Comparison between dot-immunoblotting assay and clinical sign determination method for quantifying avian infectious bronchitis virus vaccine by titration in embryonated eggs.
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ABSTRACT:
SUBMITTER: Yuk SS
PROVIDER: S-EPMC7119534 | biostudies-literature | 2016 Apr
REPOSITORIES: biostudies-literature
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Project description:Avian infectious bronchitis (IB) is caused by avian infectious bronchitis virus (IBV) belonging to Coronaviridae family. The disease is prevalent in all countries with almost 100% incidence rate. Chicken and commercially reared pheasant are the natural host for IBV. Virus causes respiratory diseases, poor weight gain, feed efficiency in broiler, damage to oviduct, and abnormal egg production in mature hens resulting in economic losses. IBV also replicates in tracheal and renal epithelial cells leading to prominent tracheal and kidney lesions. Virus undergoes spontaneous mutation leading to continual emergence of new variants. The effectiveness of immunization program is diminished because of poor cross-protection among the serotypes. Identification of circulating serotypes is important in controlling IBV infection. Toll-like receptor 3 (TLR3) and TLR21 are involved in early recognition of virus resulting in induction of inflammatory cytokines. Both humoral and cellular immune responses are important in the control of infection. Humoral immunity plays an important role in recovery and clearance of viral infection. IBV-specific cytotoxic T lymphocytes induce lysis of IBV-infected cells. Effective diagnostic tools are required at field level to identify different IBV variants. Embryonated chicken eggs are effective model for virus isolation. Identification by other specific methods like virus neutralization (VN), hemagglutination inhibition (HI), enzyme linked immunosorbent assay (ELISA), immunohistochemistry, or nucleic acid analysis or by electron microscopy is also indispensable. VN test in tracheal organ culture is the best method for antigenic typing for surveillance purposes. Continuous epidemiological surveillance, strict biosecurity measures, and vaccine effective against various serotypes are necessary for controlling IB in chickens.
| S-EPMC7120852 | biostudies-literature
Project description:A rapid and sensitive method for the detection and unambiguous typing of infectious bronchitis virus (IBV) is described. RNA was isolated from IBV-infected allantoic fluid and was transcribed into cDNA. This cDNA was amplified by the polymerase chain reaction. The polymerase chain reaction products were subsequently analyzed on an agarose gel. The presence of IBV-specific RNA in the allantoic fluid then allowed the amplification of a 438-bp DNA fragment from the nucleocapsid (N) gene. For the typing of IBV isolates, we used amplified double-stranded DNA as a template in a sequencing reaction. We report 360 bases of the N gene of 18 IBV isolates. The sequence of the N gene was different between serologically indistinguishable IBV strains and may be a valuable tool in epidemiologic studies. A phylogenetic tree that was based on the sequences obtained did not agree with trees that were based on other parts of the sequence, illustrating the high frequency of recombination between IBV strains.
| S-EPMC265000 | biostudies-other
Project description:Avian infectious bronchitis (IB) is an acute, highly infectious and contagious viral disease of chickens caused by avian infectious bronchitis virus (IBV) belonging to the genus Coronavirus and family Coronaviridae. It can affect all age groups of birds. The toll-like receptors (TLRs) are a major class of innate immune pattern recognition receptors that have a key role in immune response and defense against various infections.The TLRs are essential for initiation of innate immune responses and in the development of adaptive immune responses. An in ovo model was employed to study the antiviral activity of TLR ligands (Pam3CSK4, LPS and CpG ODN) on replication of IBV. It was hypothesized that optimum dose and specific timing of TLR ligands may reduce viral load of IBV in specific pathogen free (SPF) embryonated chicken eggs (ECEs). Further, the mechanism involved in the TLR-mediated antiviral response in chorioallantoic membrane (CAM) of ECEs was investigated. The ECEs of 9-11 days old were treated with different doses (high, intermediate and low) of TLR-2 (Pam3CSK4), TLR-4 (LPS) and TLR-21 (CpG ODN) ligands. In addition, to know the timing of TLR ligand treatment, six time intervals were analyzed viz. 36, 24 and 12?h prior to infection, time of infection (co-administration of TLR ligands and avian IBV) and 12 and 24?h post-IBV infection. For studying the relative expression of immuno-stimulatory genes (IFN-?, IFN-?, IFN-?, IL-1?, iNOS and OAS) in CAM, TLR ligands were administered through intra-allantoicroute and CAM were collected at 4, 8 and 16?h post treatment. The results demonstrated that intermediate dose of all the three TLR ligands significantly reduced virus titers and used in the present study. However, the LPS reduced virus titer pre- and post-IBV infection but Pam3CSK4 and CpG ODN reduced only pre-IBV infection. Further analysis showed that TLR ligands induced IFN-?, IL-1? and IFN stimulated genes viz. iNOS and OAS genes in CAM. The present study pointed towards the novel opportunities for rational design of LPS as immuno-stimulatory agent in chickens with reference to IBV. It may be speculated that in ovo administration of these TLR ligands may enhance resistance against viral infection in neonatal chicken and may contribute towards the development of more effective and safer vaccines including in ovo vaccines.
