Broad neutralization of H1 and H3 viruses by adjuvanted influenza HA stem vaccines in nonhuman primates

Seasonal influenza vaccines confer protection against specific viral strains but have restricted breadth that limits their protective efficacy. The H1 and H3 subtypes of influenza A virus cause most of the seasonal epidemics observed in humans and are the major drivers of influenza A virus–associated mortality. The consequences of pandemic spread of COVID-19 underscore the public health importance of prospective vaccine development. Here, we show that headless hemagglutinin (HA) stabilized-stem immunogens presented on ferritin nanoparticles elicit broadly neutralizing antibody (bnAb) responses to diverse H1 and H3 viruses in nonhuman primates (NHPs) when delivered with a squalene-based oil-in-water emulsion adjuvant, AF03. The neutralization potency and breadth of antibodies isolated from NHPs were comparable to human bnAbs and extended to mismatched heterosubtypic influenza viruses. Although NHPs lack the immunoglobulin germline VH1-69 residues associated with the most prevalent human stem-directed bnAbs, other gene families compensated to generate bnAbs. Isolation and structural analyses of vaccine-induced bnAbs revealed extensive interaction with the fusion peptide on the HA stem, which is essential for viral entry. Antibodies elicited by these headless HA stabilized-stem vaccines neutralized diverse H1 and H3 influenza viruses and shared a mode of recognition analogous to human bnAbs, suggesting that these vaccines have the potential to confer broadly protective immunity against diverse viruses responsible for seasonal and pandemic influenza infections in humans.

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Inactivation of avian influenza viruses by hydrostatic pressure as a potential vaccine development approach

Access Microbiology ◽

10.1099/acmi.0.000220 ◽

2021 ◽

Vol 3 (4) ◽

Author(s):

Shana Priscila Coutinho Barroso ◽

Ana Clara Vicente dos Santos ◽

Patrícia Souza dos Santos ◽

José Nelson dos Santos Silva Couceiro ◽

Davis Fernandes Ferreira ◽

...

Keyword(s):

Hydrostatic Pressure ◽

Avian Influenza ◽

Influenza A ◽

Vaccine Development ◽

Neutralizing Antibody ◽

Influenza Viruses ◽

Structure Morphology ◽

Potential Vaccine ◽

Development Approach ◽

H3n8 Virus

Vaccines are a recommended strategy for controlling influenza A infections in humans and animals. Here, we describe the effects of hydrostatic pressure on the structure, morphology and functional characteristics of avian influenza A H3N8 virus. The effect of hydrostatic pressure for 3 h on H3N8 virus revealed that the particles were resistant to this condition, and the virus displayed only a discrete conformational change. We found that pressure of 3 kbar applied for 6 h was able to inhibit haemagglutination and infectivity while virus replication was no longer observed, suggesting that full virus inactivation occurred at this point. However, the neuraminidase activity was not affected at this approach suggesting the maintenance of neutralizing antibody epitopes in this key antigen. Our data bring important information for the area of structural virology of enveloped particles and support the idea of applying pressure-induced inactivation as a tool for vaccine production.

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Design, synthesis and primary immunologic evaluation of M2e-CRM197 conjugate as a universal influenza vaccine candidate

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666201104145006 ◽

2020 ◽

Vol 21 ◽

Author(s):

Lu Xu ◽

Chun Zhang ◽

Jing Zhang ◽

Rong Yu ◽

Zhiguo Su

Keyword(s):

