#Mucosal #Immunity against #Neuraminidase Prevents #Influenza B Virus #Transmission in Guinea Pigs (mBio, abstract)

[Source: mBio, full page: (LINK). Abstract, edited.]

Mucosal Immunity against Neuraminidase Prevents Influenza B Virus Transmission in Guinea Pigs

Meagan McMahon, Ericka Kirkpatrick, Daniel Stadlbauer, Shirin Strohmeier, Nicole M. Bouvier, Florian Krammer

Stacey Schultz-Cherry, Editor

DOI: 10.1128/mBio.00560-19



Despite efforts to control influenza virus infection and transmission, influenza viruses still cause significant morbidity and mortality in the global human population each year. Most of the current vaccines target the immunodominant hemagglutinin surface glycoprotein of the virus. However, reduced severity of disease and viral shedding have also been linked to antibodies targeting the second viral surface glycoprotein, the neuraminidase. Importantly, antineuraminidase immunity was shown to be relatively broad, in contrast to vaccine-induced antibodies to the hemagglutinin head domain. In this study, we assessed recombinant neuraminidase protein vaccination for its ability to prevent or limit virus transmission. We vaccinated guinea pigs either intramuscularly or intranasally with a recombinant influenza B virus neuraminidase to assess whether neuraminidase vaccination via these routes could prevent transmission of the homologous virus to a naive recipient. Guinea pigs vaccinated with neuraminidase showed reduced virus titers; however, only vaccination via the intranasal route fully prevented virus transmission to naive animals. We found high levels of antineuraminidase antibodies capable of inhibiting neuraminidase enzymatic activity in the nasal washes of intranasally vaccinated animals, which may explain the observed differences in transmission. We also determined that mucosal immunity to neuraminidase impaired the transmission efficiency of a heterologous influenza B virus, although to a lesser extent. Finally, we found that neuraminidase-vaccinated animals were still susceptible to infection via the airborne and contact transmission routes. However, significantly lower virus titers were detected in these vaccinated recipients. In summary, our data suggest that supplementing vaccine formulations with neuraminidase and vaccinating via the intranasal route may broadly prevent transmission of influenza B viruses.



Recently, the protective effect of anti-neuraminidase immunity has been highlighted by several studies in humans and animal models. However, so far the role that anti-neuraminidase immunity plays in inhibition of virus transmission has not been explored. In addition, neuraminidase has been ignored as an antigen for influenza virus vaccines. We show here that neuraminidase-based vaccines can inhibit the transmission of influenza virus. Therefore, neuraminidase should be considered as an antigen for improved influenza virus vaccines that not only protect individuals from disease but also inhibit further spread of the virus in the population.

Keywords: Seasonal Influenza; Influenza B; Vaccines; Animal models.



In vitro #neuraminidase inhibitory concentration (#IC50) of four neuraminidase inhibitors in the #Japanese 2017-18 #season: Comparison with the 2010-11 to 2016-17 seasons (J Infect Chemother., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

J Infect Chemother. 2019 May 14. pii: S1341-321X(19)30099-6. doi: 10.1016/j.jiac.2019.04.007. [Epub ahead of print]

In vitro neuraminidase inhibitory concentration (IC50) of four neuraminidase inhibitors in the Japanese 2017-18 season: Comparison with the 2010-11 to 2016-17 seasons.

Ikematsu H1, Kawai N2, Chong Y3, Bando T2, Iwaki N2, Kashiwagi S2.

Author information: 1 Japan Physicians Association, Tokyo, Japan; Ricerca Clinica Co., Fukuoka, Japan. Electronic address: ikematsu@gray.plala.or.jp. 2 Japan Physicians Association, Tokyo, Japan. 3 Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.



