- Generation and Characterization of Recombinant Influenza A(H1N1) Viruses Resistant to Neuraminidase Inhibitors
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WooYoung Choi, Jin-Young Shin, Hwan-Eui Jeong, Mi-Jin Jeong, Su-Jin Kim, Joo-Yeon Lee, Chun Kang
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Osong Public Health Res Perspect. 2013;4(6):323-328. Published online December 31, 2013
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DOI: https://doi.org/10.1016/j.phrp.2013.10.005
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 Abstract
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- Objectives
To examine the effect of neuraminidase (NA) mutations on the NA inhibitor (NAI) resistance phenotype, the recombinant influenza A/Chungbuk/4448/2008(H1N1) virus isolated in South Korea during the 2008–2009 season was generated by reverse genetics.
Methods
Site-directed mutagenesis was introduced on the NA gene of A/Chungbuk/4448/2008(H1N1) virus, and a total of 23 single, double, and triple mutants were generated. Resistance phenotype of these recombinant viruses was determined by NA-inhibition (NAI) assays based on a fluorometric method using two NAIs (oseltamivir and zanamivir).
Results
NA-inhibition assays showed that all the single and double mutants containing the Y275 except the single Y275-E119V mutant conferred important levels of resistance to oseltamivir, whereas all the single, double, and triple mutants containing the E119V mutation were associated with the resistance to zanamivir.
Conclusion
Considering the effect of mutations in NA gene on the resistance to NAIs, it is important to monitor the possible emergence and dissemination of multidrug-resistant variants in the human population due to amino acid changes at NA gene as well as to develop novel NAIs.
- Pathogenesis and Chronologic Localization of the Human Influenza A (H1N1) Virus in Cotton Rats
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Donghyok Kwon, Kyeongcheol Shin, Jin-Young Shin, Joo-Yeon Lee, Yooncheol Ha, Nam-Joo Lee, Hee-Bok Oh, Chanhee Chae, Chun Kang
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Osong Public Health Res Perspect. 2011;2(1):15-22. Published online June 30, 2011
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DOI: https://doi.org/10.1016/j.phrp.2011.04.005
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1,683
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Abstract
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- Objectives
We aimed to evaluate the pathogenesis and chronologic localization of human influenza A (H1N1) virus in experimentally infected cotton rats.
Methods
The animals were intranasally inoculated with 107 plaque-forming units of A/Solomon Islands/3/2006 (H1N1) influenza virus and evaluated for pathogenicity for a period of 28 days. Virus replication kinetics and pathological properties were assessed chronologically. Acute antiviral responses were evaluated by mean of real-time polymerase chain reaction.
Results
Cotton rats infected with A/Solomon Islands/3/2006 virus lost weight until 6 days post-inoculation (DPI) and showed decreased activity until 3 DPI. At necropsy, focal areas of redness and consolidation of lungs were evident at 1, 2, and 3 DPI. Lung histopathology showed moderate to severe interstitial pneumonia, alveolitis and bronchiolitis. Influenza A specific viral protein was detected in bronchiolar epithelial cells, alveolar septa and pneumocytes. Influenza viruses were recovered from the lungs during the early period of infection and the titer peaked at 1 DPI. Viral proteins were detected from 4 hours to 6 hours DPI. These trends correlate with the up-regulation of mRNA expression of the IFN-α, Mx1, and Mx2 genes that play critical roles in the anti-influenza response at the early stage of infection.
Conclusion
Our results provide evidence that supports the use of cotton rats for the study of influenza virus pathogenesis and the immune response.
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