Epidemiologic Study of Influenza Infection in Okinawa, Japan, from 2001 to 2007: Changing Patterns of Seasonality and Prevalence of Amantadine-Resistant Influenza A Virus

BACKGROUND: The application of CRISPR/Cas9 is one of the most rapidly developing areas in biotechnology. This method was used to obtain clones of а human origin cell line with knockout of one or more genes of the IFITM family, representing host restriction factors for influenza infection. Amphotericin B has previously been shown to promote influenza infection by blocking IFITM3 function. AIM: The aim of this study was to evaluate the effect of amphotericin B on the sensitivity of IFITM knockout cells to influenza A virus infection. MATERIALS AND METHODS: WI-38 VA-13 cells and mutant clones with IFITM3 knockout (F3 clone) or IFITM1, IFITM3 knockout (clone E12) were infected with influenza virus A/PR/8/34 (H1N1) in the presence or absence of amphotericin B. Forty-four hours after infection, the culture medium was taken to determine the infectious activity of the virus by titration in the MDCK cell culture, as well as the hemagglutinating activity of the virus. The infected cells were stained with fluorescently labeled antibodies against the viral NP protein, and the number of NP-positive cells was determined by flow cytometry. RESULTS: The addition of amphotericin B increased the hemagglutinating and infectious activity of the virus in WI-38 VA-13cells, while the difference was insignificant for clones with IFITM gene knockout. A similar dependency was obtained for the percent of infected cells. CONCLUSIONS: Mutant cells with a knockout of one or several genes of the IFITM family were equally susceptible to influenza infection regardless of the addition of amphotericin B, which confirms the crucial importance of a defect in the IFITM3 protein in increasing the permissiveness of cells to influenza A virus.

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Routine blood parameters are helpful for early identification of influenza infection in children

10.21203/rs.3.rs-54705/v2 ◽

2020 ◽

Author(s):

Ronghe Zhu ◽

Cuie Chen ◽

Qiu Wang ◽

Xixi Zhang ◽

Chaosheng Lu ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Influenza A Virus ◽

Early Identification ◽

Influenza A ◽

Influenza Infection ◽

Influenza Virus Infection ◽

Cutoff Value ◽

Routine Blood ◽

Influenza A Virus Infection

Abstract Purpose Routine blood parameters, such as the lymphocyte (LYM) count, platelet (PLT) count, lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), LYM*PLT and mean platelet volume-to-platelet ratio (MPV/PLT), are widely used to predict the prognosis of infectious diseases. We aimed to explore the value of these parameters in the early identification of influenza virus infection in children.Methods We conducted a single-center, retrospective, observational study of fever with influenza-like symptoms in pediatric outpatients from different age groups and evaluated the predictive value of various routine blood parameters measured within 48 hours of the onset of fever for influenza virus infection.Results The LYM count, PLT count, LMR and LYM*PLT were lower, and the NLR and MPV/PLT were higher in children with an influenza infection (PCR-confirmed and symptomatic). The LYM count, LMR and LYM*PLT in the influenza infection group were lower in the 1- to 6-year-old subgroup, and the LMR and LYM*PLT in the influenza infection group were lower in the >6-year-old subgroup. In the 1- to 6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.75, the sensitivity was 81.87%, the specificity was 84.31%, and the area under the curve (AUC) was 0.886; the cutoff value of the LMR for predicting influenza B virus infection was 3.71, the sensitivity was 73.58%, the specificity was 84.31%, and the AUC was 0.843. In the >6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.05, the sensitivity was 89.27%, the specificity was 89.61%, and the AUC was 0.949; the cutoff value of the LMR for predicting influenza B virus infection was 2.88, the sensitivity was 83.19%, the specificity was 92.21%, and the AUC was 0.924.Conclusions Routine blood tests are simple, inexpensive and easy to perform, and they are useful for the early identification of influenza virus infection in children. The LMR had the strongest predictive value for influenza virus infection in children older than 1 year, particularly influenza A virus infection.

