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PubMedDate not supplied

Comparison of serological tests for antibodies against Newcastle disease virus and infectious bronchitis virus using ImmunoComb solid-phase immunoassay, a commercial enzyme-linked immunosorbent assay, and the hemagglutination-inhibition assay.

COMBSCORES determined using the ImmunoComb solid-phase immunoassay were compared with hemagglutination-inhibition (HI) titers specific for Newcastle disease virus (NDV) and infectious bronchitis virus (IBV) and with mean enzyme-linked immunosorbent assay (ELISA) titers determined using Agritech Systems, Inc., ELISA. COMBSCORES for NDV and IBV increased proportionately in a stepwise manner as HI titers increased. The ImmunoComb solid-phase immunoassay was ablt to produce endpoint titers on sera with NDV-HI titers of 0 through 320 and IBV-HI titers of 0 through 1024 without reaching the maximum S-value. The ImmunoComb showed good correlation with the HI assay and the Agritech ELISA and should prove to be a useful tool for serological profiling, either alone or in conjunction with the HI test or commercial ELISA.

Animals↗
PubMedDate not supplied

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

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

Antibodies, Viral↗
PubMed2003

Memory T cells protect chicks from acute infectious bronchitis virus infection.

Infectious bronchitis has remained one of the most difficult to control diseases in poultry since it was first described in 1931. Previous studies demonstrated that primary CD8(+) T lymphocytes collected at 10 days post-infection (p.i.) are important in controlling acute infection. To further investigate the role of memory T cells in protection, T lymphocytes collected from B19/B19 chicken spleens at 2, 3, 4, and 6 weeks p.i. were transferred to six-day-old syngeneic chicks one day prior to challenging with 10(6) EID(50) of the IBV Gray strain. Memory immune T cells collected at 3 to 6 weeks p.i. provided dose responsive protection from clinical illness. The greatest protection was observed after the transfer of 10(7) T cells collected at 6 weeks p.i., whereas T cells collected at 2 weeks p.i. did not protect. Annexin-V staining of the spleen cells demonstrated that the cells collected at 2 weeks p.i. were undergoing significantly more apoptosis than cells collected at 10 days p.i. Specific antibody production in sera collected at 7 days p.i. did not correlate with protection. T cell subtype depletion demonstrated that CD8(+), not CD4(+), T cells were critical. Memory T cells can be detected in peripheral blood mononuclear cells up to at least 10 weeks p.i. These results demonstrated that IBV specific CD8(+) memory T cells generated at 3 to 6 weeks p.i. can protect syngeneic chicks from acute IBV infection.

Animals↗
PubMed1992

Recent studies on the enterotropic strain of avian infectious bronchitis virus.

Avian infectious bronchitis (AIB) is an economically important disease of chickens. Recent studies have revealed enterotropism by at least one strain of AIB virus with pathological lesions in parts of the gut. This review highlights the findings of the studies so far made on this enterotropic strain of AIB virus.

Animals↗
PubMed2000

Effect of liquid paraffin on antibody responses and local adverse reactions of bivalent oil adjuvanted vaccines containing newcastle disease virus and infectious bronchitis virus.

Effects of liquid paraffin on antibody responses and local adverse reactions after intramuscular injection of oil adjuvanted vaccines containing Newcastle disease (ND) and infectious bronchitis (IB) virus were investigated in chickens. Each vaccine was prepared with a liquid paraffin such as Carnation, Crystol 52 and Lytol. These vaccines induced sustained antibody responses against ND and IB. Among local adverse reactions, Lytol induced granulomatous reactions and abscesses, but Carnation and Crystol 52 did not. The residual weight of liquid paraffin at the injection site decreased in the order Carnation, Crystol 52, Lytol. Crystol 52 was composed of relatively few short-chain hydrocarbons (i.e., n-C20H42). The vaccine with liquid paraffin mainly composed of n-C16H34-n-C20H42 was suggested to induce fewer adverse reactions.

