Increased Pathogenicity of a Reassortant 2009 Pandemic H1N1 Influenza Virus Containing an H5N1 Hemagglutinin

Cline, Troy; Karlsson, Erik A.; Freiden, Pamela; Seufzer, Bradley J.; Rehg, Jerold E.; Webby, Richard J.; Schultz‐Cherry, Stacey

doi:10.1128/jvi.05582-11

Cited by 45 publications

(52 citation statements)

References 36 publications

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“…The primer sequences are presented in Table 2. sortant CA/09 viruses expressing individual HK/483 viral genes were generated (30). The reassortant viruses all replicated to similar levels in MDCK cells (30).…”

Section: Resultsmentioning

confidence: 99%

“…Unbound virus was removed, and the cells were washed in PBS and maintained in RPMI 1640 medium containing 0.075% bovine serum albumin (BSA) in the presence (non-H5 viruses and low-pathogenicity H5 viruses) or absence (HPAI H5 viruses) of 1 g of TPCK (tolylsulfonyl phenylalanyl chloromethyl ketone)-treated trypsin (Pierce, Rockford, IL)/ml. Cell culture medium was removed at the indicated times and stored at Ϫ80°C for the determination of virus titers by TCID 50 analysis on MDCK cells as described previously (30). All TCID 50 titers are normalized to background levels of residual virus remaining in the culture wells after the inoculum was washed off.…”

Section: Ethicsmentioning

confidence: 99%

“…The limit of detection for the TCID 50 assay is 100 TCID 50 /ml. All in vitro experiments were performed with at least two different preparations of the reassortant virus (30).…”

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confidence: 99%

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The Hemagglutinin Protein of Highly Pathogenic H5N1 Influenza Viruses Overcomes an Early Block in the Replication Cycle To Promote Productive Replication in Macrophages

Cline

Karlsson

Seufzer

et al. 2013

J Virol

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Macrophages are known to be one of the first lines of defense against influenza virus infection. However, they may also contribute to severe disease caused by the highly pathogenic avian (HPAI) H5N1 influenza viruses. One reason for this may be the ability of certain influenza virus strains to productively replicate in macrophages. However, studies investigating the productive replication of influenza viruses in macrophages have been contradictory, and the results may depend on both the type of macrophages used and the specific viral strain. In this work, we investigated the ability of H1 to H16 viruses to productively replicate in primary murine alveolar macrophages and RAW264.7 macrophages. We show that only a subset of HPAI H5N1 viruses, those that cause high morbidity and mortality in mammals, can productively replicate in macrophages, as measured by the release of newly synthesized virus particles into the cell supernatant. Mechanistically, we found that these H5 strains can overcome a block early in the viral life cycle leading to efficient nuclear entry, viral transcription, translation, and ultimately replication. Studies with reassortant viruses demonstrated that expression of the hemagglutinin gene from an H5N1 virus rescued replication of H1N1 influenza virus in macrophages. This study is the first to characterize H5N1 influenza viruses as the only subtype of influenza virus capable of productive replication in macrophages and establishes the viral gene that is required for this characteristic. The ability to productively replicate in macrophages is unique to H5N1 influenza viruses and may contribute to their increased pathogenesis.

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Section: Resultsmentioning

confidence: 99%

Section: Ethicsmentioning

confidence: 99%

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The Hemagglutinin Protein of Highly Pathogenic H5N1 Influenza Viruses Overcomes an Early Block in the Replication Cycle To Promote Productive Replication in Macrophages

Cline

Karlsson

Seufzer

et al. 2013

J Virol

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“…When the replicative capacity of a panel of eight H5N1 viruses was tested in RAW264.7 cells, only those associated with high virulence in mammals were capable of productive replication, demonstrating a correlation between replication in macrophages and disease severity [39]. Further, a reassortant CA/09 virus expressing the HA protein from a HPAI H5 virus was capable of productive replication in macrophages and was associated with higher morbidity and mortality in mice relative to the WT CA/09 virus, which does not replicate in macrophages [51]. The increased disease severity was not linked directly to the ability of the virus to replicate in macrophages in this study, but it is intriguing to speculate that productive replication of H5N1 viruses in macrophages may alter antiviral macrophage functions in ways that lead to enhanced disease severity.…”

