bronchitis virus. j. virol. 75, 12359-12369]. the method has subsequently been used to ...200515620403
gene 5 of the avian coronavirus infectious bronchitis virus is not essential for replication.the avian coronavirus infectious bronchitis virus (ibv), like other coronaviruses, expresses several small nonstructural (ns) proteins in addition to those from gene 1 (replicase) and the structural proteins. these coronavirus ns genes differ both in number and in amino acid similarity between the coronavirus groups but show some concordance within a group or subgroup. the functions and requirements of the small ns gene products remain to be elucidated. with the advent of reverse genetics for co ...200515956552
protecting human and ecological health under viral threats in asia.severe acute respiratory syndrome (sars) outbroke in 2003, and the avian influenza a (h5n1) also outbroke in 2003 and continued to 2004. these pandemic viral diseases originated in south east asia. many human and animal lives were lost. economic damages due to the pandemics were also very large. the question arises of why did the pandemics originate from south east asian areas. human influenza a consists of many sub-types of coronaviruses including the sars virus and the avian influenza (h5n1) t ...200516007933
selection of and recombination between minor variants lead to the adaptation of an avian coronavirus to primate cells.an interesting question posed by the current evidence that severe acute respiratory syndrome coronavirus may be originated from an animal coronavirus is how such an animal coronavirus breaks the host species barrier and becomes zoonotic. in this report, we study the chronological order of genotypic changes in the spike protein of avian coronavirus infectious bronchitis virus (ibv) during its adaptation to a primate cell line. adaptation of the beaudette strain of ibv from chicken embryo to vero ...200516137658
s1 gene characteristics and efficacy of vaccination against infectious bronchitis virus field isolates from the united states and israel (1996 to 2000).the s1 genes of isolates of avian coronavirus infectious bronchitis virus (ibv) from commercial chickens in the us and israel (20 isolates from each country) were studied using reverse transcription-polymerase chain reaction restriction fragment length polymorphism and sequencing. partial sequences spanning the amino terminus region of s1 from amino acid residues 48 to 219, based on the beaudette strain, were used for analysis. phylogenetic clustering and high-sequence identity values were used ...200516191702
subcellular localization of the severe acute respiratory syndrome coronavirus nucleocapsid protein.the coronavirus nucleocapsid (n) protein is a viral rna-binding protein with multiple functions in terms of virus replication and modulating cell signalling pathways. n protein is composed of three distinct regions containing rna-binding motif(s), and appropriate signals for modulating cell signalling. the subcellular localization of severe acute respiratory syndrome coronavirus (sars-cov) n protein was studied. in infected cells, sars-cov n protein localized exclusively to the cytoplasm. in con ...200516298975
the avian coronavirus infectious bronchitis virus undergoes direct low-ph-dependent fusion activation during entry into host cells.coronaviruses are the causative agents of respiratory disease in humans and animals, including severe acute respiratory syndrome. fusion of coronaviruses is generally thought to occur at neutral ph, although there is also evidence for a role of acidic endosomes during entry of a variety of coronaviruses. therefore, the molecular basis of coronavirus fusion during entry into host cells remains incompletely defined. here, we examined coronavirus-cell fusion and entry employing the avian coronaviru ...200616537586
cell cycle perturbations induced by infection with the coronavirus infectious bronchitis virus and their effect on virus replication.in eukaryotic cells, cell growth and division occur in a stepwise, orderly fashion described by a process known as the cell cycle. the relationship between positive-strand rna viruses and the cell cycle and the concomitant effects on virus replication are not clearly understood. we have shown that infection of asynchronously replicating and synchronized replicating cells with the avian coronavirus infectious bronchitis virus (ibv), a positive-strand rna virus, resulted in the accumulation of inf ...200616571830
the relationship of severe acute respiratory syndrome coronavirus with avian and other coronaviruses.in february 2003, a severe acute respiratory syndrome coronavirus (sars-cov) emerged in humans in guangdong province, china, and caused an epidemic that had severe impact on public health, travel, and economic trade. coronaviruses are worldwide in distribution, highly infectious, and extremely difficult to control because they have extensive genetic diversity, a short generation time, and a high mutation rate. they can cause respiratory, enteric, and in some cases hepatic and neurological diseas ...200617039827