Immune Responses ◽

Influenza Vaccine ◽

Influenza A Virus ◽

Influenza A ◽

Vaccine Development ◽

Acute Infection ◽

Acid Hydrazide ◽

Influenza Viruses ◽

Carrier Protein ◽

Universal Influenza Vaccine

Background: Influenza is a contagious respiratory illness caused by acute infection of influenza viruses, among which influenza A virus causes epidemic seasonal infection nearly every year. Along with unpredictability of evolving influenza A virus and time-consuming vaccine development cycles, novel universal influenza vaccine designed to induce broadly cross-reactive immune responses against frequently mutant influenza A virus strains are greatly urgent. Objective: The aim of this study was to synthesize a novel vaccine through the dual-site specific conjugation of the constant epitope of 23 amino acids (M2e) of influenza A virus with highly immunogenic carrier protein of cross-reacting material (CRM197) under denaturation, and evaluate its primary immunogenicity in mice. Methods: The antigen (M2e) and the carrier protein (CRM197) were linked with different type of hetero-functionalized linkers, α-maleimide-ε-hydrazide polyethylene glycol 2k (MAL-PEG-HZ) and N-β-maleimidopropionic acid hydrazide (BMPH) separately. The immunogenicity of the M2e-CRM197 conjugates with different type of linkers was evaluated in mice, and the M2e-specific total IgG and IgG-isotypes were determined by ELSIA. Results: Immunogenicity study revealed that anti-M2e antibody could be induced by the conjugate products, M2e-PEGCRM197 and M2e-BMPH-CRM197, were approximately 30 and 90-fold higher than that of M2e group. In addition, the antiM2e antibody level induced by M2e-PEG-CRM197 conjugate was three times higher than that of M2e-BMPH-CRM197 conjugate, and the former could simultaneously activate both cellar and humoral immune responses. Conclusions: The M2e-CRM197 conjugated vaccines we synthesized in this study are highly immunogenic compared with M2e alone. Besides, evidences were presented here indicated that the hydrophilic, non-immunogenic and biocompatible chain of the cross-linker might be a better choice for development of conjugate vaccine.

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Protective Efficacy of Recombinant Influenza Hemagglutinin Ectodomain Fusions

Viruses ◽

10.3390/v13091710 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1710

Author(s):

Nidhi Mittal ◽

Nayanika Sengupta ◽

Sameer Kumar Malladi ◽

Poorvi Reddy ◽

Madhuraj Bhat ◽

...

Keyword(s):

Vaccine Efficacy ◽

Influenza A ◽

Protective Efficacy ◽

Neutralizing Antibody ◽

Surface Proteins ◽

Influenza Vaccines ◽

High Yield ◽

Suspension Cells ◽

Water Emulsion ◽

Antibody Titers

In current seasonal influenza vaccines, neutralizing antibody titers directed against the hemagglutinin surface protein are the primary correlate of protection. These vaccines are, therefore, quantitated in terms of their hemagglutinin content. Adding other influenza surface proteins, such as neuraminidase and M2e, to current quadrivalent influenza vaccines would likely enhance vaccine efficacy. However, this would come with increased manufacturing complexity and cost. To address this issue, as a proof of principle, we have designed genetic fusions of hemagglutinin ectodomains from H3 and H1 influenza A subtypes. These recombinant H1-H3 hemagglutinin ectodomain fusions could be transiently expressed at high yield in mammalian cell culture using Expi293F suspension cells. Fusions were trimeric, and as stable in solution as their individual trimeric counterparts. Furthermore, the H1-H3 fusion constructs were antigenically intact based on their reactivity with a set of conformation-specific monoclonal antibodies. H1-H3 hemagglutinin ectodomain fusion immunogens, when formulated with the MF59 equivalent adjuvant squalene-in-water emulsion (SWE), induced H1 and H3-specific humoral immune responses equivalent to those induced with an equimolar mixture of individually expressed H1 and H3 ectodomains. Mice immunized with these ectodomain fusions were protected against challenge with heterologous H1N1 (Bel/09) and H3N2 (X-31) mouse-adapted viruses with higher neutralizing antibody titers against the H1N1 virus. Use of such ectodomain-fused immunogens would reduce the number of components in a vaccine formulation and allow for the inclusion of other protective antigens to increase influenza vaccine efficacy.

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Viral Escape by Selection of Cytotoxic T Cell–Resistant Variants in Influenza a Virus Pneumonia

Journal of Experimental Medicine ◽

10.1084/jem.191.11.1853 ◽

2000 ◽

Vol 191 (11) ◽

pp. 1853-1868 ◽

Cited By ~ 73

Author(s):

Graeme E. Price ◽

Rong Ou ◽

Hong Jiang ◽

Lei Huang ◽

Demetrius Moskophidis

Keyword(s):