Section: Impact Of Productive Replication In Macrophages On Iav Pathomentioning

confidence: 99%

Influenza virus replication in macrophages: balancing protection and pathogenesis

Cline

Beck

Bianchini

2017

Journal of General Virology

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Macrophages are essential for protection against influenza A virus infection, but are also implicated in the morbidity and mortality associated with severe influenza disease, particularly during infection with highly pathogenic avian influenza (HPAI) H5N1 virus. While influenza virus infection of macrophages was once thought to be abortive, it is now clear that certain virus strains can replicate productively in macrophages. This may have important consequences for the antiviral functions of macrophages, the course of disease and the outcome of infection for the host. In this article, we review findings related to influenza virus replication in macrophages and the impact of productive replication on macrophage antiviral functions. A clear understanding of the interactions between influenza viruses and macrophages may lead to new antiviral therapies to relieve the burden of severe disease associated with influenza viruses.

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“…Reverse genetics-derived reassortant viruses (RGd-RV) that possess the H5N1 (H5) HA in an otherwise H3N2 genetic background show high replicative capacities in MDCK cells (10). Similarly, RGd-RV with the HA gene from H5N1 virus in the H1N1pdm2009 genetic background replicated efficiently in primary human respiratory epithelial cells and caused 100% mortality in mice (19). However, phylogenetic analyses of natural or experimental reassortant viruses have shown that the HA segment from avian, swine, or equine viruses was never incorporated alone in the genetic background of a human virus (13,14,20): The HA segment is packaged with additional groups of gene segments depending on the viral subtypes involved in the coinfection process (13,14).The inability to obtain a virus containing a nonhuman HA gene in an otherwise human genetic background, in contrast with the ability to produce "7+1" RGd-RV with a high yield of replication, suggests that the reassortment process might be restricted by suboptimal compatibility between the vRNA-packaging signals (10).…”

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confidence: 99%

Critical role of segment-specific packaging signals in genetic reassortment of influenza A viruses

Essere

Yver

Gavazzi

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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The fragmented nature of the influenza A genome allows the exchange of gene segments when two or more influenza viruses infect the same cell, but little is known about the rules underlying this process. Here, we studied genetic reassortment between the A/Moscow/10/99 (H3N2, MO) virus originally isolated from human and the avian A/Finch/England/2051/91 (H5N2, EN) virus and found that this process is strongly biased. Importantly, the avian HA segment never entered the MO genetic background alone but always was accompanied by the avian PA and M fragments. Introduction of the 5′ and 3′ packaging sequences of HA MO into an otherwise HA EN backbone allowed efficient incorporation of the chimerical viral RNA (vRNA) into the MO genetic background. Furthermore, forcing the incorporation of the avian M segment or introducing five silent mutations into the human M segment was sufficient to drive coincorporation of the avian HA segment into the MO genetic background. These silent mutations also strongly affected the genotype of reassortant viruses. Taken together, our results indicate that packaging signals are crucial for genetic reassortment and that suboptimal compatibility between the vRNA packaging signals, which are detected only when vRNAs compete for packaging, limit this process.hemagglutinin | RNA packaging

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Increased Pathogenicity of a Reassortant 2009 Pandemic H1N1 Influenza Virus Containing an H5N1 Hemagglutinin

Cited by 45 publications

References 36 publications

The Hemagglutinin Protein of Highly Pathogenic H5N1 Influenza Viruses Overcomes an Early Block in the Replication Cycle To Promote Productive Replication in Macrophages

The Hemagglutinin Protein of Highly Pathogenic H5N1 Influenza Viruses Overcomes an Early Block in the Replication Cycle To Promote Productive Replication in Macrophages

Influenza virus replication in macrophages: balancing protection and pathogenesis

Critical role of segment-specific packaging signals in genetic reassortment of influenza A viruses

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