Characterization In Vitro and In Vivo of Pandemic (H1N1) 2009 Influenza Viruses Isolated from Patients

Abstract BackgroundCurrently, Eurasian avian-like H1N1 (EA H1N1) swine influenza viruses (SIVs) are widely prevalent in pigs in China, with sporadic human cases reported as well. As one of the key molecular makers detected in avian H5N1 and H 7N9 viruses and pandemic H1N1 2009 virus, contributions of T271A in PB2 protein to the EA H1N1 viruses are still unknown. In this study, we investigated the effects of residue 271 in PB2 protein on the viral properties of EA H1N1 viruses.MethodsInfectivity, replication, virulence and pathogenicity of the recombinant viruses containing A or T in position 271 in PB2 protein were studied in cells and mice.ResultsThe results showed that the substitution PB2-T271A increased the viral replication in mammalian and avian cell lines. In addition, the mutation enhanced the viral infectivity, virulence and pathogenicity in mice. The viral titers of lung tissue in the rgHuN271A virus were higher than that of the rgHuN271T at 1, 4, and 7 dpi. The MID50 of the rgHuN271A and rgHuN271T virus were 101.1 TCID50 and 101.9 TCID50, respectively. Besides, the substitution of PB2-T271A enhanced the viral polymerase activity in mammalian cells.ConclusionsThe pathogenicity and replication of EA H1N1 virus containing 271A in PB2 protein were higher than the EA H1N1 virus containing 271T in PB2 protein in vivo and in vitro. Therefore, the PB2-T271A mutation should be continually monitored in influenza viruses circulating in pigs and humans.

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In vitro and in vivo characterization of new swine-origin H1N1 influenza viruses

Nature ◽

10.1038/nature08260 ◽

2009 ◽

Vol 460 (7258) ◽

pp. 1021-1025 ◽

Cited By ~ 763

Author(s):

Yasushi Itoh ◽

Kyoko Shinya ◽

Maki Kiso ◽

Tokiko Watanabe ◽

Yoshihiro Sakoda ◽

...

Keyword(s):

H1n1 Influenza ◽

Influenza Viruses ◽

In Vivo Characterization

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Host-targeted nitazoxanide has a high barrier to resistance but does not reduce the emergence or proliferation of oseltamivir-resistant influenza viruses in vitro or in vivo when used in combination with oseltamivir

Antiviral Research ◽

10.1016/j.antiviral.2020.104851 ◽

2020 ◽

Vol 180 ◽

pp. 104851

Author(s):

Danielle Tilmanis ◽

Paulina Koszalka ◽

Ian G. Barr ◽

Jean-Francois Rossignol ◽

Edin Mifsud ◽

...

Keyword(s):

Influenza Viruses

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Influenza A Virus Inhibits RSV Infection via a Two-Wave Expression of IFIT Proteins

Viruses ◽

10.3390/v12101171 ◽

2020 ◽

Vol 12 (10) ◽

pp. 1171

Author(s):

Yaron Drori ◽

Jasmine Jacob-Hirsch ◽

Rakefet Pando ◽

Aharona Glatman-Freedman ◽

Nehemya Friedman ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Influenza Viruses ◽

Mass Spectrometry Analysis ◽

Influenza A Viruses ◽

Rsv Infection ◽

Syncytial Virus ◽

Mouse Lungs

Influenza viruses and respiratory syncytial virus (RSV) are respiratory viruses that primarily circulate worldwide during the autumn and winter seasons. Seasonal surveillance has shown that RSV infection generally precedes influenza. However, in the last four winter seasons (2016–2020) an overlap of the morbidity peaks of both viruses was observed in Israel, and was paralleled by significantly lower RSV infection rates. To investigate whether the influenza A virus inhibits RSV, human cervical carcinoma (HEp2) cells or mice were co-infected with influenza A and RSV. Influenza A inhibited RSV growth, both in vitro and in vivo. Mass spectrometry analysis of mouse lungs infected with influenza A identified a two-wave pattern of protein expression upregulation, which included members of the interferon-induced protein with the tetratricopeptide (IFITs) family. Interestingly, in the second wave, influenza A viruses were no longer detectable in mouse lungs. In addition, knockdown and overexpression of IFITs in HEp2 cells affected RSV multiplicity. In conclusion, influenza A infection inhibits RSV infectivity via upregulation of IFIT proteins in a two-wave modality. Understanding the immune system involvement in the interaction between influenza A and RSV viruses will contribute to the development of future treatment strategies against these viruses.