T Cell ◽

Influenza A Virus ◽

Influenza A ◽

Vaccine Development ◽

Acute Infection ◽

Influenza Viruses ◽

Viral Escape ◽

Cytotoxic T Cell ◽

Ctl Escape ◽

Selection Of

Antigenic variation is a strategy exploited by influenza viruses to promote survival in the face of the host adaptive immune response and constitutes a major obstacle to efficient vaccine development. Thus, variation in the surface glycoproteins hemagglutinin and neuraminidase is reflected by changes in susceptibility to antibody neutralization. This has led to the current view that antibody-mediated selection of influenza A viruses constitutes the basis for annual influenza epidemics and periodic pandemics. However, infection with this virus elicits a vigorous protective CD8+ cytotoxic T lymphocyte (CTL) response, suggesting that CD8+ CTLs might exert selection pressure on the virus. Studies with influenza A virus–infected transgenic mice bearing a T cell receptor (TCR) specific for viral nucleoprotein reveal that virus reemergence and persistence occurs weeks after the acute infection has apparently been controlled. The persisting virus is no longer recognized by CTLs, indicating that amino acid changes in the major viral nucleoprotein CTL epitope can be rapidly accumulated in vivo. These mutations lead to a total or partial loss of recognition by polyclonal CTLs by affecting presentation of viral peptide by class I major histocompatibility complex (MHC) molecules, or by interfering with TCR recognition of the mutant peptide–MHC complex. These data illustrate the distinct features of pulmonary immunity in selection of CTL escape variants. The likelihood of emergence and the biological impact of CTL escape variants on the clinical outcome of influenza pneumonia in an immunocompetent host, which is relevant for the design of preventive vaccines against this and other respiratory viral infections, are discussed.

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INDUCTION OF CROSS-REACTIVE ANTIBODIES IN MICE IMMUNIZED WITH CONSERVED LINEAR B-CELL EPITOPES DERIVED FROM INFLUENZA A VIRUS NEURAMINIDASE

Russian Journal of Infection and Immunity ◽

10.15789/10.15789/2220-7619-ioc-1343 ◽

2019 ◽

Author(s):

I Sychev ◽

P. Kopeikin ◽

E. Tsvetkova ◽

K. Cheredova ◽

B. Milman ◽

...

Keyword(s):

Weight Loss ◽

Influenza Virus ◽

B Cell ◽

Influenza A Virus ◽

Influenza A ◽

Protective Efficacy ◽

Influenza Viruses ◽

Influenza Vaccines ◽

B Cell Epitopes ◽

Linear B

Introduction. Influenza is a socially considerable infection annually causing profound damage to the populational health and economy. Vaccination is the most effective way to manage influenza and its complications. There are various vaccines against influenza, but their common drawback is the narrow specificity, need for annual virus strain renewal, not always good immunogenicity and effectiveness. In this regard, a close attention is paid to developing universal influenza vaccines aimed to induce cross-reactive factors of the immune response to the most conserved parts of viral proteins. Antibodies against neuraminidase (NA) are able to provide heterosubtypic protection, which is important due to potential threat from influenza viruses, with differed hemagglutinin and neuraminidase compared to the currently circulating viruses. The present study is aimed to search for new and analyze previously predicted linear NA B-cell epitopes, conserved among all subtypes of influenza A virus.Results. there were found out eight conserved linear B-cell epitopes were located around the neuraminidase active site, three of which (MNPNQKIITIGS, ILRTQESEC, and DNWKGSNRP) were synthesized de novo, conjugated with bovine serum albumin to be further used for mouse immunization. Serum IgG antibodies were detected by ELISA in immunized mice. Antibodies specifically bind to various influenza A viruses containing NA subtypes N1, N2, N3, and N9. Immunization with NA peptides provided no protection from profound weight loss after infection with lethal H1N1 influenza virus. However, all immunized mice survived during the observation period, while in control group survival rate was as low as 28.6%. Assessing the viral load in the lungs of mice infected with the H1N1 virus did not reveal differences in titers either on day 4 or 8 post-infection. Nevertheless, the protective effect lacked upon challenge with lethal H7N9 influenza virus: mortality, weight loss, and lung virus titers were comparable both in immunized and control mice.Conclusions. The data obtained uncovered cross-reactivity in anti-NA antibodies induced by immunization with NA peptides as well as protective efficacy against infection caused by the H1N1, but not H7N9 virus. Thus, these data are promising and indicate that linear B-cell NA epitopes can be used for design of epitope-directed influenza vaccines, but a deeper and full examination of specificity for conserved NA epitopes as well as optimized immunization schemes are necessary to achieve higher protective efficacy.

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Thapsigargin Is a Broad-Spectrum Inhibitor of Major Human Respiratory Viruses: Coronavirus, Respiratory Syncytial Virus and Influenza A Virus

Viruses ◽

10.3390/v13020234 ◽

2021 ◽

Vol 13 (2) ◽

pp. 234

Author(s):

Sarah Al-Beltagi ◽

Cristian Alexandru Preda ◽

Leah V. Goulding ◽

Joe James ◽

Juan Pu ◽

...

