IPNV with high and low virulence: host immune responses and viral mutations during infection
Infectious pancreatic necrosis virus (IPNV) is an aquatic member of the Birnaviridae family that causes widespread disease in salmonids. IPNV is represented by multiple strains with markedly different virulence. Comparison of isolates reveals hyper variable regions (HVR), which are presumably associ...
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BioMed Central
2011
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Online Access: | https://hdl.handle.net/10037/4017 https://doi.org/10.1186/1743-422X-8-396 |
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ftunivtroemsoe:oai:munin.uit.no:10037/4017 2023-05-15T15:33:07+02:00 IPNV with high and low virulence: host immune responses and viral mutations during infection Skjesol, Astrid SkjÆveland, ingrid Elnæs, Marianne Timmerhaus, Gerrit Frantz Fredriksen, Børge Nilsen Jørgensen, Sven Martin Krasnov, Aleksei Jørgensen, Jorunn B 2011 https://hdl.handle.net/10037/4017 https://doi.org/10.1186/1743-422X-8-396 eng eng BioMed Central Virology Journal (2011), 8:396 FRIDAID 858384 doi:10.1186/1743-422X-8-396 1743-422X https://hdl.handle.net/10037/4017 URN:NBN:no-uit_munin_3738 openAccess VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Fiskehelse: 923 Journal article Tidsskriftartikkel Peer reviewed 2011 ftunivtroemsoe https://doi.org/10.1186/1743-422X-8-396 2021-06-25T17:53:15Z Infectious pancreatic necrosis virus (IPNV) is an aquatic member of the Birnaviridae family that causes widespread disease in salmonids. IPNV is represented by multiple strains with markedly different virulence. Comparison of isolates reveals hyper variable regions (HVR), which are presumably associated with pathogenicity. However little is known about the rates and modes of sequence divergence and molecular mechanisms that determine virulence. Also how the host response may influence IPNV virulence is poorly described. In this study we compared two field isolates of IPNV (NFH-Ar and NFH-El). The sequence changes, replication and mortality were assessed following experimental challenge of Atlantic salmon. Gene expression analyses with qPCR and microarray were applied to examine the immune responses in head kidney. Significant differences in mortality were observed between the two isolates, and viral load in the pancreas at 13 days post infection (d p.i.) was more than 4 orders of magnitude greater for NFH-Ar in comparison with NFH-El. Sequence comparison of five viral genes from the IPNV isolates revealed different mutation rates and Ka/Ks ratios. A strong tendency towards non-synonymous mutations was found in the HRV of VP2 and in VP3. All mutations in VP5 produced precocious stop codons. Prior to the challenge, NFH-Ar and NFH-El possessed high and low virulence motifs in VP2, respectively. Nucleotide substitutions were noticed already during passage of viruses in CHSE-214 cells and their accumulation continued in the challenged fish. The sequence changes were notably directed towards low virulence. Co-ordinated activation of anti-viral genes with diverse functions (IFN-a1 and c, sensors - Rig-I, MDA-5, TLR8 and 9, signal transducers - Srk2, MyD88, effectors - Mx, galectin 9, galectin binding protein, antigen presentation - b2-microglobulin) was observed at 13 d p.i. (NFH-Ar) and 29 d p.i. (both isolates). Mortality and expression levels of the immune genes were directly related to the rate of viral replication, which was in turn associated with sequences of viral genes. Rapid changes in the viral genome that dramatically reduced virus proliferation might indicate a higher susceptibility to protective mechanism employed by the host. Disease outbreak and mortality depend on a delicate balance between host defence, regulation of signalling cascades and virus genomic properties. Article in Journal/Newspaper Atlantic salmon University of Tromsø: Munin Open Research Archive Virology Journal 8 1 396 |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Fiskehelse: 923 |
spellingShingle |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Fiskehelse: 923 Skjesol, Astrid SkjÆveland, ingrid Elnæs, Marianne Timmerhaus, Gerrit Frantz Fredriksen, Børge Nilsen Jørgensen, Sven Martin Krasnov, Aleksei Jørgensen, Jorunn B IPNV with high and low virulence: host immune responses and viral mutations during infection |
