EVIDENCE FOR GENETIC INTERACTION BETWEEN NON-INFECTIOUS AND INFECTIOUS INFLUENZA A VIRUSES

Influenza virus rendered non-infectious by ultraviolet irradiation retained ability to "exchange" genetic traits with related virus, resulting in recombined forms. Sedimentation studies indicated association of recombinining activity with particles approximately the size of influenza virus. Genetic activity was not demonstrated when virus was more severely disrupted in attempts to observe phenomena analogous to bacterial transformation. Irradiated virus was also shown to remain capable of genetic exchange for at least 4 days after inoculation into embryonate eggs. In contrast infectious virus becomes insusceptible to genetic exchange after 1 hour incubation in eggs. The importance of this delayed recombination phenomenon to processes of virus evolution and influenza strain variation was discussed.

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Chimeric Hemagglutinin-Based Live-Attenuated Vaccines Confer Durable Protective Immunity against Influenza A Viruses in a Preclinical Ferret Model

Vaccines ◽

10.3390/vaccines9010040 ◽

2021 ◽

Vol 9 (1) ◽

pp. 40

Author(s):

Wen-Chun Liu ◽

Raffael Nachbagauer ◽

Daniel Stadlbauer ◽

Shirin Strohmeier ◽

Alicia Solórzano ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Influenza Virus Infection ◽

Influenza Virus Vaccine ◽

Antibody Responses ◽

Upper Respiratory Tract ◽

Influenza A Viruses ◽

Humoral And Cellular Immunity ◽

Stalk Domain ◽

One Year

Epidemic or pandemic influenza can annually cause significant morbidity and mortality in humans. We developed novel chimeric hemagglutinin (cHA)-based universal influenza virus vaccines, which contain a conserved HA stalk domain from a 2009 pandemic H1N1 (pH1N1) strain combined with globular head domains from avian influenza A viruses. Our previous reports demonstrated that prime-boost sequential immunizations induced robust antibody responses directed toward the conserved HA stalk domain in ferrets. Herein, we further followed vaccinated animals for one year to compare the efficacy and durability of these vaccines in the preclinical ferret model of influenza. Although all cHA-based immunization regimens induced durable HA stalk-specific and heterosubtypic antibody responses in ferrets, sequential immunization with live-attenuated influenza virus vaccines (LAIV-LAIV) conferred the best protection against upper respiratory tract infection by a pH1N1 influenza A virus. The findings from this study suggest that our sequential immunization strategy for a cHA-based universal influenza virus vaccine provides durable protective humoral and cellular immunity against influenza virus infection.

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Influenza: An Emerging and Re-emerging Public Health Threat in Nepal

Annals of Clinical Chemistry and Laboratory Medicine ◽

10.3126/acclm.v3i2.20737 ◽

2018 ◽

Vol 3 (2) ◽

pp. 1-2

Author(s):

Bishnu Prasad Upadhyay

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Winter Season ◽

Emerging Infectious Diseases ◽

Influenza Viruses ◽

Influenza B ◽

Influenza A Viruses ◽

Influenza A H1n1 ◽

New Variant ◽

Seasonal Epidemics

Influenza virus type A and B are responsible for seasonal epidemics as well as pandemics in human. Influenza A viruses are further divided into two major groups namely, low pathogenic seasonal influenza (A/H1N1, A/H1N1 pdm09, A/H3N2) and highly pathogenic influenza virus (H5N1, H5N6, H7N9) on the basis of two surface antigens: hemagglutinin (HA) and neuraminidase (NA). Mutations, including substitutions, deletions, and insertions, are one of the most important mechanisms for producing new variant of influenza viruses. During the last 30 years; more than 50 viral threat has been evolved in South-East Asian countriesof them influenza is one of the major emerging and re-emerging infectious diseases of global concern. Similar to tropical and sub-tropical countries of Southeast Asia; circulation of A/H1N1 pdm09, A/H3N2 and influenza B has been circulating throughout the year with the peak during July-November in Nepal. However; the rate of infection transmission reach peak during the post-rain and winter season of Nepal.

