Intranasal powder live attenuated influenza vaccine is thermostable, immunogenic, and protective against homologous challenge in ferrets

AbstractInfluenza viruses cause annual seasonal epidemics and sporadic pandemics; vaccination is the most effective countermeasure. Intranasal live attenuated influenza vaccines (LAIVs) are needle-free, mimic the natural route of infection, and elicit robust immunity. However, some LAIVs require reconstitution and cold-chain requirements restrict storage and distribution of all influenza vaccines. We generated a dry-powder, thermostable LAIV (T-LAIV) using Preservation by Vaporization technology and assessed the stability, immunogenicity, and efficacy of T-LAIV alone or combined with delta inulin adjuvant (Advax™) in ferrets. Stability assays demonstrated minimal loss of T-LAIV titer when stored at 25 °C for 1 year. Vaccination of ferrets with T-LAIV alone or with delta inulin adjuvant elicited mucosal antibody and robust serum HI responses in ferrets, and was protective against homologous challenge. These results suggest that the Preservation by Vaporization-generated dry-powder vaccines could be distributed without refrigeration and administered without reconstitution or injection. Given these significant advantages for vaccine distribution and delivery, further research is warranted.

Download Full-text

Viral Subpopulation Screening Guides in Designing a High Interferon-Inducing Live Attenuated Influenza Vaccine by Targeting Rare Mutations in NS1 and PB2 Proteins

Journal of Virology ◽

10.1128/jvi.01722-20 ◽

2020 ◽

Vol 95 (2) ◽

pp. e01722-20

Author(s):

Amir Ghorbani ◽

Michael C. Abundo ◽

Hana Ji ◽

Kara J. M. Taylor ◽

John M. Ngunjiri ◽

...

Keyword(s):

Cell Culture ◽

Influenza Vaccine ◽

Influenza Viruses ◽

Translation Initiation Factor ◽

Influenza Vaccines ◽

Effective Control ◽

Live Vaccines ◽

Live Attenuated Influenza Vaccine ◽

Nonstructural Protein 1 ◽

Interferon Responses

ABSTRACTInfluenza A viruses continue to circulate among wild birds and poultry worldwide, posing constant pandemic threats to humans. Effective control of emerging influenza viruses requires new broadly protective vaccines. Live attenuated influenza vaccines with truncations in nonstructural protein 1 (NS1) have shown broad protective efficacies in birds and mammals, which correlate with the ability to induce elevated interferon responses in the vaccinated hosts. Given the extreme diversity of influenza virus populations, we asked if we could improve an NS1-truncated live attenuated influenza vaccine developed for poultry (PC4) by selecting viral subpopulations with enhanced interferon-inducing capacities. Here, we deconstructed a de novo population of PC4 through plaque isolation, created a large library of clones, and assessed their interferon-inducing phenotypes. While most of the clones displayed the parental interferon-inducing phenotype in cell culture, few clones showed enhanced interferon-inducing phenotypes in cell culture and chickens. The enhanced interferon-inducing phenotypes were linked to either a deletion in NS1 (NS1Δ76-86) or a substitution in polymerase basic 2 protein (PB2-D309N). The NS1Δ76-86 deletion disrupted the putative eukaryotic translation initiation factor 4GI-binding domain and promoted the synthesis of biologically active interferons. The PB2-D309N substitution enhanced the early transcription of interferon mRNA, revealing a novel role for the 309D residue in suppression of interferon responses. We combined these mutations to engineer a novel vaccine candidate that induced additive amounts of interferons and stimulated protective immunity in chickens. Therefore, viral subpopulation screening approaches can guide the design of live vaccines with strong immunostimulatory properties.IMPORTANCE Effectiveness of NS1-truncated live attenuated influenza vaccines relies heavily on their ability to induce elevated interferon responses in vaccinated hosts. Influenza viruses contain diverse particle subpopulations with distinct phenotypes. We show that live influenza vaccines can contain underappreciated subpopulations with enhanced interferon-inducing phenotypes. The genomic traits of such virus subpopulations can be used to further improve the efficacy of the current live vaccines.

Download Full-text

A Live Attenuated Influenza Vaccine Elicits Enhanced Heterologous Protection When the Internal Genes of the Vaccine Are Matched to Those of the Challenge Virus

Journal of Virology ◽

10.1128/jvi.01065-19 ◽

2019 ◽

Vol 94 (4) ◽

Cited By ~ 3

Author(s):

Andrew Smith ◽

Laura Rodriguez ◽

Maya El Ghouayel ◽

Aitor Nogales ◽

Jeffrey M. Chamberlain ◽

...

