scholarly journals VP5 and the N terminus of VP2 are not responsible for the different pathotype of serotype I and II infectious bursal disease virus

2001 ◽  
Vol 82 (1) ◽  
pp. 159-169 ◽  
Author(s):  
Anja Schröder ◽  
Adriaan A. W. M. van Loon ◽  
Danny Goovaerts ◽  
Jens Peter Teifke ◽  
Egbert Mundt
Keyword(s):  
B Lymphocytes ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Reverse Genetics ◽  
Bursa Of Fabricius ◽  
Infectious Bursal Disease ◽  
Bursal Disease ◽  
Chimeric Viruses

Two serotypes have been identified in infectious bursal disease virus (IBDV), a member of the family Birnaviridae. A reverse genetics system was used for generation of chimeras in genome segment A of the two serotypes, in which the complete viral VP5 gene and 3′ noncoding region (NCR), or parts thereof, were exchanged. The engineered viruses were characterized in vitro and in vivo in comparison to serotype I and II IBDV. Our results show that IBDV chimeras exhibit a different phenotype in cell culture compared to the wild-type viruses. In in vitro-cultivated bursal-derived cells, chimeric viruses infected B lymphocytes, as does serotype I IBDV. Surprisingly, serotype II virus was also able to infect in vitro-cultivated bursal cells, but these were neither B lymphocytes nor macrophages. After infection of susceptible chickens all chimeras replicated in the bursa of Fabricius (BF), and three chimeric viruses caused mild depletion of bursal cells. In contrast, after infection of chickens with a chimeric IBDV containing exchanged VP5 as well as 3′-NCR, no depletion was detectable. The serotype II strain did not replicate in the BF nor did it cause depletion of bursal cells. Thus, the origin of VP5 does not explain the different pathotype of IBDV serotype I and II.

Generation of serotype 1/serotype 2 reassortant viruses of the infectious bursal disease virus and their investigation in vitro and in vivo

2004 ◽  
Vol 105 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Kati Zierenberg ◽  
Rüdiger Raue ◽  
Hermann Nieper ◽  
Md.Rafiqul Islam ◽  
Nicolas Eterradossi ◽  
...  
Keyword(s):  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Bursal Disease ◽  
Serotype 1 ◽  
Reassortant Viruses

Chimeras in noncoding regions between serotypes I and II of segment A of infectious bursal disease virus are viable and show pathogenic phenotype in chickens

Microbiology ◽  
2000 ◽  
Vol 81 (2) ◽  
pp. 533-540 ◽  
Author(s):  
Anja Schröder ◽  
Adriaan A. W. M. van Loon ◽  
Danny Goovaerts ◽  
Egbert Mundt
Keyword(s):  
Cell Culture ◽  
Disease Virus ◽  
Cdna Clone ◽  
Infectious Bursal Disease Virus ◽  
Reverse Genetics ◽  
Infectious Bursal Disease ◽  
Noncoding Regions ◽  
The Family ◽  
Bursal Disease ◽  
Chimeric Viruses

Two serotypes, I and II, have been identified for infectious bursal disease virus (IBDV), a member of the family Birnaviridae. Here, the generation by reverse genetics of IBDV chimeras in segment A of the bisegmented genome is reported. The 5- and 3′-noncoding regions (NCRs) of a serotype II strain were exchanged with the NCRs of a full-length cDNA clone of segment A of a serotype I strain. Isolated chimeric viruses were characterized in cell culture and susceptible chickens. The results show that IBDV chimeras in segment A were able to replicate in cell culture and that VP1 encoded by a serotype I segment B is functionally active with serotype I NCRs as well as with serotype II NCRs. Chimeric viruses infected susceptible chickens and caused mild depletion of bursal cells. Thus, the noncoding regions of segment A are not responsible for the different pathotypes of IBDV serotypes I and II.

scholarly journals Tissue culture infectivity of different strains of infectious bursal disease virus is determined by distinct amino acids in VP2

1999 ◽  
Vol 80 (8) ◽  
pp. 2067-2076 ◽  
Author(s):  
Egbert Mundt
Keyword(s):  
Amino Acids ◽  
Tissue Culture ◽  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Reverse Genetics ◽  
Site Directed Mutagenesis ◽  
Bursa Of Fabricius ◽  
Infectious Bursal Disease ◽  
Embryonic Cells ◽  
Bursal Disease

Two types of strains of serotype I of infectious bursal disease virus (IBDV) have been described, on the basis of their ability (IBDV-TC) or inability (IBDV-BU) to infect chicken embryonic cells in culture. However, both types infect B lymphocytes in the bursa of Fabricius of young chickens. To determine the molecular basis for tissue culture infectivity, virus recombinants with chimeric segments A were constructed from IBDV-TC and IBDV-BU by reverse genetics. The region responsible for the different phenotypes was located in VP2. Site-directed mutagenesis identified single amino acids that are responsible for the restriction in infectivity. However, the appropriate amino acid exchanges are strain-specific.