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Influenza PB1-F2 Inhibits Avian MAVS Signaling

Viruses ◽

10.3390/v12040409 ◽

2020 ◽

Vol 12 (4) ◽

pp. 409

Author(s):

Yanna Xiao ◽

Danyel Evseev ◽

Chase A. Stevens ◽

Adam Moghrabi ◽

Domingo Miranzo-Navarro ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Virus Strain ◽

Species Interactions ◽

Influenza A ◽

Promoter Activity ◽

Interferon Beta ◽

Influenza Infection ◽

Adaptor Protein ◽

Human Cells

RIG-I plays an essential role in the duck innate immune response to influenza infection. RIG-I engages the critical adaptor protein mitochondrial antiviral signaling (MAVS) to activate the downstream signaling pathway. The influenza A virus non-structural protein PB1-F2 interacts with MAVS in human cells to inhibit interferon production. As duck and human MAVS share only 28% amino acid similarity, it is not known whether the influenza virus can similarly inhibit MAVS signaling in avian cells. Using confocal microscopy we show that MAVS and the constitutively active N-terminal end of duck RIG-I (2CARD) co-localize in DF-1 cells, and duck MAVS is pulled down with GST-2CARD. We establish that either GST-2CARD, or duck MAVS can initiate innate signaling in chicken cells and their co-transfection augments interferon-beta promoter activity. Demonstrating the limits of cross-species interactions, duck RIG-I 2CARD initiates MAVS signaling in chicken cells, but works poorly in human cells. The D122A mutation of human 2CARD abrogates signaling by affecting MAVS engagement, and the reciprocal A120D mutation in duck 2CARD improves signaling in human cells. We show mitochondrial localization of PB1-F2 from influenza A virus strain A/Puerto Rico/8/1934 (H1N1; PR8), and its co-localization and co-immunoprecipitation with duck MAVS. PB1-F2 inhibits interferon-beta promoter activity induced by overexpression of either duck RIG-I 2CARD, full-length duck RIG-I, or duck MAVS. Finally, we show that the effect of PB1-F2 on mitochondria abrogates TRIM25-mediated ubiquitination of RIG-I CARD in both human and avian cells, while an NS1 variant from the PR8 influenza virus strain does not.

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RNA-Sequencing-Based Transcriptomic Analysis Reveals a Role for Annexin-A1 in Classical and Influenza A Virus-Induced Autophagy

Cells ◽

10.3390/cells9061399 ◽

2020 ◽

Vol 9 (6) ◽

pp. 1399 ◽

Cited By ~ 1

Author(s):

Jianzhou Cui ◽

Dhakshayini Morgan ◽

Dao Han Cheng ◽

Sok Lin Foo ◽

Gracemary L. R. Yap ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Infection ◽

Critical Role ◽

Mtor Inhibitors ◽

Influenza Viruses ◽

Annexin A1 ◽

Underlying Mechanisms

Influenza viruses have been shown to use autophagy for their survival. However, the proteins and mechanisms involved in the autophagic process triggered by the influenza virus are unclear. Annexin-A1 (ANXA1) is an immunomodulatory protein involved in the regulation of the immune response and Influenza A virus (IAV) replication. In this study, using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 (CRISPR associated protein 9) deletion of ANXA1, combined with the next-generation sequencing, we systematically analyzed the critical role of ANXA1 in IAV infection as well as the detailed processes governing IAV infection, such as macroautophagy. A number of differentially expressed genes were uniquely expressed in influenza A virus-infected A549 parental cells and A549 ∆ANXA1 cells, which were enriched in the immune system and infection-related pathways. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway revealed the role of ANXA1 in autophagy. To validate this, the effect of mechanistic target of rapamycin (mTOR) inhibitors, starvation and influenza infection on autophagy was determined, and our results demonstrate that ANXA1 enhances autophagy induced by conventional autophagy inducers and influenza virus. These results will help us to understand the underlying mechanisms of IAV infection and provide a potential therapeutic target for restricting influenza viral replication and infection.