Keyword(s):

Influenza Vaccine ◽

Influenza A ◽

H1n1 Virus ◽

Influenza Infection ◽

Influenza Viruses ◽

Influenza Vaccines ◽

Temperature Sensitive ◽

Live Attenuated Influenza Vaccine ◽

Cell Immunity

ABSTRACT Influenza A virus (IAV) causes significant morbidity and mortality, despite the availability of viral vaccines. The efficacy of live attenuated influenza vaccines (LAIVs) has been especially poor in recent years. One potential reason is that the master donor virus (MDV), on which all LAIVs are based, contains either the internal genes of the 1960 A/Ann Arbor/6/60 or the 1957 A/Leningrad/17/57 H2N2 viruses (i.e., they diverge considerably from currently circulating strains). We previously showed that introduction of the temperature-sensitive (ts) residue signature of the AA/60 MDV into a 2009 pandemic A/California/04/09 H1N1 virus (Cal/09) results in only 10-fold in vivo attenuation in mice. We have previously shown that the ts residue signature of the Russian A/Leningrad/17/57 H2N2 LAIV (Len LAIV) more robustly attenuates the prototypical A/Puerto Rico/8/1934 (PR8) H1N1 virus. In this work, we therefore introduced the ts signature from Len LAIV into Cal/09. This new Cal/09 LAIV is ts in vitro, highly attenuated (att) in mice, and protects from a lethal homologous challenge. In addition, when our Cal/09 LAIV with PR8 hemagglutinin and neuraminidase was used to vaccinate mice, it provided enhanced protection against a wild-type Cal/09 challenge relative to a PR8 LAIV with the same attenuating mutations. These findings suggest it may be possible to improve the efficacy of LAIVs by better matching the sequence of the MDV to currently circulating strains. IMPORTANCE Seasonal influenza infection remains a major cause of disease and death, underscoring the need for improved vaccines. Among current influenza vaccines, the live attenuated influenza vaccine (LAIV) is unique in its ability to elicit T-cell immunity to the conserved internal proteins of the virus. Despite this, LAIV has shown limited efficacy in recent years. One possible reason is that the conserved, internal genes of all current LAIVs derive from virus strains that were isolated between 1957 and 1960 and that, as a result, do not resemble currently circulating influenza viruses. We have therefore developed and tested a new LAIV, based on a currently circulating pandemic strain of influenza. Our results show that this new LAIV elicits improved protective immunity compared to a more conventional LAIV.

Download Full-text

Viral evolutionary dynamics predict Influenza-Like-Illnesses in patients

10.1101/2021.01.31.429026 ◽

2021 ◽

Author(s):

Christopher D. Wallbank ◽

Stéphane Aris-Brosou

Keyword(s):

Predictive Power ◽

Evolutionary Dynamics ◽

Viral Infections ◽

Influenza Viruses ◽

Evolutionary Analysis ◽

Health Authorities ◽

Show Evidence ◽

Influenza Activity ◽

Seasonal Epidemics ◽

The Stability

AbstractViral infections such as those caused by the influenza virus can put a strain on healthcare systems. However, such a burden is typically difficult to predict. In order to improve such predictions, we hypothesize that the severity of epidemics can be linked to viral evolutionary dynamics. More specifically, we posit the existence of a negative association between patients’ health and the stability of coevolutionary networks at key viral proteins. To test this, we performed a thorough evolutionary analysis of influenza viruses circulating in continental US between 2010 and 2019, assessing how measures of the stability of these coevolutionary networks correlate with clinical data based on outpatient healthcare visits showing Influenza-Like Illness (ILI) symptoms. We first show evidence of a significant correlation between viral evolutionary dynamics and increased influenza activity during seasonal epidemics, and then show that these dynamics closely follow the progression of epidemics through each season, providing us with predictive power based on genetic data collected between week 20 and week 40/52, that is one to fifteen weeks prior to peak ILI. Viral evolutionary dynamics may hence be used by health authorities to further guide non-pharmaceutical interventions.