To assess the extent of susceptibility to the four most commonly used neuraminidase inhibitors (NAIs) of the viruses epidemic in the 2017-18 Japanese influenza season, we measured the 50% inhibitory concentration (IC50) for influenza virus isolates from patients and compared them with the results from the 2010-11 to 2016-17 seasons. Viral isolation was done with specimens obtained prior to treatment, and the type and subtype was determined by RT-PCR using type- and subtype-specific primers. The IC50 was determined by a neuraminidase inhibition assay using a fluorescent substrate. A total of 237 virus isolates, 50 A(H1N1)pdm09, 92 A(H3N2), and 95 B were measured. No A(H1N1)pdm09 with highly reduced sensitivity for oseltamivir was found in the 2017-18 season. No isolates with highly reduced sensitivity to the four NAIs have been found for A(H3N2) or B from the 2010-11 to 2017-18 seasons. The geometric mean IC50s of the four NAIs were quite consistent during the eight studied seasons. These results indicate that the sensitivity to the four commonly used NAIs has been maintained.

Copyright © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

KEYWORDS: 50% inhibitory concentration; Influenza virus; Neuraminidase inhibitor; Resistance; Surveillance

PMID: 31101530 DOI: 10.1016/j.jiac.2019.04.007

Keywords: Antivirals; Drugs Resistance; Oseltamivir; Zanamivir; Peramivir; Laninamivir; Japan; Seasonal Influenza; H1N1pdm09; H3N2; Influenza B.


#Dual and #triple #infections with #Influenza A and B viruses: a case-control study in Southern #Brazil (J Infect Dis., abstract)

[Source: Journal of Infectious Diseases, full page: (LINK). Abstract, edited.]

Dual and triple infections with Influenza A and B viruses: a case-control study in Southern Brazil

Tatiana Schäffer Gregianini, Ivana R Santos Varella, Patricia Fisch, Letícia Garay Martins, Ana B G Veiga

The Journal of Infectious Diseases, jiz221, https://doi.org/10.1093/infdis/jiz221

Published: 29 April 2019



Influenza surveillance is important for disease control and should consider possible coinfection with different viruses, which can be associated with disease severity. This study analyzed 34,459 patients with respiratory infection from 2009 to 2018, of which 8,011 were positive for IAV or IBV. We found 18 cases of influenza dual infection, including H1N1pdm09 and H3N2 (1 case), H1N1pdm09 and IBV (6 cases), H3N2 and IBV (8 cases), and non-subtyped IAV and IBV (3 cases); and one case of triple detection of H3N2, H1N1pdm09 and IBV. Compared with mono-infected patients (n=76), coinfection was significantly associated with cardiopathy and death. Besides demographics and clinical symptoms, we assessed vaccination status, antiviral treatment, time of antiviral use, hospitalization, and ICU admission, but no significant differences were found between coinfected or mono-infected cases. Our findings indicate that influenza coinfection occurs more often than previously reported and that it can lead to a worse disease outcome.

Influenza Virus, Coinfection, Respiratory Infections

Topic: influenza – heart diseases – antiviral agents – brazil – demography – herpesvirus 1, cercopithecine – infectious mononucleosis – intensive care unit – orthomyxoviridae – respiratory tract infections – vaccination – infection – influenzavirus a – viruses – coinfection – surveillance, medical – influenza a virus, h3n2 subtype – severity of illness

Issue Section: Major Article

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© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)

Keywords: Seasonal Influenza; H1N1pdm09; H3N2; Influenza B; Brazil.