heparan sulfate is a selective attachment factor for the avian coronavirus infectious bronchitis virus beaudette.the avian coronavirus infectious bronchitis virus (ibv) strain beaudette is an embryo-adapted virus that has extended species tropism in cell culture. in order to understand the acquired tropism of the beaudette strain, we compared the s protein sequences of several ibv strains. the beaudette strain was found to contain a putative heparan sulfate (hs)-binding site, indicating that the beaudette virus may use hs as a selective receptor. to ascertain the requirements of cell-surface hs for beaudet ...200717461266
lithium chloride inhibits the coronavirus infectious bronchitis virus in cell culture.the avian coronavirus infectious bronchitis virus (ibv) is a major economic pathogen of domestic poultry that, despite vaccination, causes mortality and significant losses in production. during replication of the rna genome there is a high frequency of mutation and recombination, which has given rise to many strains of ibv and results in the potential for new and emerging strains. currently the live-attenuated vaccine gives poor cross-strain immunity. effective antiviral agents may therefore be ...200717479370
trafficking motifs in the sars-coronavirus nucleocapsid protein.the severe acute respiratory syndrome-coronavirus nucleocapsid (n) protein is involved in virus replication and modulation of cell processes. in this latter respect control may in part be achieved through the sub-cellular localisation of the protein. n protein predominately localises in the cytoplasm (the site of virus replication and assembly) but also in the nucleus/nucleolus. using a combination of live-cell and confocal microscopy coupled to mutagenesis we identified a cryptic nucleolar loca ...200717524366
a massachusetts prototype like coronavirus isolated from wild peafowls is pathogenic to chickens.coronavirus infection was investigated in apparently healthy wild peafowls in guangdong province of china in 2003, while severe acute respiratory syndrome (sars) broke out there. no sars-like coronavirus had been isolated but a novel avian coronavirus strain, peafowl/gd/kq6/2003 (kq6), was identified. sequence analysis revealed that kq6 was an avian coronavirus infectious bronchitis virus (ibv), a member of coronavirus in group 3. the genome sequence of kq6 had extremely high degree of identity ...200717629993
the spike protein of infectious bronchitis virus is retained intracellularly by a tyrosine motif.we have analyzed the intracellular transport of the spike (s) protein of infectious bronchitis virus (ibv), an avian coronavirus. surface expression was analyzed by immunofluorescence microscopy, by surface biotinylation, and by syncytium formation by s-expressing cells. by applying these methods, the s protein was found to be retained intracellularly. tyr1143 in the cytoplasmic tail was shown to be a crucial component of the retention signal. deletion of a dilysine motif that has previously bee ...200818094153
coronavirus spike protein inhibits host cell translation by interaction with eif3f.in response to viral infection, the expression of numerous host genes, including predominantly a number of proinflammatory cytokines and chemokines, is usually up-regulated at both transcriptional and translational levels. it was noted that in cells infected with coronavirus, transcription and translation of some of these genes were differentially induced. drastic induction of their expression at the transcriptional level was observed in cells infected with coronavirus. however, induction of the ...200818231581
avian coronavirus infectious bronchitis attenuated live vaccines undergo selection of subpopulations and mutations following vaccination.in this study, we were interested in determining if high titered egg adapted modified live infectious bronchitis virus (ibv) vaccines contain spike gene related quasispecies that undergo selection in chickens, following vaccination. we sequenced the spike glycoprotein of 12 ibv vaccines (5 different serotypes from 3 different manufacturers) directly from the vaccine vial, then compared that sequence with reisolated viruses from vaccinated and contact-exposed birds over time. we found differences ...200818262691
proteolytic processing of polyproteins 1a and 1ab between non-structural proteins 10 and 11/12 of coronavirus infectious bronchitis virus is dispensable for viral replication in cultured cells.coronavirus 3c-like proteinase (3clpro) plays important roles in viral life cycle through extensive processing of the polyproteins 1a and 1ab into 12 mature, non-structural proteins (nsp5-nsp16). structural and biochemical studies have revealed that all confirmed 3clpro cleavage sites have a conserved gln residue at the p1 position, which is thought to be absolutely required for efficient cleavage. recent studies on murine hepatitis virus (mhv) showed that processing of the 1a polyprotein at the ...200818678384