Adjuvants, Immunologic↗
PubMed2001

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 to the death of infected cells in lytic IBV infection. Caspase-dependent apoptosis, as characterized by chromosomal condensation, DNA fragmentation, caspase-3 activation, and poly(ADP-ribose) polymerase degradation, was detected in IBV-infected Vero cells. Addition of the general caspase inhibitor z-VAD-FMK to the culture media showed inhibition of the hallmarks of apoptosis and increase of the release of virus to the culture media at 16 h postinfection. However, neither the necrotic process nor the productive replication of IBV in Vero cells was severely affected by the inhibition of apoptosis. Screening of 11 IBV-encoded proteins suggested that a 58-kDa mature cleavage product could induce apoptotic changes in cells transiently expressing the protein. This study adds one more example to the growing list of animal viruses that induce apoptosis during their replication cycles.

Amino Acid Chloromethyl Ketones↗
PubMed1977

Studies on the structure of a coronavirus-avian infectious bronchitis virus.

When avian infectious bronchitis virus (IBV) is fixed in formaldehyde, negative stain is able to penetrate the particle and an internal component is visualized. This component is seen as a tongue or flask shaped structure attached at one point to the outer virus membrane. A model yielding transmission patterns similar to the virus has been made. Gradient centrifugation studies on IBV reveal that the RNP is associated with the internal sac.

Coronaviridae↗
PubMed1977

Polypeptides of the surface projections and the ribonucleoprotein of avian infectious bronchitis virus.

Purified avian infectious bronchitis virus was digested with bromelain (0.7 mg/ml), and the surface projections were removed. Polyacrylamide gel electrophoresis of the polypeptides from these bromelain-treated particles showed that VP1, VP2, and VP5 were missing from the seven polypeptides. VP1 to VP7, that were present in untreated virus preparations. Milder bromelain treatment (0.07 mg/ml) left visible surface projections and polypeptides comprising VP1 and VP2 intact, but removed VP5. Thus, there are apparently two types of surface projections on the virus particle. The ribonucleoprotein complex was released from virus particles disrupted with 1% Nonidet P-40. The proportion of VP6 in such preparations was greatly reduced, implying that VP6 is the structural polypeptide of the ribonucleoprotein. Polypeptides VP1, VP2, VP4, and VP5 are glycosylated, but none of the polypeptides contains lipid.

Bromelains↗
PubMed1986

Chicken embryonal vaccination with avian infectious bronchitis virus.

A commercial infectious bronchitis virus (IBV) vaccine of the Massachusetts 41 strain was injected in embryonating chicken eggs on embryonation day (ED) 18. The IBV vaccine was pathogenic for embryos, and it was passaged in chicken kidney tissue culture to reduce the pathogenicity. At the 40th tissue culture passage (P40-IBV), the virus became apathogenic for the embryos. Maternal antibody-positive or -negative chicks hatching from eggs injected with P40-IBV developed antibody to IBV and were protected against challenge exposure at 4 weeks of age with virulent Massachusetts 41 IBV. Although P40-IBV protected chicks when administered on ED 18, this virus did not protect chicks well if given at hatch. When combined with the turkey herpesvirus (HVT), P40-IBV given on ED 18 did not interfere with the protection against challenge exposure with virulent Marek's disease virus, nor did the presence of HVT interfere with protection by P40-IBV. Thus, under laboratory conditions, IBV vaccine could be combined with HVT to form a bivalent embryonal vaccine.

Animals↗
PubMed2000

Relationship between serotypes and genotypes based on the hypervariable region of the S1 gene of infectious bronchitis virus.

To group infectious bronchitis virus (IBV) isolates, a genetic grouping method based on hypervariable region 1 (HVR 1, nucleotides 168 to 197) was compared with that based on the whole S1 gene. Both methods resulted in the same grouping data. So the grouping method based on HVR 1 could represent the grouping method based on the whole S1 gene. Taiwan isolates could not be placed within the existing groups. In order to test the correlation between genotype and serotype, a one-way neutralization test was used to compare 9 Taiwan isolates selected from different genotypes with Massachusetts (Mass) (H120) and Connecticut (Conn) standard strains. In addition, a two-way cross-neutralization test was performed in embryonated eggs with the beta method (constant-virus, diluted-serum) and the reciprocal neutralization titers were calculated to give the relatedness (r) values. The results of two kinds of neutralizing tests showed that the serotypes of 9 isolates were different from Mass or Conn. Based on the r-values, 9 isolates were divided into two serotypes which were correlated with their genotypes. From pathogenicity tests, IBV Taiwan isolates could be divided into high, intermediate, and low pathogenicity according to their pathogenicity indexes. However, no relationship exists between pathotype and genotype. In conclusion, the genetic typing method based on HVR 1 can be used for typing IBV isolates.