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Influenza B Virus NS1-Truncated Mutants: Live-Attenuated Vaccine Approach

Journal of Virology ◽

10.1128/jvi.01213-08 ◽

2008 ◽

Vol 82 (21) ◽

pp. 10580-10590 ◽

Cited By ~ 73

Author(s):

Rong Hai ◽

Luis Martínez-Sobrido ◽

Kathryn A. Fraser ◽

Juan Ayllon ◽

Adolfo García-Sastre ◽

...

Keyword(s):

Reverse Genetics ◽

Influenza Viruses ◽

Influenza B Virus ◽

Influenza B ◽

Type I ◽

Live Attenuated Vaccine ◽

Live Virus ◽

B Virus

ABSTRACT Type B influenza viruses can cause substantial morbidity and mortality in the population, and vaccination remains by far the best means of protection against infections with these viruses. Here, we report the construction of mutant influenza B viruses for potential use as improved live-virus vaccine candidates. Employing reverse genetics, we altered the NS1 gene, which encodes a type I interferon (IFN) antagonist. The resulting NS1 mutant viruses induced IFN and, as a consequence, were found to be attenuated in vitro and in vivo. The absence of pathogenicity of the NS1 mutants in both BALB/c and C57BL/6 PKR−/− mice was confirmed. We also provide evidence that influenza B virus NS1 mutants induce a self-adjuvanted immune response and confer effective protection against challenge with both homologous and heterologous B virus strains in mice.

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Seroconversion to Pandemic (H1N1) 2009 Virus and Cross-Reactive Immunity to Other Swine Influenza Viruses

Emerging Infectious Diseases ◽

10.3201/eid1710.110629 ◽

2011 ◽

Vol 17 (10) ◽

pp. 1897-1899 ◽

Cited By ~ 11

Author(s):

Ranawaka A.P.M. Perera ◽

Steven Riley ◽

Siu K. Ma ◽

Hua-Chen Zhu ◽

Yi Guan ◽

...

Keyword(s):

Swine Influenza ◽

Influenza Viruses ◽

Pandemic H1n1 ◽

Pandemic H1n1 2009

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N-linked glycosylation plays an important role in budding of NA protein and virulence of influenza viruses

Journal of Virology ◽

10.1128/jvi.02042-20 ◽

2020 ◽

Author(s):

Danqi Bao ◽

Ruixue Xue ◽

Min Zhang ◽

Chenyang Lu ◽

Tianxin Ma ◽

...

Keyword(s):

