scholarly journals Triplet amino acids located at positions 145/146/147 of the RNA polymerase of very virulent infectious bursal disease virus contribute to viral virulence

2014 ◽  
Vol 95 (4) ◽  
pp. 888-897 ◽  
Author(s):  
Li Gao ◽  
Kai Li ◽  
Xiaole Qi ◽  
Honglei Gao ◽  
Yulong Gao ◽  
...  
Keyword(s):  
Amino Acids ◽  
Glutamic Acid ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Chicken Embryo Fibroblast ◽  
Critical Role ◽  
Infectious Bursal Disease ◽  
Effective Prevention ◽  
Viral Virulence ◽  
Bursal Disease

Infectious bursal disease virus (IBDV) causes an economically significant disease of chickens worldwide. The emergence of very virulent IBDV (vvIBDV) has brought more challenges for effective prevention of this disease. The molecular basis for the virulence of vvIBDV is not fully understood. In this study, 20 IBDV strains were analysed phylogenically and clustered in three branches based on their full-length B segments. The amino acid triplet located at positions 145/146/147 of VP1 was found highly conserved in branch I non-vvIBDVs as asparagine/glutamic acid/glycine (NEG), in branch II vvIBDVs as threonine/glutamic acid/glycine (TEG) and in branch III vvIBDVs as threonine/aspartic acid/asparagine (TDN). Further studies showed that the three amino acids play a critical role in the replication and pathogenicity of vvIBDV. Substitution of the TDN triplet with TEG or NEG reduced viral replication and pathogenicity of the vvIBDV HuB-1 strain in chickens. However, the replication of the attenuated IBDV Gt strain was reduced in chicken embryo fibroblast cells, whilst it was enhanced in the bursa by substituting NEG with TEG or TDN. The exchange of the three amino acids was also found to be capable of affecting the polymerase activity of VP1. The important role of segment B in the pathogenicity of IBDV was confirmed in this study. These results also provided new insights into the mechanism of the virulence of vvIBDVs and may offer new targets for their attenuation to develop potential vaccines using reverse genetics.

scholarly journals Immunogenicity and Efficacy Evaluation of Vero Cell-Adapted Infectious Bursal Disease Virus LC-75 Vaccine Strain in Ethiopia 

2021 ◽  
Author(s):  
Wakjira Kebebe ◽  
Molalegne Bitew ◽  
Fufa Dawo ◽  
Bedaso Mammo ◽  
Hawa Mohammed ◽  
...  
Keyword(s):  
Vero Cell ◽  
Disease Virus ◽  
Vaccine Strain ◽  
Infectious Bursal Disease Virus ◽  
Chicken Embryo Fibroblast ◽  
Vero Cells ◽  
Infectious Bursal Disease ◽  
Efficacy Evaluation ◽  
Viral Pathogen ◽  
Bursal Disease

Abstract Background: Infectious bursal disease virus (IBDV) is an avian viral pathogen that causes infectious bursal disease (IBD) of chickens. The disease is endemic in Ethiopia since 2002 and vaccination is the major means of disease prevention and control. IBD vaccine is produced in Ethiopia using primary chicken embryo fibroblast (CEF) cell; which is time-consuming, laborious, and uneconomical. The present study was carried out to develop cell-based IBDV LC-75 vaccine using Vero cells, and to evaluate the immunogenicity and protection level.Results: Identity of the vaccine seed was confirmed using gene-specific primers using reverse transcription polymerase chain reaction. Confluent monolayer of Vero cells was infected with vaccine virus and serial passage continued till passage ten. Characteristic virus induced cytopathic effect was observed starting from passage 2 on the third day post-infection. The infectious titer of adapted virus showed a linear increment along the passage level. Virus induced specific antibody was determined using indirect ELISA after vaccination of 14 days old chicks through ocular route. Accordingly, the antibody titer measured from Vero cells vaccinated chicks revealed similar level with the currently available CEF cell-based vaccine. Chicks vaccinated with Vero cell adapted virus showed complete protection against very virulent IBDV, while unvaccinated group had 60% morbidity and 25% mortality.Conclusions: The IBDV vaccine strain well adapted on Vero cells and found to be immunogenic induces antibodies development and successfully protects chicks against challenging with the circulating field IBDV isolate. Hence, it is recommended to produce IBD vaccine using Vero cell culture with enough quantity to conquer the limitations using CEF cells and thus to vaccinate chicks to protect against IBDV infection.

