scholarly journals Ostrich Involvement in the Selection of H5N1 Influenza Virus Possessing Mammalian-Type Amino Acids in the PB2 Protein

2009 ◽  
Vol 83 (24) ◽  
pp. 13015-13018 ◽  
Author(s):  
Kyoko Shinya ◽  
Akiko Makino ◽  
Makoto Ozawa ◽  
Jin Hyun Kim ◽  
Yuko Sakai-Tagawa ◽  
...  
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Mammalian Cells ◽  
Influenza A ◽  
Influenza Viruses ◽  
High Rate ◽  
Qinghai Lake ◽  
H5n1 Influenza

ABSTRACT Amino acids at positions 627 and 701 in the PB2 protein (PB2-627 and PB2-701, respectively) of avian influenza A viruses affect virus replication in some mammalian cells. Highly pathogenic H5N1 influenza viruses possessing mammalian-type PB2-627 were detected during the Qinghai Lake outbreak in 2005 and spread to Europe and Africa. Via a database search, we found a high rate of viral isolates from Ratitae, including ostrich, possessing mammalian-type PB2-627 or -701. Here, we report that H5N1 avian influenza viruses possessing mammalian-type amino acids in PB2-627 or -701 are selected during replication in ostrich cells in vitro and in vivo.

scholarly journals Pathogenesis and Transmission Assessments of Two H7N8 Influenza A Viruses Recently Isolated from Turkey Farms in Indiana Using Mouse and Ferret Models

2016 ◽  
Vol 90 (23) ◽  
pp. 10936-10944 ◽  
Author(s):  
Xiangjie Sun ◽  
Jessica A. Belser ◽  
Joanna A. Pulit-Penaloza ◽  
Hui Zeng ◽  
Amanda Lewis ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Influenza Viruses ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
Pathogenic Avian Influenza ◽  
Domestic Poultry ◽  
Commercial Turkey

ABSTRACTAvian influenza A H7 viruses have caused multiple outbreaks in domestic poultry throughout North America, resulting in occasional infections of humans in close contact with affected birds. In early 2016, the presence of H7N8 highly pathogenic avian influenza (HPAI) viruses and closely related H7N8 low-pathogenic avian influenza (LPAI) viruses was confirmed in commercial turkey farms in Indiana. These H7N8 viruses represent the first isolation of this subtype in domestic poultry in North America, and their virulence in mammalian hosts and the potential risk for human infection are largely unknown. In this study, we assessed the ability of H7N8 HPAI and LPAI viruses to replicatein vitroin human airway cells andin vivoin mouse and ferret models. Both H7N8 viruses replicated efficientlyin vitroandin vivo, but they exhibited substantial differences in disease severity in mammals. In mice, while the H7N8 LPAI virus largely remained avirulent, the H7N8 HPAI virus exhibited greater infectivity, virulence, and lethality. Both H7N8 viruses replicated similarly in ferrets, but only the H7N8 HPAI virus caused moderate weight loss, lethargy, and mortality. The H7N8 LPAI virus displayed limited transmissibility in ferrets placed in direct contact with an inoculated animal, while no transmission of H7N8 HPAI virus was detected. Our results indicate that the H7N8 avian influenza viruses from Indiana are able to replicate in mammals and cause severe disease but with limited transmission. The recent appearance of H7N8 viruses in domestic poultry highlights the need for continued influenza surveillance in wild birds and close monitoring of the potential risk to human health.IMPORTANCEH7 influenza viruses circulate in wild birds in the United States, but when the virus emerges in domestic poultry populations, the frequency of human exposure and the potential for human infections increases. An H7N8 highly pathogenic avian influenza (HPAI) virus and an H7N8 low-pathogenic avian influenza (LPAI) virus were recently isolated from commercial turkey farms in Indiana. To determine the risk that these influenza viruses pose to humans, we assessed their pathogenesis and transmissionin vitroand in mammalian models. We found that the H7N8 HPAI virus exhibited enhanced virulence, and although transmission was only observed with the H7N8 LPAI virus, the ability of this H7 virus to transmit in a mammalian host and quickly evolve to a more virulent strain is cause for concern. Our findings offer important insight into the potential for emerging H7 avian influenza viruses to acquire the ability to cause disease and transmit among mammals.