Influenza Virus ◽

Virus Replication ◽

Immune Escape ◽

H1n1 Influenza ◽

Influenza Viruses ◽

H1n1 Influenza Virus ◽

Protein Loss ◽

Knock Out

Neuraminidase (NA) has multiple functions in the life cycle of influenza virus, especially in the late stage of virus replication. Both of Hemagglutinin (HA) and NA are highly glycosylated proteins. N-linked glycosylation (NLG) of HA has been reported to contribute to immune escape and virulence of influenza viruses. However, the function of NLG of NA remains largely unclear. In this study, we found that NLG is critical for budding ability of NA. Tunicamycin treatment or NLG knock-out significantly inhibited the budding of NA. Further studies showed that the NLG knock-out caused attenuation of virus in vitro and in vivo. Notably the NLG at 219 position plays an important role in budding, replication, and virulence of H1N1 influenza virus. To explore the underlying mechanism, unfolded protein response (UPR) was determined in NLG knock-out NA overexpressed cells, which showed that the mutant NA was mainly located in ER, and the UPR markers BIP and p-eIF2α were upregulated, and XBP1 was downregulated. All the results indicated that NLG knock-out NA was stacked in ER and triggered UPR, which might shut down the budding process of NA. Overall, the study shed light on the function of NLG of NA in virus replication and budding. IMPORTANCE NA is a highly glycosylated protein. Nevertheless, how the NLG affects the function of NA protein remains largely unclear. In this study, we found that NLG plays important roles in budding and Neuraminidase activity of NA protein. Loss of NLG attenuated viral budding and replication. Especially the 219 NLG site mutation significantly attenuated the replication and virulence of H1N1 influenza virus in vitro and in vivo, which suggested that NLG of NA protein is a novel virulence marker for influenza viruses.

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Full-genome analysis of the pandemic (H1N1) 2009 influenza viruses isolated in Ukraine during 2009-2017 years

International Journal of Infectious Diseases ◽

10.1016/j.ijid.2018.11.040 ◽

2019 ◽

Vol 79 ◽

pp. 9

Author(s):

O. Smutko ◽

A. Fesenko ◽

L. Radchenko ◽

O. Onishchenko ◽

L. Leibenko ◽

...

Keyword(s):

Genome Analysis ◽

Influenza Viruses ◽

Pandemic H1n1 ◽

Full Genome ◽

Full Genome Analysis ◽

Pandemic H1n1 2009

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Genetically and Antigenically Divergent Influenza A(H9N2) Viruses Exhibit Differential Replication and Transmission Phenotypes in Mammalian Models

Journal of Virology ◽

10.1128/jvi.00451-20 ◽

2020 ◽

Vol 94 (17) ◽

Author(s):

Jessica A. Belser ◽

Xiangjie Sun ◽

Nicole Brock ◽

Claudia Pappas ◽

Joanna A. Pulit-Penaloza ◽

...

Keyword(s):

Influenza A ◽

Human Infection ◽

Influenza Viruses ◽

Human Populations ◽

Human Respiratory Tract ◽

Live Bird Markets ◽

Human Infections ◽

Live Bird

ABSTRACT Low-pathogenicity avian influenza A(H9N2) viruses, enzootic in poultry populations in Asia, are associated with fewer confirmed human infections but higher rates of seropositivity compared to A(H5) or A(H7) subtype viruses. Cocirculation of A(H5) and A(H7) viruses leads to the generation of reassortant viruses bearing A(H9N2) internal genes with markers of mammalian adaptation, warranting continued surveillance in both avian and human populations. Here, we describe active surveillance efforts in live poultry markets in Vietnam in 2018 and compare representative viruses to G1 and Y280 lineage viruses that have infected humans. Receptor binding properties, pH thresholds for HA activation, in vitro replication in human respiratory tract cells, and in vivo mammalian pathogenicity and transmissibility were investigated. While A(H9N2) viruses from both poultry and humans exhibited features associated with mammalian adaptation, one human isolate from 2018, A/Anhui-Lujiang/39/2018, exhibited increased capacity for replication and transmission, demonstrating the pandemic potential of A(H9N2) viruses. IMPORTANCE A(H9N2) influenza viruses are widespread in poultry in many parts of the world and for over 20 years have sporadically jumped species barriers to cause human infection. As these viruses continue to diversify genetically and antigenically, it is critical to closely monitor viruses responsible for human infections, to ascertain if A(H9N2) viruses are acquiring properties that make them better suited to infect and spread among humans. In this study, we describe an active poultry surveillance system established in Vietnam to identify the scope of influenza viruses present in live bird markets and the threat they pose to human health. Assessment of a recent A(H9N2) virus isolated from an individual in China in 2018 is also reported, and it was found to exhibit properties of adaptation to humans and, importantly, it shows similarities to strains isolated from the live bird markets of Vietnam.

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