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Genetic divergence of influenza A NS1 gene in pandemic 2009 H1N1 isolates with respect to H1N1 and H3N2 isolates from previous seasonal epidemics.
Virol J. 2010 Sep 01; 7:209.VJ

Abstract

BACKGROUND

The Influenza A pandemic sustained by a new H1N1 variant (H1N1v) started in Mexico and the USA at the end of April 2009 spreading worldwide in a few weeks. In this study we investigate the variability of the NS1 gene of the pandemic H1N1v strain with respect to previous seasonal strains circulating in humans and the potential selection of virus variants through isolation in cell culture.

METHODS

During the period April 27th 2009-Jan 15th 2010, 1633 potential 2009 H1N1v cases have been screened at our center using the CDC detection and typing realtime RT-PCR assays. Virus isolation on MDCK cells was systematically performed in 1/10 positive cases. A subset of 51 H1N1v strains isolated in the period May-September 2009 was selected for NS1 gene sequencing. In addition, 15 H1N1 and 47 H3N2 virus isolates from three previous seasonal epidemics (2006-2009) were analyzed in parallel.

RESULTS

A low variability in the NS1 amino acid (aa) sequence among H1N1v isolates was shown (aa identity 99.5%). A slightly higher NS1 variability was observed among H1N1 and H3N2 strains from previous epidemics (aa identity 98.6% and 98.9%, respectively). The H1N1v strains were closely related (aa identity 92.1%) to swine reference strain (A/swine/Oklahoma/042169/2008). In contrast, substantial divergence (aa identity 83.4%) with respect to human reference strain A/Brevig Mission/1/1918 and previous epidemic strains H1N1 and H3N2 (aa identity 78.9% and 77.6%, respectively) was shown. Specific sequence signatures of uncertain significance in the new virus variant were a C-terminus deletion and a T215P substitution.

CONCLUSIONS

The H1N1v NS1 gene was more conserved than that of previous epidemic strains. In addition, a closer genetic identity of H1N1v with the swine than the human reference strains was shown. Hot-spots were shown in the H1N1v NS1 aa sequence whose biologic relevance remains to be investigated.

Authors+Show Affiliations

Molecular Virology Unit, Virology and Microbiology Dept, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

20809948

Citation

Campanini, Giulia, et al. "Genetic Divergence of Influenza a NS1 Gene in Pandemic 2009 H1N1 Isolates With Respect to H1N1 and H3N2 Isolates From Previous Seasonal Epidemics." Virology Journal, vol. 7, 2010, p. 209.
Campanini G, Piralla A, Paolucci S, et al. Genetic divergence of influenza A NS1 gene in pandemic 2009 H1N1 isolates with respect to H1N1 and H3N2 isolates from previous seasonal epidemics. Virol J. 2010;7:209.
Campanini, G., Piralla, A., Paolucci, S., Rovida, F., Percivalle, E., Maga, G., & Baldanti, F. (2010). Genetic divergence of influenza A NS1 gene in pandemic 2009 H1N1 isolates with respect to H1N1 and H3N2 isolates from previous seasonal epidemics. Virology Journal, 7, 209. https://doi.org/10.1186/1743-422X-7-209
Campanini G, et al. Genetic Divergence of Influenza a NS1 Gene in Pandemic 2009 H1N1 Isolates With Respect to H1N1 and H3N2 Isolates From Previous Seasonal Epidemics. Virol J. 2010 Sep 1;7:209. PubMed PMID: 20809948.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Genetic divergence of influenza A NS1 gene in pandemic 2009 H1N1 isolates with respect to H1N1 and H3N2 isolates from previous seasonal epidemics. AU - Campanini,Giulia, AU - Piralla,Antonio, AU - Paolucci,Stefania, AU - Rovida,Francesca, AU - Percivalle,Elena, AU - Maga,Giovanni, AU - Baldanti,Fausto, Y1 - 2010/09/01/ PY - 2010/07/26/received PY - 2010/09/01/accepted PY - 2010/9/3/entrez PY - 2010/9/3/pubmed PY - 2010/12/14/medline SP - 209 EP - 209 JF - Virology journal JO - Virol J VL - 7 N2 - BACKGROUND: The Influenza A pandemic sustained by a new H1N1 variant (H1N1v) started in Mexico and the USA at the end of April 2009 spreading worldwide in a few weeks. In this study we investigate the variability of the NS1 gene of the pandemic H1N1v strain with respect to previous seasonal strains circulating in humans and the potential selection of virus variants through isolation in cell culture. METHODS: During the period April 27th 2009-Jan 15th 2010, 1633 potential 2009 H1N1v cases have been screened at our center using the CDC detection and typing realtime RT-PCR assays. Virus isolation on MDCK cells was systematically performed in 1/10 positive cases. A subset of 51 H1N1v strains isolated in the period May-September 2009 was selected for NS1 gene sequencing. In addition, 15 H1N1 and 47 H3N2 virus isolates from three previous seasonal epidemics (2006-2009) were analyzed in parallel. RESULTS: A low variability in the NS1 amino acid (aa) sequence among H1N1v isolates was shown (aa identity 99.5%). A slightly higher NS1 variability was observed among H1N1 and H3N2 strains from previous epidemics (aa identity 98.6% and 98.9%, respectively). The H1N1v strains were closely related (aa identity 92.1%) to swine reference strain (A/swine/Oklahoma/042169/2008). In contrast, substantial divergence (aa identity 83.4%) with respect to human reference strain A/Brevig Mission/1/1918 and previous epidemic strains H1N1 and H3N2 (aa identity 78.9% and 77.6%, respectively) was shown. Specific sequence signatures of uncertain significance in the new virus variant were a C-terminus deletion and a T215P substitution. CONCLUSIONS: The H1N1v NS1 gene was more conserved than that of previous epidemic strains. In addition, a closer genetic identity of H1N1v with the swine than the human reference strains was shown. Hot-spots were shown in the H1N1v NS1 aa sequence whose biologic relevance remains to be investigated. SN - 1743-422X UR - https://www.unboundmedicine.com/medline/citation/20809948/Genetic_divergence_of_influenza_A_NS1_gene_in_pandemic_2009_H1N1_isolates_with_respect_to_H1N1_and_H3N2_isolates_from_previous_seasonal_epidemics_ L2 - https://virologyj.biomedcentral.com/articles/10.1186/1743-422X-7-209 DB - PRIME DP - Unbound Medicine ER -