scholarly journals Antibodies directed towards neuraminidase N1 control disease in a mouse model of influenza

2017 ◽  
pp. JVI.01584-17 ◽  
Author(s):  
E.R. Job ◽  
M. Schotsaert ◽  
L.I. Ibañez ◽  
A. Smet ◽  
T. Ysenbaert ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Antiviral Activity ◽  
Influenza A ◽  
Conformational Epitope ◽  
Influenza Viruses ◽  
Lethal Challenge ◽  
H5n1 Influenza ◽  
Antigenic Properties

There is increasing evidence to suggest that antibodies directed towards influenza A virus (IAV) neuraminidase (NA) are an important correlate of protection against influenza in humans. Moreover, the potential of NA-specific antibodies to provide broader protection than conventional hemagglutinin (HA) antibodies has been recognized. Herein, we describe the isolation of two monoclonal antibodies, N1-7D3 and N1-C4, directed towards the N1 NA. N1-7D3 binds to a conserved linear epitope in the membrane distal, carboxy-terminal part of the NA and reacted with the NA of seasonal H1N1 isolates ranging from 1977 till 2007 the 2009 H1N1pdm virus as well as A/Vietnam/1194/04 (H5N1). However, N1-7D3 lacked NA inhibition (NI) activity and the ability to protect BALB/c mice against a lethal challenge with a range of H1N1 viruses. Conversely, N1-C4 bound to a conformational epitope that is conserved between two influenza subtypes, the 2009 H1N1pdm and H5N1 IAV and displayed potentin vitroantiviral activity mediating both NI and plaque size-reduction. Moreover, N1-C4 could provide heterosubtypic protection in BALB/c mice against a lethal challenge with 2009 H1N1pdm or H5N1 virus. Glutamic acid residue 311 in the NA was found to be critical for the NA binding and antiviral activity of monoclonal antibody N1-C4. Our data provide further evidence on cross-protective epitopes within the N1 subtype and highlight the potential of NA as an important target for vaccine and therapeutic approaches.ImportanceInfluenza remains a world-wide burden to public health. As such the development of new and novel vaccines and therapeutics against influenza virus is crucial. Human challenge studies have recently highlighted the importance of antibodies directed towards the viral neuraminidase (NA) as an important correlate of reduced influenza-associated disease severity. Furthermore, there is evidence that anti-NA antibodies can provide broader protection than antibodies towards the viral hemagglutinin. Here we describe the isolation and detailed characterization of two N1 NA-specific monoclonal antibodies. One of these monoclonal antibodies broadly binds N1 type NAs and the second one displays NAI, in vitro and in vivo anti-viral activity against 2009 H1N1pdm and H5N1 influenza viruses. These two new anti-NA antibodies contribute to our understanding of the antigenic properties and protective potential of the influenza NA antigen.

scholarly journals PA Mutations Inherited during Viral Evolution Act Cooperatively To Increase Replication of Contemporary H5N1 Influenza Virus with an Expanded Host Range

2020 ◽  
Vol 95 (1) ◽  
Author(s):  
Yasuha Arai ◽  
Norihito Kawashita ◽  
Emad Mohamed Elgendy ◽  
Madiha Salah Ibrahim ◽  
Tomo Daidoji ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Host Range ◽  
Human Cells ◽  
Influenza Viruses ◽  
Human Adaptation ◽  
Avian Influenza Viruses ◽  
H5n1 Influenza