Development of #Influenza B #Universal #Vaccine Candidates using the “#Mosaic” #Hemagglutinin Approach (J Virol., abstract)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Development of Influenza B Universal Vaccine Candidates using the “Mosaic” Hemagglutinin Approach

Weina Sun, Ericka Kirkpatrick, Megan Ermler, Raffael Nachbagauer, Felix Broecker, Florian Krammer, Peter Palese

DOI: 10.1128/JVI.00333-19



Influenza B viruses cause seasonal epidemics and are a considerable burden to public health. However, protection by current seasonal vaccines is suboptimal due to the antigenic changes of the circulating strains. In this study, we report a novel universal influenza B virus vaccination strategy based on mosaic hemagglutinins. We generated mosaic B hemagglutinins by replacing the major antigenic sites of the type B hemagglutinin with corresponding sequences from exotic influenza A hemagglutinins and expressed them as soluble trimeric proteins. Sequential vaccination with recombinant mosaic B hemagglutinin proteins conferred cross-protection against both homologous and heterologous influenza B virus strains in the mouse model. Of note, we rescued recombinant influenza B viruses expressing mosaic B hemagglutinins, which could serve as the basis for a universal influenza B virus vaccine.



This work reports a universal influenza B virus vaccination strategy based on focusing antibody responses to conserved head and stalk epitopes of the hemagglutinin. Recombinant mosaic influenza B hemagglutinin proteins and recombinant viruses have been generated as novel vaccine candidates. This vaccine strategy provided broad cross-protection in the mouse model. Our findings will inform and drive the development toward a more effective influenza B virus vaccine.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Seasonal Influenza; Influenza B; Vaccines.


#Sequencing #framework for the sensitive detection and precise mapping of defective interfering particle-associated deletions across #influenza A and B viruses (J Virol., abstrac t)

[Source: Journal of Virology, full page: (LINK). Abstract, edited.]

Sequencing framework for the sensitive detection and precise mapping of defective interfering particle-associated deletions across influenza A and B viruses.

Fadi G. Alnaji, Jessica R. Holmes, Gloria Rendon, J. Cristobal Vera, Chris Fields, Brigitte E. Martin, Christopher B. Brooke

DOI: 10.1128/JVI.00354-19



The mechanisms and consequences of defective interfering particle (DIP) formation during influenza virus infection remain poorly understood. The development of next generation sequencing (NGS) technologies has made it possible to identify large numbers of DIP-associated sequences, providing a powerful tool to better understand their biological relevance. However, NGS approaches pose numerous technical challenges including the precise identification and mapping of deletion junctions in the presence of frequent mutation and base-calling errors, and the potential for numerous experimental and computational artifacts. Here we detail an Illumina-based sequencing framework and bioinformatics pipeline capable of generating highly accurate and reproducible profiles of DIP-associated junction sequences. We use a combination of simulated and experimental control datasets to optimize pipeline performance and demonstrate the absence of significant artifacts. Finally, we use this optimized pipeline to reveal how the patterns of DIP-associated junction formation differ between different strains and subtypes of influenza A and B viruses and to demonstrate how this data can provide insight into mechanisms of DIP formation. Overall, this work provides a detailed roadmap for high resolution profiling and analysis of DIP-associated sequences within influenza virus populations.



Influenza virus defective interfering particles (DIPs) that harbor internal deletions within their genomes occur naturally during infection in humans and cell culture. They have been hypothesized to influence the pathogenicity of the virus; however, their specific function remains elusive. The accurate detection of DIP-associated deletion junctions is crucial for understanding DIP biology but is complicated by an array of technical issue that can bias or confound results. Here we demonstrate a combined experimental and computational framework for detecting DIP-associated deletion junctions using next generation sequencing (NGS). We detail how to validate pipeline performance and provide the bioinformatics pipeline for groups interested in using it. Using this optimized pipeline, we detect hundreds of distinct deletion junctions generated during infection with a diverse panel of influenza viruses and use these data to test a long-standing hypothesis concerning the molecular details of DIP formation.

Copyright © 2019 American Society for Microbiology. All Rights Reserved.

Keywords: Influenza A; Influenza B; Genetics.


Broad and Protective #Influenza B Virus #Neuraminidase #Antibodies in #Humans after #Vaccination and their Clonal Persistence as Plasma Cells (mBio, abstract)

[Source: mBio, full page: (LINK). Abstract, edited.]