Keyword(s):

Influenza Virus ◽

Respiratory Syncytial Virus ◽

Influenza A Virus ◽

Broad Spectrum ◽

Influenza A ◽

Respiratory Viruses ◽

Influenza Viruses ◽

Virus Challenge ◽

2009 H1n1 ◽

Syncytial Virus

The long-term control strategy of SARS-CoV-2 and other major respiratory viruses needs to include antivirals to treat acute infections, in addition to the judicious use of effective vaccines. Whilst COVID-19 vaccines are being rolled out for mass vaccination, the modest number of antivirals in use or development for any disease bears testament to the challenges of antiviral development. We recently showed that non-cytotoxic levels of thapsigargin (TG), an inhibitor of the sarcoplasmic/endoplasmic reticulum (ER) Ca2+ ATPase pump, induces a potent host innate immune antiviral response that blocks influenza A virus replication. Here we show that TG is also highly effective in blocking the replication of respiratory syncytial virus (RSV), common cold coronavirus OC43, SARS-CoV-2 and influenza A virus in immortalized or primary human cells. TG’s antiviral performance was significantly better than remdesivir and ribavirin in their respective inhibition of OC43 and RSV. Notably, TG was just as inhibitory to coronaviruses (OC43 and SARS-CoV-2) and influenza viruses (USSR H1N1 and pdm 2009 H1N1) in separate infections as in co-infections. Post-infection oral gavage of acid-stable TG protected mice against a lethal influenza virus challenge. Together with its ability to inhibit the different viruses before or during active infection, and with an antiviral duration of at least 48 h post-TG exposure, we propose that TG (or its derivatives) is a promising broad-spectrum inhibitor against SARS-CoV-2, OC43, RSV and influenza virus.

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Functional Analysis of PA Binding by Influenza A Virus PB1: Effects on Polymerase Activity and Viral Infectivity

Journal of Virology ◽

10.1128/jvi.75.17.8127-8136.2001 ◽

2001 ◽

Vol 75 (17) ◽

pp. 8127-8136 ◽

Cited By ~ 78

Author(s):

Daniel R. Perez ◽

Ruben O. Donis

Keyword(s):

Amino Acids ◽

Influenza Virus ◽

Amino Acid ◽

Viral Replication ◽

Influenza A Virus ◽

Influenza A ◽

Amino Acid Sequences ◽

Influenza Viruses ◽

Virus Growth ◽

Transcription And Replication

ABSTRACT Influenza A virus expresses three viral polymerase (P) subunits—PB1, PB2, and PA—all of which are essential for RNA and viral replication. The functions of P proteins in transcription and replication have been partially elucidated, yet some of these functions seem to be dependent on the formation of a heterotrimer for optimal viral RNA transcription and replication. Although it is conceivable that heterotrimer subunit interactions may allow a more efficient catalysis, direct evidence of their essentiality for viral replication is lacking. Biochemical studies addressing the molecular anatomy of the P complexes have revealed direct interactions between PB1 and PB2 as well as between PB1 and PA. Previous studies have shown that the N-terminal 48 amino acids of PB1, termed domain α, contain the residues required for binding PA. We report here the refined mapping of the amino acid sequences within this small region of PB1 that are indispensable for binding PA by deletion mutagenesis of PB1 in a two-hybrid assay. Subsequently, we used site-directed mutagenesis to identify the critical amino acid residues of PB1 for interaction with PA in vivo. The first 12 amino acids of PB1 were found to constitute the core of the interaction interface, thus narrowing the previous boundaries of domain α. The role of the minimal PB1 domain α in influenza virus gene expression and genome replication was subsequently analyzed by evaluating the activity of a set of PB1 mutants in a model reporter minigenome system. A strong correlation was observed between a functional PA binding site on PB1 and P activity. Influenza viruses bearing mutant PB1 genes were recovered using a plasmid-based influenza virus reverse genetics system. Interestingly, mutations that rendered PB1 unable to bind PA were either nonviable or severely growth impaired. These data are consistent with an essential role for the N terminus of PB1 in binding PA, P activity, and virus growth.

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Protective Efficacy and Immunogenicity of a Combinatory DNA Vaccine against Influenza A Virus and the Respiratory Syncytial Virus

PLoS ONE ◽

10.1371/journal.pone.0072217 ◽

2013 ◽

Vol 8 (8) ◽

pp. e72217 ◽

Cited By ~ 16

Author(s):

Viktoria Stab ◽

Sandra Nitsche ◽

Thomas Niezold ◽

Michael Storcksdieck genannt Bonsmann ◽

Andrea Wiechers ◽

...