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Characterization of H9N2 influenza A viruses isolated from chicken products imported into Japan from China

Epidemiology and Infection ◽

10.1017/s0950268806006728 ◽

2006 ◽

Vol 135 (3) ◽

pp. 386-391 ◽

Cited By ~ 13

Author(s):

M. MASE ◽

M. ETO ◽

K. IMAI ◽

K. TSUKAMOTO ◽

S. YAMAGUCHI

Keyword(s):

Influenza Virus ◽

Amino Acid ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Influenza A ◽

H9n2 Virus ◽

Amino Acid Substitutions ◽

Influenza A Viruses ◽

Potential Sources

We characterized eleven H9N2 influenza A viruses isolated from chicken products imported from China. Genetically they were classified into six distinct genotypes, including five already known genotypes and one novel genotype. This suggested that such multiple genotypes of the H9N2 virus have possibly already become widespread and endemic in China. Two isolates have amino-acid substitutions that confer resistance to amantadine in the M2 region, and this supported the evidence that this mutation might be a result of the wide application of amantadine for avian influenza treatment in China. These findings emphasize the importance of surveillance for avian influenza virus in this region, and of quarantining imported chicken products as potential sources for the introduction of influenza virus.

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Plasticity of the Influenza Virus H5 HA Protein

mBio ◽

10.1128/mbio.03324-20 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Huihui Kong ◽

David F. Burke ◽

Tiago Jose da Silva Lopes ◽

Kosuke Takada ◽

Masaki Imai ◽

...

Keyword(s):

Influenza Virus ◽

Amino Acid ◽

Mammalian Cells ◽

Influenza A ◽

Viral Antigen ◽

Influenza Viruses ◽

Influenza A Viruses ◽

Highly Pathogenic ◽

Antigenic Properties ◽

Ha Protein

ABSTRACT Since the emergence of highly pathogenic avian influenza viruses of the H5 subtype, the major viral antigen, hemagglutinin (HA), has undergone constant evolution, resulting in numerous genetic and antigenic (sub)clades. To explore the consequences of amino acid changes at sites that may affect the antigenicity of H5 viruses, we simultaneously mutated 17 amino acid positions of an H5 HA by using a synthetic gene library that, theoretically, encodes all combinations of the 20 amino acids at the 17 positions. All 251 mutant viruses sequenced possessed ≥13 amino acid substitutions in HA, demonstrating that the targeted sites can accommodate a substantial number of mutations. Selection with ferret sera raised against H5 viruses of different clades resulted in the isolation of 39 genotypes. Further analysis of seven variants demonstrated that they were antigenically different from the parental virus and replicated efficiently in mammalian cells. Our data demonstrate the substantial plasticity of the influenza virus H5 HA protein, which may lead to novel antigenic variants. IMPORTANCE The HA protein of influenza A viruses is the major viral antigen. In this study, we simultaneously introduced mutations at 17 amino acid positions of an H5 HA expected to affect antigenicity. Viruses with ≥13 amino acid changes in HA were viable, and some had altered antigenic properties. H5 HA can therefore accommodate many mutations in regions that affect antigenicity. The substantial plasticity of H5 HA may facilitate the emergence of novel antigenic variants.

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Biological Cloth Face Coverings - The Reduction of SARS-CoV-2 and Influenza (H1N1) Infectivity by ViruferrinTM Treatment

10.20944/preprints202104.0050.v1 ◽

2021 ◽

Author(s):

Emily Medina Magues ◽

Anna Stedman ◽

Paul Hope ◽

Jorge E. Osorio

Keyword(s):