rt-pcr detection of avian coronaviruses of galliform birds (chicken, turkey, pheasant) and in a parrot.of the many primer combinations that we have investigated for the detection of avian coronaviruses, two have worked better than any of the others: they worked with the largest number of strains/samples of a given coronavirus and the most species of avian coronavirus, and they also produced the most sensitive detection tests. the primer combinations were: oligonucleotide pair 2bp/4bm, which is in a region of gene 1 that is moderately conserved among all species of coronavirus (1); and utr11-/utr4 ...200819057865
transient dominant selection for the modification and generation of recombinant infectious bronchitis coronaviruses.we have developed a reverse genetics system for the avian coronavirus infectious bronchitis virus (ibv) in which a full-length cdna corresponding to the ibv genome is inserted into the vaccinia virus genome under the control of a t7 promoter sequence. vaccinia virus as a vector for the full-length ibv cdna has the advantage that modifications can be introduced into the ibv cdna using homologous recombination, a method frequently used to insert and delete sequences from the vaccinia virus genome. ...200819057872
a nomenclature for avian coronavirus isolates and the question of species status.currently, there is no agreed naming system for isolates of infectious bronchitis virus (ibv), whose host is the domestic fowl (gallus gallus domesticus). a uniform, informative system for naming ibv isolates would be very helpful. furthermore, the desirability of a single naming system has become more important with the recent discoveries that coronaviruses with genome organizations and gene sequences very similar to those of ibv have been isolated from turkeys (meleagris gallopavo) and pheasan ...200119184884
towards construction of viral vectors based on avian coronavirus infectious bronchitis virus for gene delivery and vaccine development.manipulation of the coronavirus genome to accommodate and express foreign genes is an attractive approach for gene delivery and vaccine development. by using an infectious cloning system developed recently for the avian coronavirus infectious bronchitis virus (ibv), the enhanced green fluorescent protein (egfp) gene, the firefly luciferase gene and several host and viral genes (eif3f, sars orf6, dengue virus 1 core protein gene) were inserted into various positions of the ibv genome, and the eff ...200919409420
acquisition of cell-cell fusion activity by amino acid substitutions in spike protein determines the infectivity of a coronavirus in cultured cells.coronavirus host and cell specificities are determined by specific interactions between the viral spike (s) protein and host cell receptor(s). avian coronavirus infectious bronchitis (ibv) has been adapted to embryonated chicken eggs, primary chicken kidney (ck) cells, monkey kidney cell line vero, and other human and animal cells. here we report that acquisition of the cell-cell fusion activity by amino acid mutations in the s protein determines the infectivity of ibv in cultured cells. express ...200919572016
the replicase gene of avian coronavirus infectious bronchitis virus is a determinant of pathogenicity.we have previously demonstrated that the replacement of the s gene from an avirulent strain (beaudette) of infectious bronchitis virus (ibv) with an s gene from a virulent strain (m41) resulted in a recombinant virus (beaur-m41(s)) with the in vitro cell tropism of the virulent virus but that was still avirulent. in order to investigate whether any of the other structural or accessory genes played a role in pathogenicity we have now replaced these from the beaudette strain with those from m41. t ...200919816578
avian coronavirus infectious bronchitis virus susceptibility to botanical oleoresins and essential oils in vitro and in vivo.anti-coronaviral activity of a mixture of oleoresins and essential oils from botanicals, designated qr448(a), was examined in vitro and in vivo. treatment of avian infectious bronchitis virus (ibv) with qr448(a) reduced the virus titer as measured in two laboratory host systems, vero e6 cells and embryonating eggs. the effect of qr448(a) on ibv in chickens was also investigated. administering qr448(a) to chickens at a 1:20 dilution by spray, 2h before challenge with ibv was determined to be the ...201020096315