ABSTRACT Adaptive mutations and/or reassortments in avian influenza virus polymerase subunits PA, PB1, and PB2 are one of the major factors enabling the virus to overcome the species barrier to infect humans. The majority of human adaptation polymerase mutations have been identified in PB2; fewer adaptation mutations have been characterized in PA and PB1. Clade 2.2.1 avian influenza viruses (H5N1) are unique to Egypt and generally carry the human adaptation PB2-E627K substitution during their dissemination in nature. In this study, we identified other human adaptation polymerase mutations by analyzing phylogeny-associated PA mutations that H5N1 clade 2.2.1 viruses have accumulated during their evolution in the field. This analysis identified several PA mutations that produced increased replication by contemporary clade 2.2.1.2 viruses in vitro in human cells and in vivo in mice compared to ancestral clade 2.2.1 viruses. The PA mutations acted cooperatively to increase viral polymerase activity and replication in both avian and human cells, with the effect being more prominent in human cells at 33°C than at 37°C. These results indicated that PA mutations have a role in establishing contemporary clade 2.2.1.2 virus infections in poultry and in adaptation to infect mammals. Our study provided data on the mechanism for PA mutations to accumulate during avian influenza virus evolution and extend the viral host range. IMPORTANCE Clade 2.2.1 avian influenza viruses (H5N1) are unique to Egypt and have caused the highest number of human H5N1 influenza cases worldwide, presenting a serious global public health threat. These viruses may have the greatest evolutionary potential for adaptation from avian hosts to human hosts. Using a comprehensive phylogenetic approach, we identified several novel clade 2.2.1 virus polymerase mutations that increased viral replication in vitro in human cells and in vivo in mice. These mutations were in the polymerase PA subunit and acted cooperatively with the E627K mutation in the PB2 polymerase subunit to provide higher replication in contemporary clade 2.2.1.2 viruses than in ancestral clade 2.2.1 viruses. These data indicated that ongoing clade 2.2.1 dissemination in the field has driven PA mutations to modify viral replication to enable host range expansion, with a higher public health risk for humans.

scholarly journals Inhibition of Influenza Virus Infection by a Novel Antiviral Peptide That Targets Viral Attachment to Cells

2006 ◽  
Vol 80 (24) ◽  
pp. 11960-11967 ◽  
Author(s):  
Jeremy C. Jones ◽  
Elizabeth A. Turpin ◽  
Hermann Bultmann ◽  
Curtis R. Brandt ◽  
Stacey Schultz-Cherry
Keyword(s):  
Influenza A ◽  
Signal Sequence ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Influenza A Viruses ◽  
Viral Attachment ◽  
H5n1 Influenza ◽  
Eb Peptide

ABSTRACT Influenza A viruses continue to cause widespread morbidity and mortality. There is an added concern that the highly pathogenic H5N1 influenza A viruses, currently found throughout many parts of the world, represent a serious public health threat and may result in a pandemic. Intervention strategies to halt an influenza epidemic or pandemic are a high priority, with an emphasis on vaccines and antiviral drugs. In these studies, we demonstrate that a 20-amino-acid peptide (EB, for entry blocker) derived from the signal sequence of fibroblast growth factor 4 exhibits broad-spectrum antiviral activity against influenza viruses including the H5N1 subtype in vitro. The EB peptide was protective in vivo, even when administered postinfection. Mechanistically, the EB peptide inhibits the attachment to the cellular receptor, preventing infection. Further studies demonstrated that the EB peptide specifically binds to the viral hemagglutinin protein. This novel peptide has potential value as a reagent to study virus attachment and as a future therapeutic.

scholarly journals A broad and potent H1-specific human monoclonal antibody produced in plants prevents influenza virus infection and transmission in guinea pigs

2020 ◽  
Author(s):  
Jun-Gyu Park ◽  
Chengjin Ye ◽  
Michael S. Piepenbrink ◽  
Aitor Nogales ◽  
Haifeng Wang ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Guinea Pigs ◽  
Mammalian Cells ◽  
Influenza A ◽  
Human Monoclonal Antibody ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Antigenic Drift