Influenza A ◽

Infectious Virus ◽

Positive Control ◽

Influenza A Viruses ◽

Virus Particles ◽

Significant Difference ◽

Untreated Material ◽

Fabric Material ◽

Influenza H1n1 ◽

Time Point

Fabric material was coated with Viruferrin™ and tested for its inactivating properties against the pandemic severe acute respiratory syndrome 2 (SARS-CoV-2) and influenza A viruses. A statistically significant (p<0.0001) decrease in the number of infectious virus particles exposed to Viruferrin-treated fabric when compared with the cotton control for both SARS-CoV-2 and influenza A viruses was observed. For both SARS-CoV-2 and influenza A, Viruferrin-treated fabrics experienced a > 99% virus reduction without saliva after five minutes of contact when compared to the positive control at time point 0. Furthermore, the reusability of the Viruferrin treated fabric was demonstrated by stability for up to 10 washes. The level of anti-viral (SARS-CoV-2) activity remained constant from 5 to 10 washes and demonstrated a significant difference (p<0.0001) from the unwashed untreated material. Applications for this treated fabric are far-reaching, and as a biological face covering offers not only a unique 2-way protection but also is unlikely to cause onward touch transmission.

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Broadly Reactive H2 Hemagglutinin Vaccines Elicit Cross-Reactive Antibodies in Ferrets Preimmune to Seasonal Influenza A Viruses

mSphere ◽

10.1128/msphere.00052-21 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Z. Beau Reneer ◽

Amanda L. Skarlupka ◽

Parker J. Jamieson ◽

Ted M. Ross

Keyword(s):

Influenza Virus ◽

Immune Responses ◽

Recombinant Proteins ◽

Human Population ◽

Influenza A ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Wild Type ◽

Influenza A Viruses ◽

Global Pandemic

ABSTRACT Influenza vaccines have traditionally been tested in naive mice and ferrets. However, humans are first exposed to influenza viruses within the first few years of their lives. Therefore, there is a pressing need to test influenza virus vaccines in animal models that have been previously exposed to influenza viruses before being vaccinated. In this study, previously described H2 computationally optimized broadly reactive antigen (COBRA) hemagglutinin (HA) vaccines (Z1 and Z5) were tested in influenza virus “preimmune” ferret models. Ferrets were infected with historical, seasonal influenza viruses to establish preimmunity. These preimmune ferrets were then vaccinated with either COBRA H2 HA recombinant proteins or wild-type H2 HA recombinant proteins in a prime-boost regimen. A set of naive preimmune or nonpreimmune ferrets were also vaccinated to control for the effects of the multiple different preimmunities. All of the ferrets were then challenged with a swine H2N3 influenza virus. Ferrets with preexisting immune responses influenced recombinant H2 HA-elicited antibodies following vaccination, as measured by hemagglutination inhibition (HAI) and classical neutralization assays. Having both H3N2 and H1N1 immunological memory regardless of the order of exposure significantly decreased viral nasal wash titers and completely protected all ferrets from both morbidity and mortality, including the mock-vaccinated ferrets in the group. While the vast majority of the preimmune ferrets were protected from both morbidity and mortality across all of the different preimmunities, the Z1 COBRA HA-vaccinated ferrets had significantly higher antibody titers and recognized the highest number of H2 influenza viruses in a classical neutralization assay compared to the other H2 HA vaccines. IMPORTANCE H1N1 and H3N2 influenza viruses have cocirculated in the human population since 1977. Nearly every human alive today has antibodies and memory B and T cells against these two subtypes of influenza viruses. H2N2 influenza viruses caused the 1957 global pandemic and people born after 1968 have never been exposed to H2 influenza viruses. It is quite likely that a future H2 influenza virus could transmit within the human population and start a new global pandemic, since the majority of people alive today are immunologically naive to viruses of this subtype. Therefore, an effective vaccine for H2 influenza viruses should be tested in an animal model with previous exposure to influenza viruses that have circulated in humans. Ferrets were infected with historical influenza A viruses to more accurately mimic the immune responses in people who have preexisting immune responses to seasonal influenza viruses. In this study, preimmune ferrets were vaccinated with wild-type (WT) and COBRA H2 recombinant HA proteins in order to examine the effects that preexisting immunity to seasonal human influenza viruses have on the elicitation of broadly cross-reactive antibodies from heterologous vaccination.

