VP5 and the N terminus of VP2 are not responsible for the different pathotype of serotype I and II infectious bursal disease virus.
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.
Schröder
Anja
A
Institute of Molecular Biology1 and Infectiology3, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, D-17498 Insel Riems, Germany.
van Loon
Adriaan A W M
AAWM
Intervet International BV, NL-5830 AA Boxmeer, The Netherlands2.
Goovaerts
Danny
D
Intervet International BV, NL-5830 AA Boxmeer, The Netherlands2.
Teifke
Jens Peter
JP
Institute of Molecular Biology1 and Infectiology3, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, D-17498 Insel Riems, Germany.
Mundt
Egbert
E
Institute of Molecular Biology1 and Infectiology3, Friedrich-Loeffler-Institutes, Federal Research Centre for Virus Diseases of Animals, D-17498 Insel Riems, Germany.
D020413:3' Untranslated Regions / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000821:virology; D018175:Birnaviridae Infections / Q000473:pathology / Q000821:virology*; D002060:Bursa of Fabricius / Q000378:metabolism / Q000821:virology; D002478:Cells, Cultured; D002645:Chickens; D002678:Chimera / Q000821:virology; D007243:Infectious bursal disease virus / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D014158:Transcription, Genetic; D015678:Viral Structural Proteins / Q000235:genetics*; D014779:Virus Replication
D020413:3' Untranslated Regions; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins