Virulence-associated sequence duplication at the hemagglutinin cleavage site of avian influenza viruses

Perdue, Michael L.; Garcı́a, Maricarmen; Senne, Dennis A.; Fraire, M.

doi:10.1016/s0168-1702(97)01468-8

Cited by 186 publications

(163 citation statements)

References 15 publications

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“…As the majority of influenza vaccines are manufactured in embryonated chicken eggs, influenza A vaccine candidate viruses are often egg‐adapted and reassorted with high‐growth parents to optimise growth in eggs. To facilitate growth in eggs and to improve the safety profile of potentially pathogenic vaccine candidates, mutations such as removal of the polybasic region in the haemagglutinin (HA) of H5N1 viruses must be introduced to remove regions of the viral genome that increase pathogenicity 6 , 7 , 8 , 9 . The vaccine candidate strain is produced using reverse genetics, using the mutated HA and neuraminidase (NA) of the candidate strain with the backbone genes of the egg‐adapted high‐growth strain A/Puerto Rico/8/34 10 , 11 , 12 , 13 .…”

Section: Introductionmentioning

confidence: 99%

Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA

Verity

Camuglia

Agius

et al. 2011

Influenza Resp Viruses

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Please cite this paper as: Verity et al. (2011) Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA. Influenza and Other Respiratory Viruses DOI:10.1111/j.1750‐2659.2011.00273.x. Background Vaccination is considered the most effective means of reducing influenza burden. The emergence of H5N1 and pandemic spread of novel H1N1/2009 viruses reinforces the need to have strategies in place to rapidly develop seed viruses for vaccine manufacture. Methods Candidate pandemic vaccine strains consisting of the circulating strain haemagglutinin (HA) and neuraminidase (NA) in an A/PR/8/34 backbone were generated using alternative synthetic DNA approaches, including site‐directed mutagenesis of DNA encoding related virus strains, and rapid generation of virus using synthetic DNA cloned into plasmid vectors. Results Firstly, synthetic A/Bar Headed Goose/Qinghai/1A/2005 (H5N1) virus was generated from an A/Vietnam/1194/2004 template using site‐directed mutagenesis. Secondly, A/Whooper Swan/Mongolia/244/2005 (H5N1) and A/California/04/09 (H1N1) viruses were generated using synthetic DNA encoding the viral HA and NA genes. Replication and antigenicity of the synthetic viruses were comparable to that of the corresponding non‐synthetic viruses. Conclusions In the event of an influenza pandemic, the use of these approaches may significantly reduce the time required to generate and distribute the vaccine seed virus and vaccine manufacture. These approaches also offer the advantage of not needing to handle wild‐type virus, potentially diminishing biocontainment requirements.

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Section: Introductionmentioning

confidence: 99%

Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA

Verity

Camuglia

Agius

et al. 2011

Influenza Resp Viruses

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“…HPAIVs evolve from low-pathogenic precursors by acquisition of a polybasic HA cleavage site Garten & Klenk, 2008;Horimoto et al, 1995b;Kawaoka & Webster, 1985;Pasick et al, 2005;Perdue et al, 1997;Suarez et al, 2004). Whereas back-conversion of this polybasic cleavage site to the initial monobasic motif results in a drastic reduction in virulence , the contrary mutation by insertion of a polybasic stretch into the HA cleavage site of a LPAIV may or may not lead to a HPAIV (Bogs et al, 2010;Munster et al, 2010;Stech et al, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Remarkably, there are some H5 HPAIVs that have polybasic HA cleavage motifs with threonine at P2 Garten & Klenk, 2008;Horimoto et al, 1995a;Pasick et al, 2005;Perdue et al, 1996Perdue et al, , 1997Saito et al, 1994;Suarez et al, 2004;Wood et al, 1993). These examples indicate that threonine at P2 does not impair the virulence of HPAIVs.…”