AbstractAlthough seasonal influenza vaccines block most predominant influenza types and subtypes, humans still remain vulnerable to waves of seasonal and new potential pandemic influenza viruses for which no immunity may exist because of viral antigenic drift and/or shift, respectively. Previously, we have described a human monoclonal antibody (hMAb), KPF1, which was produced in human embryonic kidney 293T cells (KPF1-HEK) with broad and potent neutralizing activity against H1N1 influenza A viruses (IAV) in vitro, and prophylactic and therapeutic activities in vivo. In this study, we produced hMAb KPF1 in tobacco plants (KPF1-Antx) and demonstrate how the plant-produced KPF1-Antx hMAb possesses similar biological activity compared with the mammalian produced KPF1-HEK hMAb. KPF1-Antx hMAb shows broad binding to recombinant HA proteins and H1N1 IAV, including A/California/04/2009 (pH1N1) in vitro, that are comparable to those observed with KPF1-HEK hMAb. Importantly, prophylactic administration of KPF1-Antx hMAb to guinea pigs prevented pH1N1 infection and transmission in both prophylactic and therapeutic experiments, substantiating its clinical potential to prevent and treat H1N1 infections. Collectively, this study demonstrates, for the first time, that plant-produced influenza hMAbs have similar in vitro and in vivo biological properties to those produced in mammalian cells. Because of the many advantages of plant-produced hMAbs, such as rapid batch production, low cost, and the absence of mammalian cell products, they represent an alternative strategy for the production of immunotherapeutics for the treatment of influenza viral infections, including emerging seasonal and/or pandemic strains.

scholarly journals Cloning recombinant pHW2000 vector carrying the HA gene for preparation of the primary influenza A/H5N1 vaccine strain

2017 ◽  
Vol 33 (1S) ◽  
Author(s):  
Nguyen Thi Thu Hang ◽  
Hoang Thi Thu Hang ◽  
Nguyen Hung Chi ◽  
Chu Hoang Ha ◽  
Nguyen Trung Nam
Keyword(s):  
Amino Acids ◽  
Avian Influenza ◽  
Influenza A ◽  
Reverse Genetics ◽  
Genetic Relationships ◽  
Highly Pathogenic ◽  
Ha Gene ◽  
H5n1 Influenza ◽  
Hpai H5n1 ◽  
Clade 2.3.2.1C

Influenza A/H5N1 virus evolves rapidly and generate new variants, therefore it is essential to develop effective vaccines against the currently circulating influenza strains. Among clades and subclades of highly pathogenic avian influenza (HPAI) H5N1 viruses circulating in Vietnam, H5N1 clade 1.1 and clade 2.3.2.1c possess genetic relationships to many strains of influenza; thus they are suggested to be used for producing vaccines against avian influenza. In this article, two HA gene segments of two types of A/H5N1 influenza clade have been designed: HA clade 1.1 gene consists 1825 nucleotides encoding 565 amino acids, HA clade 2.3.2.1c gene consists 1822 nucleotides, encoding 564 amino acids. Most importantly, nucleotide sequence of the pathogenic region of HA was removed. Each of the two HA segments corresponding to the two clades were successfully cloned into pHW2000 vector and will be used as a candidate for production of avian influenza vaccines using reverse genetics technique.  

scholarly journals PB2 Residue 271 Plays a Key Role in Enhanced Polymerase Activity of Influenza A Viruses in Mammalian Host Cells

2010 ◽  
Vol 84 (9) ◽  
pp. 4395-4406 ◽  
Author(s):  
Kendra A. Bussey ◽  
Tatiana L. Bousse ◽  
Emily A. Desmet ◽  
Baek Kim ◽  
Toru Takimoto
Keyword(s):  
Mammalian Cells ◽  
Influenza A ◽  
Virus Titer ◽  
Polymerase Activity ◽  
Influenza Viruses ◽  
Host Cells ◽  
Mammalian Host ◽  
Influenza A Viruses ◽  
H5n1 Influenza ◽  
Avian Viruses