identification of intertypic recombinant infectious bronchitis viruses from slaughtered chickens.avian coronavirus infectious bronchitis virus (ibv) poses a major threat to the global poultry industry. new ibv geno- and serotypes are continually reported. however, information on ibv prevalence is not frequently addressed in these reports. this study reports on a viral surveillance program in taiwan from 2005 to 2006 with sampling conducted in poultry slaughterhouses. the genetic features of the obtained field isolates were investigated using sequence analysis and simplot analysis. a 1-direc ...201020181858
differential sensitivity of well-differentiated avian respiratory epithelial cells to infection by different strains of infectious bronchitis virus.infectious bronchitis virus (ibv) is an avian coronavirus affecting the respiratory tract of chickens. to analyze ibv infection of the lower respiratory tract, we applied a technique that uses precision-cut lung slices (pclss). this method allows infection of bronchial cells within their natural tissue composition under in vitro conditions. we demonstrate that ibv strains 4/91, italy02, and qx infect ciliated and mucus-producing cells of the bronchial epithelium, whereas cells of the parabronchi ...201020538853
elucidation of the avian nucleolar proteome by quantitative proteomics using silac and changes in cells infected with the coronavirus infectious bronchitis virus.the nucleolus is a dynamic subnuclear compartment involved in ribosome subunit biogenesis, regulation of cell stress and modulation of cellular growth and the cell cycle, among other functions. the nucleolus is composed of complex protein/protein and protein/rna interactions. it is a target of virus infection with many viral proteins being shown to localize to the nucleolus during infection. perturbations to the structure of the nucleolus and its proteome have been predicted to play a role in bo ...201020827733
preparation and characterization of polyclonal antibody against severe acute respiratory syndrome-associated coronavirus spike protein.a truncated gene (designated s1) encoding the receptor-binding domain (rbd) in the spike (s) protein of severe acute respiratory syndrome-associated coronavirus (sars-cov) was amplified by pcr. the gene was cloned into prokaryotic expression vector pgex-6p-1, resulting in a recombinant plasmid pgex-sars-s1. subsequently, pgex-sars-s1 was transformed into host cells bl21(de3)plyss, and the expression of the s1 protein was induced by isopropyl β-d-thiogalactoside (iptg). polyclonal antibody agains ...201021087096
genetic diversity of avian infectious bronchitis virus isolated from domestic chicken flocks and coronaviruses from feral pigeons in brazil between 2003 and 2009.to detect the presence of infectious bronchitis virus or avian coronavirus, a nested reverse transcriptase pcr (rt-pcr) method was developed with the aim of amplifying a fragment of 530 bases, comprising the gene coding s1 protein. in the first step, all samples were submitted to rna extraction, rt-pcr, and nested pcr. next, only the positive nested-pcr samples were propagated in specific-pathogen-free (spf) embryonated chicken eggs for virus isolation. positive samples were then sequenced and a ...201021313839
attenuated live vaccine usage affects accurate measures of virus diversity and mutation rates in avian coronavirus infectious bronchitis virus.the full-length genomes of 11 infectious bronchitis virus (ibv) field isolates from three different types of the virus; massachusetts (mass), connecticut (conn) and california (cal) isolated over a 41, 25 and 8 year period respectively, were sequenced and analyzed to determine the mutation rates and level of polymorphisms across the genome. positive selection was not detected and mutation rates ranged from 10(-4) to 10(-6)substitutions/site/year for mass and conn ibv types where attenuated live ...201121539870
binding of avian coronavirus spike proteins to host factors reflects virus tropism and pathogenicity.the binding of viruses to host cells is the first step in determining tropism and pathogenicity. while avian infectious bronchitis coronavirus (ibv) infection and avian influenza a virus (iav) infection both depend on +¦2,3-linked sialic acids, the host tropism of ibv is restricted compared to that of iav. here we investigated whether the interaction between the viral attachment proteins and the host could explain these differences by using recombinant spike domains (s1) of ibv strains with diff ...201121697468
coronavirus nsp6 proteins generate autophagosomes from the endoplasmic reticulum via an omegasome intermediate.autophagy is a cellular response to starvation which generates autophagosomes to carry cellular organelles and long-lived proteins to lysosomes for degradation. degradation through autophagy can provide an innate defence against virus infection, or conversely autophagosomes can promote infection by facilitating assembly of replicase proteins. we demonstrate that the avian coronavirus, infectious bronchitis virus (ibv) activates autophagy. a screen of individual ibv non-structural proteins (nsps) ...201121799305