Keyword(s):

Respiratory Syncytial Virus ◽

Influenza A Virus ◽

Dna Vaccine ◽

Influenza A ◽

Protective Efficacy ◽

Syncytial Virus

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Clinical Investigations. Comparison of Directigen Flu A+B with Real Time PCR in the Diagnosis of Influenza / Сравнение Иммунохроматографического Метода (Directigen Flu A+B) И Теста RT-PCR При Инфекциях Гриппа

Folia Medica ◽

10.1515/folmed-2015-0027 ◽

2015 ◽

Vol 57 (2) ◽

pp. 104-110 ◽

Cited By ~ 4

Author(s):

Golubinka Bosevska ◽

Nikola Panovski ◽

Elizabeta Janceska ◽

Vladimir Mikik ◽

Irena Kondova Topuzovska ◽

...

Keyword(s):

Real Time ◽

Influenza A Virus ◽

Real Time Pcr ◽

Influenza A ◽

Age Groups ◽

Influenza Viruses ◽

Influenza B Virus ◽

Influenza B ◽

B Virus ◽

Nose And Throat

AbstractEarly diagnosis and treatment of patients with influenza is the reason why physicians need rapid high-sensitivity influenza diagnostic tests that require no complex lab equipment and can be performed and interpreted within 15 min. The Aim of this study was to compare the rapid Directigen Flu A+B test with real time PCR for detection of influenza viruses in the Republic of Macedonia. MATERIALS AND METHODS: One-hundred-eight respiratory samples (combined nose and throat swabs) were routinely collected for detection of influenza virus during influenza seasons. Forty-one patients were pediatric cases and 59 were adult. Their mean age was 23 years. The patients were allocated into 6 age groups: 0 - 4 yrs, 5 - 9 yrs, 10 - 14 yrs, 15 - 19 yrs, 20-64 yrs and > 65 yrs. Each sample was tested with Directigen Flu A+B and CDC real time PCR kit for detection and typisation/subtypisation of influenza according to the lab diagnostic protocol. RESULTS: Directigen Flu A+B identified influenza A virus in 20 (18.5%) samples and influenza B virus in two 2 (1.9%) samples. The high specificity (100%) and PPV of Directigen Flu A+B we found in our study shows that the positive results do not need to be confirmed. The overall sensitivity of Directigen Flu A+B is 35.1% for influenza A virus and 33.0% for influenza B virus. The sensitivity for influenza A is higher among children hospitalized (45.0%) and outpatients (40.0%) versus adults. CONCLUSION: Directigen Flu A+B has relatively low sensitivity for detection of influenza viruses in combined nose and throat swabs. Negative results must be confirmed.

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Dynamic interactions of influenza viruses in Hong Kong during 1998-2018

10.1101/19008987 ◽

2019 ◽

Cited By ~ 1

Author(s):

Wan Yang ◽

Eric H. Y. Lau ◽

Benjamin J. Cowling

Keyword(s):

Hong Kong ◽

Influenza A ◽

Vaccine Development ◽

Immune Escape ◽

Influenza Viruses ◽

Influenza Surveillance ◽

Influenza Epidemic ◽

Inference System ◽

Population Immunity ◽

Cross Immunity

AbstractInfluenza epidemics cause substantial morbidity and mortality every year worldwide. Currently, two influenza A subtypes, A(H1N1) and A(H3N2), and type B viruses co-circulate in humans and infection with one type/subtype could provide cross-protection against the others. However, it remains unclear how such ecologic competition via cross-immunity and antigenic mutations that allow immune escape impact influenza epidemic dynamics at the population level. Here we develop a comprehensive model-inference system and apply it to study the evolutionary and epidemiological dynamics of the three influenza types/subtypes in Hong Kong, a city of global public health significance for influenza epidemic and pandemic control. Utilizing long-term influenza surveillance data since 1998, we are able to estimate the strength of cross-immunity between each virus-pairs, the timing and frequency of punctuated changes in population immunity in response to antigenic mutations in influenza viruses, and key epidemiological parameters over the last 20 years including the 2009 pandemic. We find evidence of cross-immunity in all types/subtypes, with strongest cross-immunity from A(H1N1) against A(H3N2). Our results also suggest that A(H3N2) may undergo antigenic mutations in both summers and winters and thus monitoring the virus in both seasons may be important for vaccine development. Overall, our study reveals intricate epidemiological interactions and underscores the importance of simultaneous monitoring of population immunity, incidence rates, and viral genetic and antigenic changes.

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