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Large-Scale Sequence Analysis of M Gene of Influenza A Viruses from Different Species: Mechanisms for Emergence and Spread of Amantadine Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00650-09 ◽

2009 ◽

Vol 53 (10) ◽

pp. 4457-4463 ◽

Cited By ~ 64

Author(s):

Yuki Furuse ◽

Akira Suzuki ◽

Hitoshi Oshitani

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Drug Resistant ◽

Human Influenza ◽

Influenza A Viruses ◽

M Gene ◽

Drug Pressure ◽

Human Influenza Virus ◽

Selective Pressures ◽

Amantadine Resistance

ABSTRACT Influenza A virus infects many species, and amantadine is used as an antiviral agent. Recently, a substantial increase in amantadine-resistant strains has been reported, most of which have a substitution at amino acid position 31 in the M2 gene. Understanding the mechanism responsible for the emergence and spread of antiviral resistance is important for developing a treatment protocol for seasonal influenza and for deciding on a policy for antiviral stockpiling for pandemic influenza. The present study was conducted to identify the existence of drug pressure on the emergence and spread of amantadine-resistant influenza A viruses. We analyzed data on more than 5,000 virus sequences and constructed a phylogenetic tree to calculate selective pressures on sites in the M2 gene associated with amantadine resistance (positions 26, 27, 30, and 31) among different hosts. The phylogenetic tree revealed that the emergence and spread of the drug-resistant M gene in different hosts and subtypes were independent and not through reassortment. For human influenza virus, positive selection was detected only at position 27. Selective pressures on the sites were not always higher for human influenza virus than for viruses of other hosts. Additionally, selective pressure on position 31 did not increase after the introduction of amantadine. Although there is a possibility of drug pressure on human influenza virus, we could not find positive pressure on position 31. Because the recent rapid increase in drug-resistant virus is associated with the substitution at position 31, the resistance may not be related to drug use.

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Bayesian inference of antigenic and non-antigenic variables from haemagglutination inhibition assays for influenza surveillance

Royal Society Open Science ◽

10.1098/rsos.180113 ◽

2018 ◽

Vol 5 (7) ◽

pp. 180113

Author(s):

Emmanuel S. Adabor ◽

Wilfred Ndifon

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Bayesian Method ◽

Haemagglutination Inhibition ◽

Virus Evolution ◽

Influenza Viruses ◽

Influenza Surveillance ◽

Antigenic Properties ◽

Analytical Work

Haemagglutination inhibition (HI) assays are typically used for comparing and characterizing influenza viruses. Data obtained from the assays (titres) are used quantitatively to determine antigenic differences between influenza strains. However, the use of these titres has been criticized as they sometimes fail to capture accurate antigenic differences between strains. Our previous analytical work revealed how antigenic and non-antigenic variables contribute to the titres. Building on this previous work, we have developed a Bayesian method for decoupling antigenic and non-antigenic contributions to the titres in this paper. We apply this method to a compendium of HI titres of influenza A (H3N2) viruses curated from 1968 to 2016. Remarkably, the results of this fit indicate that the non-antigenic variable, which is inversely correlated with viral avidity for the red blood cells used in HI assays, oscillates during the course of influenza virus evolution, with a period that corresponds roughly to the timescale on which antigenic variants replace each other. Together, the results suggest that the new Bayesian method is applicable to the analysis of long-term dynamics of both antigenic and non-antigenic properties of influenza virus.

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Spatiotemporal Distribution and Evolution of the A/H1N1 2009 Pandemic Influenza Virus in Pigs in France from 2009 to 2017: Identification of a Potential Swine-Specific Lineage

Journal of Virology ◽

10.1128/jvi.00988-18 ◽

2018 ◽

Vol 92 (24) ◽

Cited By ~ 12

Author(s):