topic_facet |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Aquaculture: 922 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Akvakultur: 922 VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920::Fish health: 923 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920::Fiskehelse: 923 |
description |
Infectious pancreatic necrosis virus (IPNV) is an aquatic member of the Birnaviridae family that causes widespread disease in salmonids. IPNV is represented by multiple strains with markedly different virulence. Comparison of isolates reveals hyper variable regions (HVR), which are presumably associated with pathogenicity. However little is known about the rates and modes of sequence divergence and molecular mechanisms that determine virulence. Also how the host response may influence IPNV virulence is poorly described. In this study we compared two field isolates of IPNV (NFH-Ar and NFH-El). The sequence changes, replication and mortality were assessed following experimental challenge of Atlantic salmon. Gene expression analyses with qPCR and microarray were applied to examine the immune responses in head kidney. Significant differences in mortality were observed between the two isolates, and viral load in the pancreas at 13 days post infection (d p.i.) was more than 4 orders of magnitude greater for NFH-Ar in comparison with NFH-El. Sequence comparison of five viral genes from the IPNV isolates revealed different mutation rates and Ka/Ks ratios. A strong tendency towards non-synonymous mutations was found in the HRV of VP2 and in VP3. All mutations in VP5 produced precocious stop codons. Prior to the challenge, NFH-Ar and NFH-El possessed high and low virulence motifs in VP2, respectively. Nucleotide substitutions were noticed already during passage of viruses in CHSE-214 cells and their accumulation continued in the challenged fish. The sequence changes were notably directed towards low virulence. Co-ordinated activation of anti-viral genes with diverse functions (IFN-a1 and c, sensors - Rig-I, MDA-5, TLR8 and 9, signal transducers - Srk2, MyD88, effectors - Mx, galectin 9, galectin binding protein, antigen presentation - b2-microglobulin) was observed at 13 d p.i. (NFH-Ar) and 29 d p.i. (both isolates). Mortality and expression levels of the immune genes were directly related to the rate of viral replication, which was in turn associated with sequences of viral genes. Rapid changes in the viral genome that dramatically reduced virus proliferation might indicate a higher susceptibility to protective mechanism employed by the host. Disease outbreak and mortality depend on a delicate balance between host defence, regulation of signalling cascades and virus genomic properties. |
format |
Article in Journal/Newspaper |
author |
Skjesol, Astrid SkjÆveland, ingrid Elnæs, Marianne Timmerhaus, Gerrit Frantz Fredriksen, Børge Nilsen Jørgensen, Sven Martin Krasnov, Aleksei Jørgensen, Jorunn B |
author_facet |
Skjesol, Astrid SkjÆveland, ingrid Elnæs, Marianne Timmerhaus, Gerrit Frantz Fredriksen, Børge Nilsen Jørgensen, Sven Martin Krasnov, Aleksei Jørgensen, Jorunn B |
author_sort |
Skjesol, Astrid |
title |
IPNV with high and low virulence: host immune responses and viral mutations during infection |
title_short |
IPNV with high and low virulence: host immune responses and viral mutations during infection |
title_full |
IPNV with high and low virulence: host immune responses and viral mutations during infection |
title_fullStr |
IPNV with high and low virulence: host immune responses and viral mutations during infection |
title_full_unstemmed |
IPNV with high and low virulence: host immune responses and viral mutations during infection |
title_sort |
ipnv with high and low virulence: host immune responses and viral mutations during infection |
publisher |
BioMed Central |
publishDate |
2011 |
url |
https://hdl.handle.net/10037/4017 https://doi.org/10.1186/1743-422X-8-396 |
genre |
Atlantic salmon |
genre_facet |
Atlantic salmon |
op_relation |
Virology Journal (2011), 8:396 FRIDAID 858384 doi:10.1186/1743-422X-8-396 1743-422X https://hdl.handle.net/10037/4017 URN:NBN:no-uit_munin_3738 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.1186/1743-422X-8-396 |
container_title |
Virology Journal |
container_volume |
8 |
container_issue |
1 |
container_start_page |
396 |
_version_ |
1766363584279871488 |