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The PB2-E627K mutation attenuates viruses containing the 2009 H1N1 influenza pandemic polymerase.

Jagger BW, Memoli MJ, Sheng ZM, Qi L, Hrabal RJ, Allen GL, Dugan VG, Wang R, Digard P, Kash JC, Taubenberger JK - MBio (2010)

Bottom Line: The swine-origin H1N1 influenza A virus emerged in early 2009 and caused the first influenza pandemic in 41 years.The virus has spread efficiently to both the Northern and the Southern Hemispheres and has been associated with over 16,000 deaths.Given the virus's recent zoonotic origin, there is concern that the virus could acquire signature mutations associated with the enhanced pathogenicity of previous pandemic viruses or H5N1 viruses with pandemic potential.

View Article: PubMed Central - PubMed

Affiliation: Viral Pathogenesis and Evolution Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda,Maryland, USA.

ABSTRACT
The swine-origin H1N1 influenza A virus emerged in early 2009 and caused the first influenza pandemic in 41 years. The virus has spread efficiently to both the Northern and the Southern Hemispheres and has been associated with over 16,000 deaths. Given the virus's recent zoonotic origin, there is concern that the virus could acquire signature mutations associated with the enhanced pathogenicity of previous pandemic viruses or H5N1 viruses with pandemic potential. We tested the hypothesis that mutations in the polymerase PB2 gene at residues 627 and 701 would enhance virulence but found that influenza viruses containing these mutations in the context of the pandemic virus polymerase complex are attenuated in cell culture and mice.

No MeSH data available.


Related in: MedlinePlus

Pathology and immunohistochemistry of influenza virus-infected mouse lung tissue. Photomicrographs of hematoxylin-and-eosin-stained tissue sections and immunohistochemically stained sections for detection of influenza viral antigen from mice infected with different influenza virus constructs at day 5 postinfection (except for the VN1203RNP virus, which is shown at day 3 postinfection). Viral antigen is stained reddish brown on a hematoxylin-stained background. Arrows show examples of positive cells. (A, B) Sections from an animal infected with the S09RNP virus showing a focus of moderate alveolitis. Focal viral antigen is seen in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (C, D) Sections from an animal infected with the S09RNP-E627K virus showing necrotizing bronchiolitis with a transmural inflammatory cell infiltrate. Viral antigen staining was observed in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (E, F) Sections from an animal infected with the VN1203RNP virus at day 3 postinfection showing marked necrotizing bronchiolitis with a marked transmural inflammatory cell infiltrate. Prominent viral antigen staining was observed in bronchiolar epithelial cells (arrow) (original magnifications, ×100). Similar histopathological changes were observed at day 5, but only limited viral antigen staining was observed (data not shown). (G, H) Sections from an animal infected with the 1918RNP-K627E virus showing no pathological changes in the lung but some viral antigen staining in bronchiolar epithelial cells (arrow) in the absence of inflammation (original magnifications, ×100). (I, J) Sections from an animal infected with the CA09RNP-D701N virus showing no pathological changes in the lung and no viral antigen (original magnification, ×100).
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f5: Pathology and immunohistochemistry of influenza virus-infected mouse lung tissue. Photomicrographs of hematoxylin-and-eosin-stained tissue sections and immunohistochemically stained sections for detection of influenza viral antigen from mice infected with different influenza virus constructs at day 5 postinfection (except for the VN1203RNP virus, which is shown at day 3 postinfection). Viral antigen is stained reddish brown on a hematoxylin-stained background. Arrows show examples of positive cells. (A, B) Sections from an animal infected with the S09RNP virus showing a focus of moderate alveolitis. Focal viral antigen is seen in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (C, D) Sections from an animal infected with the S09RNP-E627K virus showing necrotizing bronchiolitis with a transmural inflammatory cell infiltrate. Viral antigen staining was observed in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (E, F) Sections from an animal infected with the VN1203RNP virus at day 3 postinfection showing marked necrotizing bronchiolitis with a marked transmural inflammatory cell infiltrate. Prominent viral antigen staining was observed in bronchiolar epithelial cells (arrow) (original magnifications, ×100). Similar histopathological changes were observed at day 5, but only limited viral antigen staining was observed (data not shown). (G, H) Sections from an animal infected with the 1918RNP-K627E virus showing no pathological changes in the lung but some viral antigen staining in bronchiolar epithelial cells (arrow) in the absence of inflammation (original magnifications, ×100). (I, J) Sections from an animal infected with the CA09RNP-D701N virus showing no pathological changes in the lung and no viral antigen (original magnification, ×100).

Mentions: To evaluate pathogenicity in vivo, the panel of viruses was intranasally inoculated into mice at a dose of 2 × 105 PFU. Daily weights of infected mice were obtained (Fig. 2) as an indicator of clinical disease, and lungs were collected to measure viral replication (Fig. 3) and observe histopathology (Fig. 4 and 5).


The PB2-E627K mutation attenuates viruses containing the 2009 H1N1 influenza pandemic polymerase.