Changes in nonstructural protein 3 are associated with attenuation in avian coronavirus infectious bronchitis virus.Full-length genome sequencing of pathogenic and attenuated (for chickens) avian coronavirus infectious bronchitis virus (IBV) strains of the same serotype was conducted to identify genetic differences between the pathotypes. Analysis of the consensus full-length genome for three different IBV serotypes (Ark, GA98, and Mass41) showed that passage in embryonated eggs, to attenuate the viruses for chickens, resulted in 34.75-43.66% of all the amino acid changes occurring in nsp 3 within a virus typ ...201121909766
The sialic acid binding activity of the S protein facilitates infection by porcine transmissible gastroenteritis coronavirus.Transmissible gastroenteritis virus (TGEV) has a sialic acid binding activity that is believed to be important for enteropathogenicity, but that has so far appeared to be dispensable for infection of cultured cells. The aims of this study were to determine the effect of sialic acid binding for the infection of cultured cells under unfavorable conditions, and comparison of TGEV strains and mutants, as well as the avian coronavirus IBV concerning their dependence on the sialic acid binding activit ...201121910859
Avian coronavirus in wild aquatic birds.We detected a high prevalence (12.5%) of novel avian coronaviruses in aquatic wild birds. Phylogenetic analyses of these coronaviruses suggest that there is a diversity of gammacoronaviruses and deltacoronaviruses circulating in birds. Gammacoronaviruses were found predominantly in Anseriformes birds, whereas deltacoronaviruses could be detected in Ciconiiformes, Pelecaniformes, and Anseriformes birds in this study. We observed that there are frequent interspecies transmissions of gammacoronavir ...201121957308
Recombination in avian gamma-coronavirus infectious bronchitis virus.Recombination in the family Coronaviridae has been well documented and is thought to be a contributing factor in the emergence and evolution of different coronaviral genotypes as well as different species of coronavirus. However, there are limited data available on the frequency and extent of recombination in coronaviruses in nature and particularly for the avian gamma-coronaviruses where only recently the emergence of a turkey coronavirus has been attributed solely to recombination. In this stu ...201121994806
Modification of the avian coronavirus infectious bronchitis virus for vaccine development.Infectious bronchitis virus (IBV) causes an infectious respiratory disease of domestic fowl that affects poultry of all ages causing economic problems for the poultry industry worldwide. Although IBV is controlled using live attenuated and inactivated vaccines it continues to be a major problem due to the existence of many serotypes, determined by the surface spike protein resulting in poor cross-protection, and loss of immunogenicity associated with vaccine production. Live attenuated IBV vacci ...201222179147
up-regulation of mcl-1 and bak by coronavirus infection of human, avian and animal cells modulates apoptosis and viral replication.virus-induced apoptosis and viral mechanisms that regulate this cell death program are key issues in understanding virus-host interactions and viral pathogenesis. like many other human and animal viruses, coronavirus infection of mammalian cells induces apoptosis. in this study, the global gene expression profiles are first determined in ibv-infected vero cells at 24 hours post-infection by affymetrix array, using avian coronavirus infectious bronchitis virus (ibv) as a model system. it reveals ...201222253918
expression of the c-type lectins dc-sign or l-sign alters host cell susceptibility for the avian coronavirus, infectious bronchitis virus.infectious bronchitis virus (ibv), an avian coronavirus, is a cause of great economic loss in the poultry industry. the virus mainly infects respiratory epithelium, but can be also detected in other organs. the functional receptor for the virus has not been found and field strains of ibv do not infect conventional cell lines. recently, it has been shown that the c-type lectins dc-sign/l-sign can promote entry of several coronaviruses. here we examine whether dc-sign/l-sign are entry determinants ...201222340967
molecular evolution and emergence of avian gammacoronaviruses.coronaviruses, which are single stranded, positive sense rna viruses, are responsible for a wide variety of existing and emerging diseases in humans and other animals. the gammacoronaviruses primarily infect avian hosts. within this genus of coronaviruses, the avian coronavirus infectious bronchitis virus (ibv) causes a highly infectious upper-respiratory tract disease in commercial poultry. ibv shows rapid evolution in chickens, frequently producing new antigenic types, which adds to the multip ...201222609285