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Long-Lasting Mucosal and Systemic Immunity against Influenza A Virus Is Significantly Prolonged and Protective by Nasal Whole Influenza Immunization with Mucosal Adjuvant N3 and DNA-Plasmid Expressing Flagellin in Aging In- and Outbred Mice

Vaccines ◽

10.3390/vaccines7030064 ◽

2019 ◽

Vol 7 (3) ◽

pp. 64 ◽

Cited By ~ 2

Author(s):

Jorma Hinkula ◽

Sanna Nyström ◽

Claudia Devito ◽

Andreas Bråve ◽

Steven E. Applequist

Keyword(s):

Immune Responses ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Infection ◽

Inbred Mouse ◽

Herd Immunity ◽

Serum Antibody ◽

Mouse Strains ◽

Virus Challenge ◽

Influenza A H1n1

Background: Vaccination is commonly used to prevent and control influenza infection in humans. However, improvements in the ease of delivery and strength of immunogenicity could markedly improve herd immunity. The aim of this pre-clinical study is to test the potential improvements to existing intranasal delivery of formalin-inactivated whole Influenza A vaccines (WIV) by formulation with a cationic lipid-based adjuvant (N3). Additionally, we combined WIV and N3 with a DNA-encoded TLR5 agonist secreted flagellin (pFliC(-gly)) as an adjuvant, as this adjuvant has previously been shown to improve the effectiveness of plasmid-encoded DNA antigens. Methods: Outbred and inbred mouse strains were intranasally immunized with unadjuvanted WIV A/H1N1/SI 2006 or WIV that was formulated with N3 alone. Additional groups were immunized with WIV and N3 adjuvant combined with pFliC(-gly). Homo and heterotypic humoral anti-WIV immune responses were assayed from serum and lung by ELISA and hemagglutination inhibition assay. Homo and heterotypic cellular immune responses to WIV and Influenza A NP were also determined. Results: WIV combined with N3 lipid adjuvant the pFliC(-gly) significantly increased homotypic influenza specific serum antibody responses (>200-fold), increased the IgG2 responses, indicating a mixed Th1/Th2-type immunity, and increased the HAI-titer (>100-fold). Enhanced cell-mediated IFNγ secreting influenza directed CD4+ and CD8+ T cell responses (>40-fold) to homotypic and heterosubtypic influenza A virus and peptides. Long-term and protective immunity was obtained. Conclusions: These results indicate that inactivated influenza virus that was formulated with N3 cationic adjuvant significantly enhanced broad systemic and mucosal influenza specific immune responses. These responses were broadened and further increased by incorporating DNA plasmids encoding FliC from S. typhimurum as an adjuvant providing long lasting protection against heterologous Influenza A/H1N1/CA09pdm virus challenge.

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Release of filamentous and spherical influenza A virus is not restricted by tetherin

Journal of General Virology ◽

10.1099/vir.0.038778-0 ◽

2012 ◽

Vol 93 (5) ◽

pp. 963-969 ◽

Cited By ~ 22

Author(s):

Emily A. Bruce ◽

Truus E. Abbink ◽

Helen M. Wise ◽

Ruth Rollason ◽

Rui Pedro Galao ◽

...

Keyword(s):

Plasma Membrane ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Infection ◽

Cellular Protein ◽

Spherical Particles ◽

Enveloped Viruses ◽

Specific Antagonist ◽

Multiple Strains ◽

Scanning Electron

The cellular protein tetherin is thought to act as a ‘leash’ that anchors many enveloped viruses to the plasma membrane and prevents their release. We found that replication of multiple strains of influenza A virus was generally insensitive to alteration of tetherin levels, as assessed by output titre or scanning electron microscopy of cell-associated virions. This included human, swine, avian and equine isolates, strains that form filamentous or spherical particles and viruses that lack the M2 or NS1 proteins. Levels of cell-surface tetherin were not reduced by influenza infection, but tetherin and the viral haemagglutinin co-localized on the plasma membrane. However, tetherin could not be detected in filamentous virions, suggesting that influenza may possess a mechanism to exclude it from virions. Overall, if influenza does encode a specific antagonist of tetherin, it is not M2 or NS1 and we find no evidence for a role in host range specificity.

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A screening pipeline identifies a broad-spectrum inhibitor of bacterial AB toxins with cross protection against influenza A virus H1N1 and SARS-CoV-2

10.1101/2021.08.13.454991 ◽

2021 ◽

Author(s):

Yu Wu ◽

Nassim Mahtal ◽

Lea Swistak ◽

Sara Sagadiev ◽

Mridu Acharya ◽

...