Section: Discussionmentioning

confidence: 99%

“…HPAIVs are known to evolve from LPAIVs Garten & Klenk, 2008;Horimoto et al, 1995b;Kawaoka & Webster, 1985;Perdue et al, 1997;Rohm et al, 1995) by insertion mutations at the cleavage site region. Several highly pathogenic strains have acquired fragments from the 28S rRNA sequence (Khatchikian et al, 1989) or a gene segment derived from the same or a different virus strain (Morsy et al, 1994;Pasick et al, 2005;Suarez et al, 2004) leading to elongation of the cleavage site region.…”

Section: Introductionmentioning

confidence: 99%

“…Several highly pathogenic strains have acquired fragments from the 28S rRNA sequence (Khatchikian et al, 1989) or a gene segment derived from the same or a different virus strain (Morsy et al, 1994;Pasick et al, 2005;Suarez et al, 2004) leading to elongation of the cleavage site region. Polybasic HA cleavage sites may also be generated by polymerase slippage Perdue et al, 1997). However, whereas transformation of the polybasic cleavage site to a monobasic motif results in a drastic reduction in virulence , conversion of the monobasic HA cleavage site of LPAIVs to a polybasic motif may or may not lead to HPAIVs (Bogs et al, 2010;Munster et al, 2010;Stech et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Amino acids adjacent to the haemagglutinin cleavage site are relevant for virulence of avian influenza viruses of subtype H5

Gohrbandt

Veits

Hundt

et al. 2010

Journal of General Virology

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The prime virulence determinant of highly pathogenic avian influenza viruses (HPAIVs) is the polybasic haemagglutinin (HA) cleavage site. However, engineering of a polybasic cleavage site into an avian influenza virus of low pathogenicity does not result in transformation into an HPAIV, indicating the importance of other adaptations. Here, the influence of amino acids adjacent to the HA cleavage site on virulence was studied. Most HPAIVs of subtype H5 carry serine or threonine at position 346 (corresponding to position 323 according to H3 numbering), whereas almost all low-pathogenic H5 viruses have valine. Moreover, all H5 low-pathogenic strains carry threonine at position 351 (corresponding to position 328 according to H3 numbering), suggesting that acquisition of a polybasic cleavage site involves several steps. This study generated a virus mutant derived from HPAIV A/Swan/Germany/R65/06 H5N1 (R65) with a monobasic cleavage site, R65 mono -S-ER, and the following additional mutants: R65 mono -V-ER with serine changed to valine at position 346, and R65 mono -S-ETR and R65 mono -V-ETR with threonine inserted at position 351. Moreover, in the R65 HA, serine was replaced with valine at position 346 (R65-V). Infection of chickens with R65 mono -S-ETR or R65 mono -S-ER led to slight transient respiratory symptoms, whereas R65-infected animals died within 2 days. However, chickens infected with R65-V survived longer than R65-infected animals, indicating that serine 346 in R65 HA contributes to virulence. These data suggest that evolution of H5 HPAIVs from low-pathogenic precursors, besides acquisition of a polybasic cleavage site, involves adaptation of neighbouring regions.

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Avian Influenza Viruses

Perdue

2006

Encyclopedia of Life Sciences

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Avian influenza viruses comprise scores of antigenic subtypes within the genus Influenza A of the Orthomyxoviridae family. They are found most prominently in migratory waterfowl and shorebirds and are sporadically transmitted to other avian and mammalian species. The consequences of such transmissions can range from a subclinical infection to a highly infectious and lethal respiratory disease. Further, such transmissions may result in increased gene mutations or the transfer of avian virus genes into other circulating influenza gene pools or both.

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Virulence-associated sequence duplication at the hemagglutinin cleavage site of avian influenza viruses

Cited by 186 publications

References 15 publications

Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA

Rapid generation of pandemic influenza virus vaccine candidate strains using synthetic DNA

Amino acids adjacent to the haemagglutinin cleavage site are relevant for virulence of avian influenza viruses of subtype H5

Avian Influenza Viruses

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