ABSTRACT The direct infection of humans with highly pathogenic avian H5N1 influenza viruses has suggested viral mutation as one mechanism for the emergence of novel human influenza A viruses. Although the polymerase complex is known to be a key component in host adaptation, mutations that enhance the polymerase activity of avian viruses in mammalian hosts are not fully characterized. The genomic comparison of influenza A virus isolates has identified highly conserved residues in influenza proteins that are specific to either human or avian viruses, including 10 residues in PB2. We characterized the activity of avian polymerase complexes containing avian-to-human mutations at these conserved PB2 residues and found that, in addition to the E627K mutation, the PB2 mutation T271A enhances polymerase activity in human cells. We confirmed the effects of the T271A mutation using recombinant WSN viruses containing avian NP and polymerase genes with wild-type (WT) or mutant PB2. The 271A virus showed enhanced growth compared to that of the WT in mammalian cells in vitro. The 271A mutant did not increase viral pathogenicity significantly in mice compared to that of the 627K mutant, but it did enhance the lung virus titer. Also, cell infiltration was more evident in lungs of 271A-infected mice than in those of the WT. Interestingly, the avian-derived PB2 of the 2009 pandemic H1N1 influenza virus has 271A. The characterization of the polymerase activity of A/California/04/2009 (H1N1) and corresponding PB2 mutants indicates that the high polymerase activity of the pandemic strain in mammalian cells is, in part, dependent on 271A. Our results clearly indicate the contribution of PB2 amino acid 271 to enhanced polymerase activity and viral growth in mammalian hosts.

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

Viruses ◽  
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.

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

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.

scholarly journals The Polymerase Acidic Protein Gene of Influenza A Virus Contributes to Pathogenicity in a Mouse Model

2009 ◽  
Vol 83 (23) ◽  
pp. 12325-12335 ◽  
Author(s):  
Min-Suk Song ◽  
Philippe Noriel Q. Pascua ◽  
Jun Han Lee ◽  
Yun Hee Baek ◽  
Ok-Jun Lee ◽  
...  
Keyword(s):  
Avian Influenza ◽  
Mammalian Cells ◽  
Influenza A ◽  
Lethal Dose ◽  
Influenza Viruses ◽  
Mammalian Host ◽  
Viral Gene ◽  
Avian Influenza Viruses ◽  
Range Restriction ◽  
Viral Genes

ABSTRACT Adaptation of influenza A viruses to a new host species usually involves the mutation of one or more of the eight viral gene segments, and the molecular basis for host range restriction is still poorly understood. To investigate the molecular changes that occur during adaptation of a low-pathogenic avian influenza virus subtype commonly isolated from migratory birds to a mammalian host, we serially passaged the avirulent wild-bird H5N2 strain A/Aquatic bird/Korea/W81/05 (W81) in the lungs of mice. The resulting mouse-adapted strain (ma81) was highly virulent (50% mouse lethal dose = 2.6 log10 50% tissue culture infective dose) and highly lethal. Nonconserved mutations were observed in six viral genes (those for PB2, PB1, PA, HA, NA, and M). Reverse genetic experiments substituting viral genes and mutations demonstrated that the PA gene was a determinant of the enhanced virulence in mice and that a Thr-to-Iso substitution at position 97 of PA played a key role. In growth kinetics studies, ma81 showed enhanced replication in mammalian but not avian cell lines; the PA97I mutation in strain W81 increased its replicative fitness in mice but not in chickens. The high virulence associated with the PA97I mutation in mice corresponded to considerably enhanced polymerase activity in mammalian cells. Furthermore, this characteristic mutation is not conserved among avian influenza viruses but is prevalent among mouse-adapted strains, indicating a host-dependent mutation. To our knowledge, this is the first study that the isoleucine residue at position 97 in PA plays a key role in enhanced virulence in mice and is implicated in the adaptation of avian influenza viruses to mammalian hosts.

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