Amélie Chastagner ◽

Séverine Hervé ◽

Emilie Bonin ◽

Stéphane Quéguiner ◽

Edouard Hirchaud ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A ◽

Phylogenetic Analyses ◽

Swine Influenza ◽

H1n1 Influenza ◽

Antigenic Drift ◽

Influenza A Viruses ◽

Evolutionary Patterns ◽

Increased Risk ◽

Na Sequences

ABSTRACT The H1N1 influenza virus responsible for the most recent pandemic in 2009 (H1N1pdm) has spread to swine populations worldwide while it replaced the previous seasonal H1N1 virus in humans. In France, surveillance of swine influenza A viruses in pig herds with respiratory outbreaks led to the detection of 44 H1N1pdm strains between 2009 and 2017, regardless of the season, and findings were not correlated with pig density. From these isolates, 17 whole-genome sequences were obtained, as were 6 additional hemagglutinin (HA)/neuraminidase (NA) sequences, in order to perform spatial and temporal analyses of genetic diversity and to compare evolutionary patterns of H1N1pdm in pigs to patterns for human strains. Following mutation accumulation and fixation over time, phylogenetic analyses revealed for the first time the divergence of a swine-specific genogroup within the H1N1pdm lineage. The divergence is thought to have occurred around 2011, although this was demonstrated only through strains isolated in 2015 to 2016 in the southern half of France. To date, these H1N1pdm swine strains have not been related to any increased virulence in swine herds and have not exhibited any antigenic drift compared to seasonal human strains. However, further monitoring is encouraged, as diverging evolutionary patterns in these two species, i.e., swine and humans, may lead to the emergence of viruses with a potentially higher risk to both animal and human health.IMPORTANCE Pigs are a “mixing vessel” for influenza A viruses (IAVs) because of their ability to be infected by avian and human IAVs and their propensity to facilitate viral genomic reassortment events. Also, as IAVs may evolve differently in swine and humans, pigs can become a reservoir for old human strains against which the human population has become immunologically naive. Thus, viruses from the novel swine-specific H1N1pdm genogroup may continue to diverge from seasonal H1N1pdm strains and/or from other H1N1pdm viruses infecting pigs and lead to the emergence of viruses that would not be covered by human vaccines and/or swine vaccines based on antigens closely related to the original H1N1pdm virus. This discovery confirms the importance of encouraging swine IAV monitoring because H1N1pdm swine viruses could carry an increased risk to both human and swine health in the future as a whole H1N1pdm virus or gene provider in subsequent reassortant viruses.

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International Laboratory Comparison of Influenza Microneutralization Assays for A(H1N1)pdm09, A(H3N2), and A(H5N1) Influenza Viruses by CONSISE

Clinical and Vaccine Immunology ◽

10.1128/cvi.00278-15 ◽

2015 ◽

Vol 22 (8) ◽

pp. 957-964 ◽

Cited By ~ 28

Author(s):

Karen L. Laurie ◽

Othmar G. Engelhardt ◽

John Wood ◽

Alan Heath ◽

Jacqueline M. Katz ◽

...

Keyword(s):

Influenza Virus ◽

Incubation Time ◽

Influenza A ◽

Influenza Viruses ◽

Enzyme Linked Immunosorbent Assay ◽

Influenza A Viruses ◽

H5n1 Influenza ◽

The World ◽

International Laboratory ◽

The Impact

ABSTRACTThe microneutralization assay is commonly used to detect antibodies to influenza virus, and multiple protocols are used worldwide. These protocols differ in the incubation time of the assay as well as in the order of specific steps, and even within protocols there are often further adjustments in individual laboratories. The impact these protocol variations have on influenza serology data is unclear. Thus, a laboratory comparison of the 2-day enzyme-linked immunosorbent assay (ELISA) and 3-day hemagglutination (HA) microneutralization (MN) protocols, using A(H1N1)pdm09, A(H3N2), and A(H5N1) viruses, was performed by the CONSISE Laboratory Working Group. Individual laboratories performed both assay protocols, on multiple occasions, using different serum panels. Thirteen laboratories from around the world participated. Within each laboratory, serum sample titers for the different assay protocols were compared between assays to determine the sensitivity of each assay and were compared between replicates to assess the reproducibility of each protocol for each laboratory. There was good correlation of the results obtained using the two assay protocols in most laboratories, indicating that these assays may be interchangeable for detecting antibodies to the influenza A viruses included in this study. Importantly, participating laboratories have aligned their methodologies to the CONSISE consensus 2-day ELISA and 3-day HA MN assay protocols to enable better correlation of these assays in the future.

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