Keyword(s):

Influenza A Virus ◽

High Throughput Screening ◽

Influenza A ◽

Influenza Infection ◽

Chemical Compounds ◽

B Subunit ◽

Early Endosomes ◽

Cytotoxic Necrotizing Factor 1 ◽

Small Chemical

A challenge for the development of host-targeted anti-infectives against a large spectrum of AB-like toxin-producing bacteria encompasses the identification of chemical compounds corrupting toxin transport through both endolysosomal and retrograde pathways. Here, we performed a high-throughput screening of small chemical compounds blocking active Rac1 proteasomal degradation triggered by the Cytotoxic Necrotizing Factor-1 (CNF1) toxin, followed by orthogonal screens against two AB toxins hijacking defined endolysosomal (Diphtheria toxin) or retrograde (Shiga-like toxin 1) pathways to intoxicate cells. This led to the identification of the molecule N-(3,3-diphenylpropyl)-1-propyl-4-piperidinamine, referred to as C910. This compound induces the swelling of EEA1-positive early endosomes, in absence of PIKfyve kinase inhibition, and disturbs the trafficking of CNF1 and the B-subunit of Shiga toxin along the endolysosomal or retrograde pathways, respectively. Together, we show that C910 protects cells against 8 bacterial AB toxins including large clostridial glucosylating toxins from Clostridium difficile. Of interest, C910 also reduced viral infection in vitro including influenza A virus subtype H1N1 and SARS-CoV-2. Moreover, parenteral administration of C910 to the mice resulted in its accumulation in lung tissues and reduced lethal influenza infection.

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Features of immune response against influenza infection in animals vaccinated with recombinant cross-protective vaccine

Russian Journal of Infection and Immunity ◽

10.15789/2220-7619-2019-3-4-485-494 ◽

2019 ◽

Vol 9 (3-4) ◽

pp. 485-494

Author(s):

L. M. Tsybalova ◽

L. A. Stepanova ◽

A. V. Korotkov ◽

M. A. Shuklina ◽

M. V. Zaitseva ◽

...

Keyword(s):

Immune Response ◽

T Cells ◽

Influenza Virus ◽

Influenza A Virus ◽

Cd4 T Cells ◽

Influenza A ◽

Influenza Infection ◽

Sublethal Dose ◽

Universal Vaccine ◽

Toll Like Receptor 5

Generating cross-reactive vaccines aimed at targeting all human influenza A virus subtypes is among high priority tasks in contemporary vaccinology. Such vaccines will be primarily demanded during pre-pandemic period as well as used to prime some population cohorts prior to vaccination with standard vaccines containing area-relevant epidemic virus. Unlike routine approach universal vaccines do not induce a sterilizing immunity, but significantly ameliorate overt infection and probable complications. Our study was aimed at evaluating characteristics of immune response in experimental animals primed with a candidate universal vaccine challenged with sublethal influenza A virus infection. Mice were immunized intranasally with the recombinant protein FlgH2-2-4M2e containing conservative peptides derived from two influenza A virus proteins: M2 protein ectodomain and 76–130 amino acid sequence from the second hemagglutinin (HA2) subunit genetically linked to bacterial flagellin protein, which is a ligand for Toll-like receptor 5 (TLR5). Control mice received saline. Two weeks after immunization, mice from both groups were infected with a sublethal dose of A/Aichi/2/68 AN3N2 influenza virus strain. Level of immunoglobulins G and A in the blood sera and bronchoalveolar lavages (BAL) were determined two weeks after immunization and 1 month post infection. Percentage of lung CD4+ T and CD4+ Tem (CD44+CD62L–) cells secreting cytokines TNFα, IFNγ, IL-2 was determined. Immunized vs. control mice responded to sublethal infection with the influenza virus by insignificant weight loss and more pronounced production of vaccine peptide-specific (M2e and aa76–130 HA2) and pan-influenza A/Aichi/2/68 virus IgG and A in the blood sera and BAL. After challenge the number of CD4+ T cells secreting cytokines TNFα and/or IL-2 in immunized mice significantly exceeded counterpart T cells in unimmunized animals that was true for both CD4+T and CD4+ Tem cells. Memory CD4+ T cells were previously shown to play a key role in the prime-boost event and heterosubtypic immune response. Thus, we were able to demonstrate a priming effect for recombinant cross-protective vaccine used in our experiment.