| S-EPMC7112572 | biostudies-literature
Project description: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 study, the full-length genomes of eight avian gamma-coronavirus infectious bronchitis virus (IBV) isolates were sequenced and along with other full-length IBV genomes available from GenBank were analyzed for recombination. Evidence of recombination was found in every sequence analyzed and was distributed throughout the entire genome. Areas that have the highest occurrence of recombination are located in regions of the genome that code for nonstructural proteins 2, 3 and 16, and the structural spike glycoprotein. The extent of the recombination observed, suggests that this may be one of the principal mechanisms for generating genetic and antigenic diversity within IBV. These data indicate that reticulate evolutionary change due to recombination in IBV, likely plays a major role in the origin and adaptation of the virus leading to new genetic types and strains of the virus.
| S-EPMC3187689 | biostudies-literature
Project description:Infectious bronchitis virus (IBV) is a positive-sense, single-stranded, enveloped RNA virus responsible for substantial economic losses to the poultry industry worldwide by causing a highly contagious respiratory disease. The virus can spread quickly through contact, contaminated equipment, aerosols, and personal-to-person contact. We highlight the prevalence and geographic distribution of all nine genotypes, as well as the relevant symptoms and economic impact, by extensively analyzing the current literature. Moreover, phylogenetic analysis was performed using Molecular Evolutionary Genetics Analysis (MEGA-6), which provided insights into the global molecular diversity and evolution of IBV strains. This review highlights that IBV genotype I (GI) is prevalent worldwide because sporadic cases have been found on many continents. Conversely, GII was identified as a European strain that subsequently dispersed throughout Europe and South America. GIII and GV are predominant in Australia, with very few reports from Asia. GIV, GVIII, and GIX originate from North America. GIV was found to circulate in Asia, and GVII was identified in Europe and China. Geographically, the GVI-1 lineage is thought to be restricted to Asia. This review highlights that IBV still often arises in commercial chicken flocks despite immunization and biosecurity measures because of the ongoing introduction of novel IBV variants and inadequate cross-protection provided by the presently available vaccines. Consequently, IB consistently jeopardizes the ability of the poultry industry to grow and prosper. Identifying these domains will aid in discerning the pathogenicity and prevalence of IBV genotypes, potentially enhancing disease prevention and management tactics.
| S-EPMC10875066 | biostudies-literature
Project description:Vaccines constitute a unique selective pressure, different from natural selection, drives the evolution of influenza virus. In this study, A/Chicken/Shanghai/F/1998 (H9N2) was continually passaged in specific pathogen-free embryonated chicken eggs with or without selective pressures from antibodies induced by homologous maternal antibodies. Genetic mutations, antigenic drift, replication, and pathogenicity of the passaged virus were evaluated.Antigenic drift of the passaged viruses occurred in the 47th generation (vF47) under selective pressure on antibodies and in the 52nd generation (nF52) without selective pressure from antibodies. Seven mutations were observed in the vF47 virus, with three in PB2 and four in HA, whereas 12 mutations occurred in the nF52 virus, with three in PB2, two in PB1, four in HA, one in NP, one in NA, and one in NS. Remarkably, the sequences of the HA segment from vF47 were 100% homologous with those of the nF52 virus. Both the vF47 and nF52 viruses showed enhanced replication compared to the parental virus F/98, but higher levels of replication and pathogenicity were displayed by nF52 than by vF47. An inactive vaccine derived from the parental virus F/98 did not confer protection against challenges by either the vF47 or nF52 virus, but inactive vaccines derived from the vF47 or nF52 virus were able to provide protection against a challenge using F/98.Taken together, the passage of H9N2 viruses with or without selective pressure of the antibodies induced by homologous maternal antibodies showed genetic variation, enhanced replication, and variant antigenicity. Selective pressure of the antibody does not seem to play a key role in antigenic drift in the egg model but may impact the genetic variation and replication ability of H9N2 viruses. These results improve understanding of the evolution of the H9N2 influenza virus and may aid in selecting appropriate vaccine seeds.
| S-EPMC5840701 | biostudies-literature
Project description:Background & objectives:The susceptibility of influenza viruses to neuraminidase inhibitors (NAIs) is studied using enzyme-based assays, sequence analysis and in vitro and in vivo studies. Oseltamivir carboxylate (OC) is the active prodrug of the NAI oseltamivir. There is lack of information on the use of embryonated chicken eggs for studying susceptibility of highly pathogenic avian influenza (HPAI) H5N1 viruses to antiviral drugs. The aim of the present study was to assess the use of 10 day old embryonated chicken eggs for studying antiviral susceptibility of HPAI H5N1 viruses. Methods:Two HPAI H5N1 viruses isolated from India were used in the study. Fluorescence-based NAI assay was performed to determine antiviral susceptibility of these viruses. In ovo antiviral assays were carried out using 10 day old embryonated chicken eggs. The virus dilutions were incubated with 14 ?g/ml of OC and inoculated in the allantoic cavity. In the eggs, 50 per cent egg infectious dose (EID50) titres as well as mortality were quantitated. Results:The two viruses used were susceptible to OC in the NAI assay. It was found that there was a significant drop in EID50titres; however, no significant protection from mortality after OC treatment was observed. Interpretation & conclusions:By measuring viral titres, the egg model was suitable to study the susceptibility of HPAI viruses to antiviral drugs along with NAI assay. The present study highlights the use of eggs as a model to study susceptibility of HPAI viruses to OC.