Jagger BW, Memoli MJ, Sheng ZM, Qi L, Hrabal RJ, Allen GL, Dugan VG, Wang R, Digard P, Kash JC, Taubenberger JK - MBio (2010)

Pathology and immunohistochemistry of influenza virus-infected mouse lung tissue. Photomicrographs of hematoxylin-and-eosin-stained tissue sections and immunohistochemically stained sections for detection of influenza viral antigen from mice infected with different influenza virus constructs at day 5 postinfection (except for the VN1203RNP virus, which is shown at day 3 postinfection). Viral antigen is stained reddish brown on a hematoxylin-stained background. Arrows show examples of positive cells. (A, B) Sections from an animal infected with the S09RNP virus showing a focus of moderate alveolitis. Focal viral antigen is seen in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (C, D) Sections from an animal infected with the S09RNP-E627K virus showing necrotizing bronchiolitis with a transmural inflammatory cell infiltrate. Viral antigen staining was observed in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (E, F) Sections from an animal infected with the VN1203RNP virus at day 3 postinfection showing marked necrotizing bronchiolitis with a marked transmural inflammatory cell infiltrate. Prominent viral antigen staining was observed in bronchiolar epithelial cells (arrow) (original magnifications, ×100). Similar histopathological changes were observed at day 5, but only limited viral antigen staining was observed (data not shown). (G, H) Sections from an animal infected with the 1918RNP-K627E virus showing no pathological changes in the lung but some viral antigen staining in bronchiolar epithelial cells (arrow) in the absence of inflammation (original magnifications, ×100). (I, J) Sections from an animal infected with the CA09RNP-D701N virus showing no pathological changes in the lung and no viral antigen (original magnification, ×100).
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2912665&req=5

f5: Pathology and immunohistochemistry of influenza virus-infected mouse lung tissue. Photomicrographs of hematoxylin-and-eosin-stained tissue sections and immunohistochemically stained sections for detection of influenza viral antigen from mice infected with different influenza virus constructs at day 5 postinfection (except for the VN1203RNP virus, which is shown at day 3 postinfection). Viral antigen is stained reddish brown on a hematoxylin-stained background. Arrows show examples of positive cells. (A, B) Sections from an animal infected with the S09RNP virus showing a focus of moderate alveolitis. Focal viral antigen is seen in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (C, D) Sections from an animal infected with the S09RNP-E627K virus showing necrotizing bronchiolitis with a transmural inflammatory cell infiltrate. Viral antigen staining was observed in bronchiolar epithelial cells (arrow) and in alveolar macrophages (original magnifications, ×100). (E, F) Sections from an animal infected with the VN1203RNP virus at day 3 postinfection showing marked necrotizing bronchiolitis with a marked transmural inflammatory cell infiltrate. Prominent viral antigen staining was observed in bronchiolar epithelial cells (arrow) (original magnifications, ×100). Similar histopathological changes were observed at day 5, but only limited viral antigen staining was observed (data not shown). (G, H) Sections from an animal infected with the 1918RNP-K627E virus showing no pathological changes in the lung but some viral antigen staining in bronchiolar epithelial cells (arrow) in the absence of inflammation (original magnifications, ×100). (I, J) Sections from an animal infected with the CA09RNP-D701N virus showing no pathological changes in the lung and no viral antigen (original magnification, ×100).
Mentions: To evaluate pathogenicity in vivo, the panel of viruses was intranasally inoculated into mice at a dose of 2 × 105 PFU. Daily weights of infected mice were obtained (Fig. 2) as an indicator of clinical disease, and lungs were collected to measure viral replication (Fig. 3) and observe histopathology (Fig. 4 and 5).

Bottom Line: The swine-origin H1N1 influenza A virus emerged in early 2009 and caused the first influenza pandemic in 41 years.The virus has spread efficiently to both the Northern and the Southern Hemispheres and has been associated with over 16,000 deaths.Given the virus's recent zoonotic origin, there is concern that the virus could acquire signature mutations associated with the enhanced pathogenicity of previous pandemic viruses or H5N1 viruses with pandemic potential.

View Article: PubMed Central - PubMed

Affiliation: Viral Pathogenesis and Evolution Section, Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda,Maryland, USA.

ABSTRACT
The swine-origin H1N1 influenza A virus emerged in early 2009 and caused the first influenza pandemic in 41 years. The virus has spread efficiently to both the Northern and the Southern Hemispheres and has been associated with over 16,000 deaths. Given the virus's recent zoonotic origin, there is concern that the virus could acquire signature mutations associated with the enhanced pathogenicity of previous pandemic viruses or H5N1 viruses with pandemic potential. We tested the hypothesis that mutations in the polymerase PB2 gene at residues 627 and 701 would enhance virulence but found that influenza viruses containing these mutations in the context of the pandemic virus polymerase complex are attenuated in cell culture and mice.

No MeSH data available.


Related in: MedlinePlus