avian coronavirus spike glycoprotein ectodomain shows a low codon adaptation to gallus gallus with virus-exclusive codons in strategic amino acids positions.this is a study on the avian coronavirus ibv and chicken host-relationship from the codon usage point of view based on fifty-nine non-redundant ibv s1 sequences (nt 1-507) from strains detected worldwide and chicken tissue-specific protein genes sequences from ibv-replicating sites. the effective number of codons (enc) values ranged from 36 to 47.8, indicating a high-to-moderate codon usage bias. the highest ibv codon adaptation index (cai) value was 0.7, indicating a distant virus versus host s ...201222903606
complete genome sequences of two chinese virulent avian coronavirus infectious bronchitis virus variants.avian coronavirus infectious bronchitis virus (ibv) is variable, which causes many serotypes. here we reported the complete genome sequences of two virulent ibv variants from china, gx-yl5 and gx-yl9, belonging to different serotypes. differences between gx-yl5 and gx-yl9 were found mainly in stem-loop structure i in the predicted rna secondary structure of open reading frame (orf) 1b and the s protein gene fusion region, which will help us understand the molecular evolutionary mechanism of ibv ...201222966194
detection of avian coronavirus infectious bronchitis virus type qx infection in switzerland.infectious bronchitis, a disease of chickens caused by avian coronavirus infectious bronchitis virus (ibv), leads to severe economic losses for the poultry industry worldwide. various attempts to control the virus based on vaccination strategies are performed. however, due to the emergence of novel genotypes, an effective control of the virus is hindered. in 1996, a novel viral genotype named ibv-qx was reported for the first time in qingdao, shandong province, china. the first appearance of an ...201223051829
association of the chicken mhc b haplotypes with resistance to avian coronavirus.clinical respiratory illness was compared in five homozygous chicken lines, originating from homozygous b2, b8, b12 and b19, and heterozygous b2/b12 birds after infection with either of two strains of the infectious bronchitis virus (ibv). all chickens used in these studies originated from white leghorn and ancona linages. ibv gray strain infection of mhc homozygous b12 and b19 haplotype chicks resulted in severe respiratory disease compared to chicks with b2/b2 and b5/b5 haplotypes. demonstrati ...201323178407
demonstration of ornithobacterium rhinotracheale in pheasants (phasianus colchicus) with pneumonia and airsacculitis.outbreaks of respiratory disease were investigated in reared pheasants (phasianus colchicus) aged approximately 18 to 32 weeks, released into the semi-wild on four shooting estates in southern england. the clinical signs in the affected birds included swelling of the face and eyes, loss of condition, gasping respirations and coughing. the gross pathology findings included sinusitis, airsacculitis, pleural oedema and lung lesions. the histopathological findings in the affected lungs were characte ...201323581445
infectious bronchitis virus as a vector for the expression of heterologous genes.the avian coronavirus infectious bronchitis virus (ibv) is the causative agent of the respiratory disease infectious bronchitis of domestic fowl, and is controlled by routine vaccination. to explore the potential use of ibv as a vaccine vector a reverse genetics system was utilised to generate infectious recombinant ibvs (ribvs) expressing the reporter genes enhanced green fluorescent protein (egfp) or humanised renilla luciferase (hrluc). infectious ribvs were obtained following the replacement ...201323840781
simultaneous detection of five major serotypes of avian coronavirus by a multiplex microsphere-based assay.avian coronavirus (commonly known as infectious bronchitis virus [ibv]) is of major economic importance to commercial chicken producers worldwide. due to the existence of multiple serotypes and variants of the virus that do not cross-protect, it is important to diagnose circulating serotypes and choose the right vaccine type for successful protection. in an effort to improve conventional diagnostic tests, a microsphere-based assay was developed and evaluated for simultaneous detection of the mos ...201323847226
cell-mediated immune responses in the head-associated lymphoid tissues induced to a live attenuated avian coronavirus vaccine.humoral immunity is important for controlling viral diseases of poultry, but recent studies have indicated that cytotoxic t cells also play an important role in the immune response to infectious bronchitis virus (ibv). to better understand the cell mediated immune responses to ibv in the mucosal and systemic immune compartments chickens were ocularly vaccinated with ibv. this induced a lymphocyte expansion in head-associated lymphoid tissues (halt) and to a lesser extent in the spleen, followed ...201323948147
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