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Profound Protection against Respiratory Challenge with a Lethal H7N7 Influenza A Virus by Increasing the Magnitude of CD8+ T-Cell Memory

Journal of Virology ◽

10.1128/jvi.74.24.11690-11696.2000 ◽

2000 ◽

Vol 74 (24) ◽

pp. 11690-11696 ◽

Cited By ~ 94

Author(s):

Jan P. Christensen ◽

Peter C. Doherty ◽

Kristen C. Branum ◽

Janice M. Riberdy

Keyword(s):

T Cells ◽

T Cell ◽

Influenza A Virus ◽

Influenza A ◽

Memory T Cells ◽

Influenza Infection ◽

T Cell Memory ◽

Influenza A Viruses ◽

Cell Memory ◽

Cell Pool

ABSTRACT The recall of CD8+ T-cell memory established by infecting H-2b mice with an H1N1 influenza A virus provided a measure of protection against an extremely virulent H7N7 virus. The numbers of CD8+ effector and memory T cells specific for the shared, immunodominant DbNP366epitope were greatly increased subsequent to the H7N7 challenge, and though lung titers remained as high as those in naive controls for 5 days or more, the virus was cleared more rapidly. Expanding the CD8+ memory T-cell pool (<0.5 to >10%) by sequential priming with two different influenza A viruses (H3N2→H1N1) gave much better protection. Though the H7N7 virus initially grew to equivalent titers in the lungs of naive and double-primed mice, the replicative phase was substantially controlled within 3 days. This tertiary H7N7 challenge caused little increase in the magnitude of the CD8+ DbNP366 + T-cell pool, and only a portion of the memory population in the lymphoid tissue could be shown to proliferate. The great majority of the CD8+ DbNP366 + set that localized to the infected respiratory tract had, however, cycled at least once, though recent cell division was shown not to be a prerequisite for T-cell extravasation. The selective induction of CD8+ T-cell memory can thus greatly limit the damage caused by a virulent influenza A virus, with the extent of protection being directly related to the number of available responders. Furthermore, a large pool of CD8+ memory T cells may be only partially utilized to deal with a potentially lethal influenza infection.

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Increased lethality in Influenza and SARS-CoV-2 co-infection is prevented by influenza immunity but not SARS-CoV-2 immunity

10.21203/rs.3.rs-136702/v1 ◽

2021 ◽

Author(s):

Hagit Achdout ◽

Einat B. Vitner ◽

Boaz Politi ◽

Sharon Melamed ◽

Yfat Yahalom-Ronen ◽

...

Keyword(s):

Viral Load ◽

Severe Acute Respiratory Syndrome ◽

Influenza A Virus ◽

Influenza A ◽

Influenza Infection ◽

Severe Disease ◽

Dual Infection ◽

Disease Outcome ◽

Severe Morbidity ◽

Experimental Support

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause for the ongoing COVID-19 pandemic1. The continued spread of SARS-CoV-2 along with the imminent flu season increase the probability of influenza-SARS-CoV-2 dual infection which might result in a severe disease. In this study, we examined the disease outcome of influenza A virus (IAV) and SARS-CoV-2 co-infection in K18-hACE2 mice. Our data indicates that IAV-infected mice are more susceptible to develop severe disease upon co-infection with SARS-CoV-2 two days post influenza infection. This co-infection results in severe morbidity and nearly uniform fatality as compared to the non-fatal influenza disease, or the partial fatality of SARS-CoV-2 alone. Co-infection was associated with elevated influenza viral load in respiratory organs. Remarkably, prior immunity to influenza, but not to SARS-CoV-2, prevented the severe disease and mortality. These data provide an experimental support that flu intervention by prior vaccination may be valuable in reducing the risk of sever Flu - SARS-CoV-2 comorbidity, and highlight the importance of vaccination.

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