scholarly journals Alteration of amino acids in VP2 of very virulent infectious bursal disease virus results in tissue culture adaptation and attenuation in chickens

2002 ◽  
Vol 83 (1) ◽  
pp. 121-129 ◽  
Author(s):  
A. A. W. M. van Loon ◽  
N. de Haas ◽  
I. Zeyda ◽  
E. Mundt
Keyword(s):  
Amino Acids ◽  
Tissue Culture ◽  
Amino Acid ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Site Directed Mutagenesis ◽  
Infectious Bursal Disease ◽  
Single Amino Acid ◽  
Culture Adaptation ◽  
Bursal Disease

Reverse genetics technology offers the possibility to study the influence of particular amino acids of infectious bursal disease virus (IBDV) on adaptation to tissue culture. Genomic segments A and B of the very virulent (vv) IBDV field strain UK661 were completely cloned and sequenced, and the strain was rescued from full-length cDNA copies of both segments (UK661rev). Using site-directed mutagenesis, alteration of a single amino acid in the segment A-encoded VP2 (A284T) resulted in a limited capacity of UK661 to replicate in tissue culture. Additional alteration of a second amino acid (Q253H) increased replication efficiency in tissue culture. The second mutant (UK661-Q253H-A284T) was used to infect chickens and results were compared with UK661 and UK661rev. Whereas UK661 and UK661rev induced 100% morbidity and 50–80% mortality, UK661-Q253H-A284T proved to be strikingly attenuated, producing neither morbidity nor mortality. Moreover, UK661-Q253H-A284T-infected animals were protected from challenge infection. Thus, alteration of two specific amino acids in the VP2 region of IBDV resulted in tissue culture adaptation and attenuation in chickens of vvIBDV. The data demonstrate that VP2 plays a decisive role in pathogenicity of IBDV.

scholarly journals Complete Genome Sequence of a Chicken Embryo Fibroblast-Adapted Attenuated Infectious Bursal Disease Virus Isolate from India

2016 ◽  
Vol 4 (3) ◽  
Author(s):  
T. M. A. Senthilkumar ◽  
C. V. Priyadharsini ◽  
P. Raja ◽  
K. Kumanan
Keyword(s):  
Disease Virus ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Infectious Bursal Disease Virus ◽  
Chicken Embryo Fibroblast ◽  
Infectious Bursal Disease ◽  
Avian Pathogen ◽  
Bursal Disease ◽  
Commercial Broiler

Infectious bursal disease virus is an avian pathogen that causes huge morbidity and mortality in the poultry sector all over the world. Here, we report the full-length genome sequence of an Indian strain, MB11/ABT/MVC/2016, isolated from a commercial broiler flock. This is a first report of a complete genome sequence of infectious bursal disease virus from India.

scholarly journals Molecular and Structural Bases for the Antigenicity of VP2 of Infectious Bursal Disease Virus

2007 ◽  
Vol 81 (23) ◽  
pp. 12827-12835 ◽  
Author(s):  
Tobias Letzel ◽  
Fasseli Coulibaly ◽  
Felix A. Rey ◽  
Bernard Delmas ◽  
Erik Jagt ◽  
...  
Keyword(s):  
Amino Acids ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Reverse Genetics ◽  
The United States ◽  
Antigenic Drift ◽  
Infectious Bursal Disease ◽  
Antigenic Determinants ◽  
Vp2 Gene ◽  
Bursal Disease

ABSTRACT Infectious bursal disease virus (IBDV), a member of the family Birnaviridae, is responsible for a highly contagious and economically important disease causing immunosuppression in chickens. IBDV variants isolated in the United States exhibit antigenic drift affecting neutralizing epitopes in the capsid protein VP2. To understand antigenic determinants of the virus, we have used a reverse-genetics approach to introduce selected amino acid changes—individually or in combination—into the VP2 gene of the classical IBDV strain D78. We thus generated a total of 42 mutants with changes in 8 amino acids selected by sequence comparison and their locations on loops PBC and PHI at the tip of the VP2 spikes, as shown by the crystal structure of the virion. The antibody reactivities of the mutants generated were assessed using a panel of five monoclonal antibodies (MAbs). Our results show that a few amino acids of the projecting domain of VP2 control the reactivity pattern. Indeed, the binding of four out of the five MAbs analyzed here is affected by mutations in these loops. Furthermore, their importance is highlighted by the fact that some of the engineered mutants display identical reactivity patterns but have different growth phenotypes. Finally, this analysis shows that a new field strain isolated from a chicken flock in Belgium (Bel-IBDV) represents an IBDV variant with a hitherto unobserved antigenic profile, involving one change (P222S) in the PBC loop. Overall, our data provide important new insights for devising efficient vaccines that protect against circulating IBDV strains.