| S-EPMC6977371 | biostudies-literature
Project description:Background:Infectious bronchitis virus (IBV) is the etiological agent of an acute and highly contagious disease. Infectious bronchitis (IB) affects chicken of all ages and poses major economic loses to the poultry industry worldwide. The continuous evolution of the spike protein (S1) of IBV is responsible for the prevalence of many serotypes/genotypes around the world. Multiple lineages of IBV strains have been detected in chicken flocks in India since 2003. Aims:To detect IBV genotypes prevalent in India. Methods:Organ samples from 20 IBV-positive flocks with variable clinical signs were used for the amplification of the S1 gene of IBV by reverse transcriptase-polymerase chain reaction (RT-PCR). Results:Positive PCR amplicons were sequenced. Sequence analysis showed that 14 field isolates belonged to the GI-1 genetic lineage (Mass 41 serotype), two field isolates belonged to the GI-13 (UK 4/91 variant IBV strain), one field isolate grouped with GIII, GV, and GVI genetic lineage and three belonged to a variant genotype unique to India (GI-24). Phylogenetic analysis also showed a similar type of grouping within the field isolates. Among the fourteen GI-1 isolates, 12 were isolated between 2003 and 2006 and only two were isolated between 2009 and 2011. The two field isolates belonging to GI-13 were isolated in 2007, another one belonging to GIII, GV, and GVI was isolated in 2010 and three field isolates were not close to any reference IBV sequences isolated in 2006 (IND-TN-168-06), 2010 (IND-TN-280-10) and 2011 (IND-TN-290-11). Conclusion:A unique variant of IBV is emerging in India (GI-24). Our findings will have important implications for future vaccine intervention.
| S-EPMC7183371 | biostudies-literature
Project description:A virulent avian infectious bronchitis virus (IBV) was isolated from 30-day-old broiler chickens that exhibited respiratory symptoms, nephropathologic lesions, and a high proportion of deaths in the People's Republic of China during 2005. The strain, designated YN, was genetically and pathologically characterized. Phylogenetic analysis showed that YN and most of the previously characterized IBV isolates found in China were phylogenetically classified into 2 main genetic clusters. The YN isolate caused severe lesions and resulted in deaths of 65% in experimental infections of 30-day-old specific-pathogen-free chickens. Tracheal and severe kidney lesions developed in all infected birds, confirming the ability of YN strain to induce both respiratory and renal disease. IBV antigens were detected by immunohistochemical analysis in the trachea, lung, kidney, and bursa, consistent with histopathologic observations, virus isolation, and reverse transcription PCR detection. We showed that YN IBV exhibits severe pathogenicity in chickens, and that similar viruses are prevalent in China.
| S-EPMC3557894 | biostudies-literature
Project description:Avian infectious bronchitis virus (IBV) infection is one of the major viral respiratory diseases of chickens. Better understanding of the molecular basis of viral pathogenesis should contribute significantly towards the development of improved prophylactic, therapeutic and diagnostic reagents to control infections. In the present investigation, transcriptional profiles were analyzed by using RNA recovered from the lung tissue of IBV infected 18-day-old chicken embryos at 6, 24, 48 and 72 h post IBV infection. This microarray analysis was completed using avian cDNA arrays comprised of fragments of 1191 unique chicken and turkey gene transcripts. These arrays were generated from normalized cDNA subtraction libraries that were derived from avian pneumovirus (APV) infected chicken embryo fibroblast (CEF) cultures and tissues obtained from APV infected turkeys subtracted with their respective uninfected cultures and tissues. Of the 1191 unique genes represented on the array, the expression of a total of 327 genes (27% of total) were altered by two-fold or more from 6 through 72 h post-infection. A comparative analysis of IBV regulated genes with genes previously reported to change in expression following infection with other avian respiratory viruses revealed both conserved and unique changes. Real-time qRT-PCR was used to confirm the regulated expression of genes related to several functional classes including kinases, interferon induced genes, chemokines and adhesion molecules, vesicular trafficking and fusion protein genes, extracellular matrix protein genes, cell cycle, metabolism, cell physiology and development, translation, RNA binding, lysosomal, protein degradation and ubiquitination related genes. Microarray analysis served as an efficient tool in facilitating a comparative analysis of avian respiratory viral infections and provided insight into host transcriptional changes that were conserved as well as those which were unique to individual pathogens.
| S-EPMC7114260 | biostudies-literature