scholarly journals Apoptosis is induced by infectious bursal disease virus replication in productively infected cells as well as in antigen-negative cells in their vicinity

2001 ◽  
Vol 82 (5) ◽  
pp. 1107-1115 ◽  
Author(s):  
Annett Jungmann ◽  
Hermann Nieper ◽  
Hermann Müller
Keyword(s):  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Infectious Bursal Disease ◽  
Virus Infectivity ◽  
Double Labelling ◽  
Apoptotic Cells ◽  
Bursal Disease ◽  
Induction Of Apoptosis

The kinetics of infectious bursal disease virus (IBDV) replication and induction of apoptosis were investigated in vitro and in vivo. After infection of chicken embryo (CE) cells with IBDV strain Cu-1, the proportion of apoptotic cells increased from 5·8% at 4 h post-infection (p.i.) to 64·5% at 48 h p.i. The proportion of apoptotic cells correlated with IBDV replication. UV-inactivated IBDV particles did not induce apoptosis. Double labelling revealed that, early after infection, the majority of antigen-expressing cells were not apoptotic; double-labelled cells appeared more frequently at later times. Remarkably, apoptotic cells were frequently located in the vicinity of antigen-expressing cells. This indicated that an apoptosis-inducing factor(s) might be released by cells that replicate IBDV. Since interferon (IFN) production has been demonstrated after IBDV infection, IFN was considered to be one of several factors. However, supernatants of infected CE cells in which virus infectivity had been neutralized were not sufficient to induce apoptosis.Similar results were observed in the infected bursae of Fabricius: early after infection, most of the cells either showed virus antigens or were apoptotic. Again, double-labelled cells appeared more frequently late after infection. This suggests that indirect mechanisms might also be involved in the induction of apoptosis in vivo, contributing to the rapid depletion of cells in the IBDV-infected bursa.

scholarly journals Generation of a Mutant Infectious Bursal Disease Virus That Does Not Cause Bursal Lesions

1998 ◽  
Vol 72 (4) ◽  
pp. 2647-2654 ◽  
Author(s):  
Kun Yao ◽  
Mark A. Goodwin ◽  
Vikram N. Vakharia
Keyword(s):  
Disease Virus ◽  
Infectious Bursal Disease Virus ◽  
Clinical Signs ◽  
Mutant Virus ◽  
Infectious Bursal Disease ◽  
Nucleotide Sequence Analysis ◽  
Fluorescence Signal ◽  
Bursal Disease

ABSTRACT A reverse genetics system for birnavirus, based on synthetic transcripts of the infectious bursal disease virus (IBDV) genome, was recently developed (E. Mundt and V. N. Vakharia, Proc. Natl. Acad. Sci. USA 93:11131–11136, 1996). To study the function of the 17-kDa nonstructural (NS) protein in viral growth and pathogenesis, we constructed a cDNA clone of IBDV segment A in which the first and only initiation codon (ATG) of NS protein was mutated to a stop codon (TAG). Transfection of Vero cells with combined transcripts of either modified or unmodified segment A, and with segment B, generated viable IBDV progeny. When chicken embryo fibroblast cells infected with transfectant viruses were analyzed by immunofluorescence assays using NS-specific antiserum, the mutant virus did not yield a fluorescence signal, indicating a lack of NS protein expression. Furthermore, replication kinetics and cytotoxic effects of the mutant virus were compared with those of the parental attenuated vaccine strain of IBDV (D78) in vitro. The mutant virus grew to slightly lower titers than D78 virus and exhibited decreased cytotoxic and apoptotic effects in cell culture. To evaluate the characteristics of the recovered viruses in vivo, we inoculated 3-week-old chickens with D78 or mutant virus and analyzed their bursa for histopathological lesions. The recovered D78 virus caused microscopic lesions and atrophy of the bursa, while the mutant virus failed to induce any pathological lesions or clinical signs of disease. In both instances, the virus was recovered from the bursa, and the presence or absence of mutation in these viruses was confirmed by nucleotide sequence analysis of NS gene. Although the mutant virus exhibited a delay in replication in vivo, it induced levels of IBDV neutralizing antibodies that were similar to those of D78 virus. In addition, no reversion of mutation was detected in the mutant virus recovered from inoculated chickens. These results demonstrate that NS protein is dispensable for viral replication in vitro and in vivo and that it plays an important role in viral pathogenesis. Thus, generation of such NS protein-deficient virus will facilitate the study of immunosuppression and aid in the development of live-attenuated vaccines for IBDV.

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