scholarly journals Identification and Molecular Characterization of the RNA Polymerase-Binding Motif of Infectious Bursal Disease Virus Inner Capsid Protein VP3

2003 ◽  
Vol 77 (4) ◽  
pp. 2459-2468 ◽  
Author(s):  
Antonio Maraver ◽  
Roberto Clemente ◽  
Jose Francisco Rodríguez ◽  
Eleuterio Lombardo
Keyword(s):  
Rna Polymerase ◽  
Capsid Protein ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Critical Role ◽  
Rnase A ◽  
Infectious Bursal Disease ◽  
Binding Motif ◽  
Bursal Disease

ABSTRACT Infectious bursal disease virus (IBDV), a member of the Birnaviridae family, is the causative agent of one of the most important infectious poultry diseases. Major aspects of the molecular biology of IBDV, such as assembly and replication, are as yet poorly understood. We have previously shown that encapsidation of the putative virus-encoded RNA-dependent RNA polymerase VP1 is mediated by its interaction with the inner capsid protein VP3. Here, we report the characterization of the VP1-VP3 interaction. RNase A treatment of VP1- and VP3-containing extracts does not affect the formation of VP1-VP3 complexes, indicating that formation of the complex requires the establishment of protein-protein interactions. The use of a set of VP3 deletion mutants allowed the mapping of the VP1 binding motif of VP3 within a highly charged 16-amino-acid stretch on the C terminus of VP3. This region of VP3 is sufficient to confer VP1 binding activity when fused to an unrelated protein. Furthermore, a peptide corresponding to the VP1 binding region of VP3 specifically inhibits the formation of VP1-VP3 complexes. The presence of Trojan peptides containing the VP1 binding motif in IBDV-infected cells specifically reduces infective virus production, thus showing that formation of VP1-VP3 complexes plays a critical role in IBDV replication.

scholarly journals Molecular Characterization and Demographic Study on Infectious Bursal Disease Virus in Faisalabad District

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0254605
Author(s):  
Sanaullah Sajid ◽  
Sajjad ur Rahman ◽  
Mashkoor Mohsin Gilani ◽  
Zia ud Din Sindhu ◽  
Manel Ben Ali ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Nucleotide Sequences ◽  
Bursa Of Fabricius ◽  
Infectious Bursal Disease ◽  
Economic Losses ◽  
Effective Prevention ◽  
Molecular Features ◽  
Bursal Disease

The re-emergence of virulent strains of the Infectious Bursal Disease Virus (IBDV) leads to significant economic losses of poultry industry in Pakistan during last few years. This disease causes the infection of bursa, which leads to major immune losses. A total number of 30 samples from five IBD outbreaks during the period of 2019–20 were collected from different areas of Faisalabad district, Pakistan and assayed by targeting the IBD virus VP2 region through RT-PCR. Among all the outbreaks, almost 80% of poultry birds were found positive for the IBDV. The bursa tissues were collected from the infected birds and histopathological examination of samples revealed severe lymphocytic depletion, infiltration of inflammatory cells, and necrosis of the bursa of Fabricius (BF). Positive samples were subjected to re-isolation and molecular characterization of IBDV. The Pakistan IBDV genes were subjected to DNA sequencing to determine the virus nucleotide sequences. The sequences of 100 Serotype-I IBDVs showing nearest homology were compared and identified with the study sequence. The construction of the phylogenetic tree for nucleotide sequences was accomplished by the neighbor-joining method in MEGA-6 with reference strains. The VP2 segment reassortment of IBDVs carrying segment A were identified as one important type of circulating strains in Pakistan. The findings indicated the molecular features of the Pakistan IBDV strains playing a role in the evolution of new strains of the virus, which will contribute to the vaccine selection and effective prevention of the disease.

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