Broad and Protective Influenza B Virus Neuraminidase Antibodies in Humans after Vaccination and their Clonal Persistence as Plasma Cells

Michael S. Piepenbrink, Aitor Nogales, Madhubanti Basu, Christopher F. Fucile, Jane L. Liesveld, Michael C. Keefer, Alexander F. Rosenberg, Luis Martinez-Sobrido, James J. Kobie

Anne Moscona, Editor

DOI: 10.1128/mBio.00066-19



Although most seasonal inactivated influenza vaccines (IIV) contain neuraminidase (NA), the extent and mechanisms of action of protective human NA-specific humoral responses induced by vaccination are poorly resolved. Due to the propensity of influenza virus for antigenic drift and shift and its tendency to elicit predominantly strain-specific antibodies, humanity remains susceptible to waves of new strains of seasonal viruses and is at risk from viruses with pandemic potential for which limited or no immunity may exist. Here we demonstrate that the use of IIV results in increased levels of influenza B virus (IBV) NA-specific serum antibodies. Detailed analysis of the IBV NA B cell response indicates concurrent expansion of IBV NA-specific peripheral blood plasmablasts 7 days after IIV immunization which express monoclonal antibodies with broad and potent antiviral activity against both IBV Victoria and Yamagata lineages and prophylactic and therapeutic activity in mice. These IBV NA-specific B cell clonal lineages persisted in CD138+ long-lived bone marrow plasma cells. These results represent the first demonstration that IIV-induced NA human antibodies can protect and treat influenza virus infection in vivo and suggest that IIV can induce a subset of IBV NA-specific B cells with broad protective potential, a feature that warrants further study for universal influenza vaccine development.



Influenza virus infections continue to cause substantial morbidity and mortality despite the availability of seasonal vaccines. The extensive genetic variability in seasonal and potentially pandemic influenza strains necessitates new vaccine strategies that can induce universal protection by focusing the immune response on generating protective antibodies against conserved targets such as regions within the influenza neuraminidase protein. We have demonstrated that seasonal immunization stimulates neuraminidase-specific antibodies in humans that are broad and potent in their protection from influenza B virus when tested in mice. These antibodies further persist in the bone marrow, where they are expressed by long-lived antibody-producing cells, referred to here as plasma cells. The significance in our research is the demonstration that seasonal influenza immunization can induce a subset of neuraminidase-specific B cells with broad protective potential, a process that if further studied and enhanced could aid in the development of a universal influenza vaccine.

Keywords: Seasonal Influenza; Influenza B; Vaccines.


Reduced Susceptibility to #Neuraminidase #Inhibitors in #Influenza B Isolate, #Canada (Emerg Infect Dis., abstract)

[Source: US Centers for Disease Control and Prevention (CDC), Emerging Infectious Diseases Journal, full page: (LINK). Abstract, edited.]

Volume 25, Number 4—April 2019 / Research Letter

Reduced Susceptibility to Neuraminidase Inhibitors in Influenza B Isolate, Canada

Yacine Abed1, Clément Fage1, Patrick Lagüe, Julie Carbonneau, Jesse Papenburg, Donald C. Vinh, and Guy Boivin

Author affiliations: Laval University, Québec City, Québec, Canada (Y. Abed, C. Fage, P. Lagüe, J. Carbonneau, G. Boivin); Montreal Children’s Hospital, Montreal, Québec (J. Papenburg); McGill University Health Center, Montreal (D.C. Vinh)



We identified an influenza B isolate harboring a Gly407Ser neuraminidase substitution in an immunocompromised patient in Canada before antiviral therapy. This mutation mediated reduced susceptibility to oseltamivir, zanamivir, and peramivir, most likely by preventing interaction with the catalytic Arg374 residue. The potential emergence of such variants emphasizes the need for new antivirals.

Keywords: Seasonal Influenza; Influenza B; Antivirals; Drugs Resistance; Oseltamivir; Zanamivir; Peramivir; Canada.