Animals↗
PubMed2006

Preliminary crystallographic analysis of avian infectious bronchitis virus main protease.

Infectious bronchitis virus (IBV) is the prototype of the genus Coronavirus. It causes a highly contagious disease which affects the respiratory, reproductive, neurological and renal systems of chickens, resulting great economic losses in the poultry industry worldwide. The coronavirus (CoV) main protease (M(pro)), which plays a pivotal role in viral gene expression and replication through a highly complex cascade involving the proteolytic processing of replicase polyproteins, is an attractive target for antiviral drug design. In this study, IBV M(pro) was overexpressed in Escherichia coli. Crystals suitable for X-ray crystallography have been obtained using microseeding techniques and belong to space group P6(1)22. X-ray diffraction data were collected in-house to 2.7 A resolution from a single crystal. The unit-cell parameters were a = b = 119.1, c = 270.7 A, alpha = beta = 90, gamma = 120 degrees. Three molecules were predicted to be present in the asymmetric unit from a calculated self-rotation function.

Animals↗
PubMed2001

Nucleocapsid protein gene sequence analysis reveals close genomic relationship between turkey coronavirus and avian infectious bronchitis virus.

Antibodies to infectious bronchitis virus (IBV) cross-react with turkey coronavirus (TCV) in immunofluorescence assay (IFA) indicating that IBV and TCV may share an amino acid sequence similarity. To determine its extent, the gene encoding the nucleocapsid (N) protein of TCV was amplified by reverse transcription-PCR (RT-PCR) from RNA purified from intestines of embryos of turkeys infected with various TCV isolates and from allantoic fluid of chicken embryos infected with IBV M41 strain, the obtained N genes were cloned, sequenced and compared with known sequences of N genes of five IBV strains. The primers for amplification were designed from the genome of IBV PCR products were obtained only from two of eight TCV isolates tested. It was found that the two TCV isolates were identical with five IBV strains by 90.1-94.1% at the N gene level. It was also observed that the N gene of eight TCV isolates originating from various regions of the USA could not be amplified by the primers designed from the N gene of bovine coronavirus (BCV).

Amino Acid Sequence↗
PubMedDate not supplied

Evaluation of the hemagglutination-inhibition test for measuring the response of chickens to avian infectious bronchitis virus vaccination.

An infectious bronchitis virus (IBV) hemagglutination-inhibition (HI) test was used to assay serum-antibody titers after IBV vaccination of IBV-susceptible specific-pathogen-free broilers and commercial layers. Three-week-old broilers were vaccinated via eye-drop with IBV strains that represent the antigenic spectrum of commercial vaccines--Holland, Massachusetts 41 (41 Ms), Connecticut 46, Florida 18288, or JMK strain--and revaccinated 3 weeks later with either the same or a heterologous strain. Weekly serum samples were tested by IBV HI with homologous and heterologous antigens. Vaccinates, except for those vaccinated with the Holland strain, were HI-positive with homologous but not heterologous antigens by 1 to 2 weeks postvaccination. Sixteen-week-old IBV-vaccinated commercial layers were revaccinated with IBV Holland 52 (H 52) strain and subsequently infected with Arkansas 99 (Ark 99) and SE 17 strains. In contrast to the limited HI cross-reactivity of serum from IBV-vaccinated broilers, there were extensive cross-reactions in HI tests with 41 Ms, H 52, Ark 99, and SE 17 antigens of revaccinated layers. These results demonstrate that the IBV HI test is more strain-specific than previous reports indicate, especially when the test samples are from early postvaccination.

Animals↗