Download Full-text

Novel Approaches for The Development of Live Attenuated Influenza Vaccines

Viruses ◽

10.3390/v11020190 ◽

2019 ◽

Vol 11 (2) ◽

pp. 190 ◽

Cited By ~ 17

Author(s):

Pilar Blanco-Lobo ◽

Aitor Nogales ◽

Laura Rodríguez ◽

Luis Martínez-Sobrido

Keyword(s):

Influenza A ◽

Reverse Genetics ◽

Seasonal Influenza ◽

Influenza Viruses ◽

Antigenic Drift ◽

Influenza Vaccines ◽

Global Public Health ◽

Protection Efficacy ◽

Seasonal Epidemics ◽

Rapid Generation

Influenza virus still represents a considerable threat to global public health, despite the advances in the development and wide use of influenza vaccines. Vaccination with traditional inactivate influenza vaccines (IIV) or live-attenuated influenza vaccines (LAIV) remains the main strategy in the control of annual seasonal epidemics, but it does not offer protection against new influenza viruses with pandemic potential, those that have shifted. Moreover, the continual antigenic drift of seasonal circulating influenza viruses, causing an antigenic mismatch that requires yearly reformulation of seasonal influenza vaccines, seriously compromises vaccine efficacy. Therefore, the quick optimization of vaccine production for seasonal influenza and the development of new vaccine approaches for pandemic viruses is still a challenge for the prevention of influenza infections. Moreover, recent reports have questioned the effectiveness of the current LAIV because of limited protection, mainly against the influenza A virus (IAV) component of the vaccine. Although the reasons for the poor protection efficacy of the LAIV have not yet been elucidated, researchers are encouraged to develop new vaccination approaches that overcome the limitations that are associated with the current LAIV. The discovery and implementation of plasmid-based reverse genetics has been a key advance in the rapid generation of recombinant attenuated influenza viruses that can be used for the development of new and most effective LAIV. In this review, we provide an update regarding the progress that has been made during the last five years in the development of new LAIV and the innovative ways that are being explored as alternatives to the currently licensed LAIV. The safety, immunogenicity, and protection efficacy profile of these new LAIVs reveal their possible implementation in combating influenza infections. However, efforts by vaccine companies and government agencies will be needed for controlled testing and approving, respectively, these new vaccine methodologies for the control of influenza infections.

Download Full-text

Hide and seek: interplay between influenza viruses and B cells

International Immunology ◽

10.1093/intimm/dxaa028 ◽

2020 ◽

Vol 32 (9) ◽

pp. 605-611 ◽

Cited By ~ 2

Author(s):

Masayuki Kuraoka ◽

Yu Adachi ◽

Yoshimasa Takahashi

Keyword(s):

B Cells ◽

B Cell ◽

Surface Protein ◽

Influenza Viruses ◽

Influenza Vaccines ◽

Native Structure ◽

Humoral Immune ◽

Protective Antibodies ◽

Major Surface ◽

And Function

Abstract Influenza virus constantly acquires genetic mutations/reassortment in the major surface protein, hemagglutinin (HA), resulting in the generation of strains with antigenic variations. There are, however, HA epitopes that are conserved across influenza viruses and are targeted by broadly protective antibodies. A goal for the next-generation influenza vaccines is to stimulate B-cell responses against such conserved epitopes in order to provide broad protection against divergent influenza viruses. Broadly protective B cells, however, are not easily activated by HA antigens with native structure, because the virus has multiple strategies to escape from the humoral immune responses directed to the conserved epitopes. One such strategy is to hide the conserved epitopes from the B-cell surveillance by steric hindrance. Technical advancement in the analysis of the human B-cell antigen receptor (BCR) repertoire has dissected the BCRs to HA epitopes that are hidden in the native structure but are targeted by broadly protective antibodies. We describe here the characterization and function of broadly protective antibodies and strategies that enable B cells to seek these hidden epitopes, with potential implications for the development of universal influenza vaccines.

Download Full-text

Immune Responses Elicited by Live Attenuated Influenza Vaccines as Correlates of Universal Protection against Influenza Viruses

Vaccines ◽

10.3390/vaccines9040353 ◽

2021 ◽

Vol 9 (4) ◽

pp. 353

Author(s):

Yo Han Jang ◽

Baik L. Seong

Keyword(s):

Immune Responses ◽

Neutralizing Antibodies ◽

Influenza Virus Infection ◽

Influenza Viruses ◽

Influenza Vaccines ◽

Immune Correlates ◽

Protection Efficacy ◽

Public Health Challenge ◽

Efficient Protection ◽

Universal Influenza Vaccine

Influenza virus infection remains a major public health challenge, causing significant morbidity and mortality by annual epidemics and intermittent pandemics. Although current seasonal influenza vaccines provide efficient protection, antigenic changes of the viruses often significantly compromise the protection efficacy of vaccines, rendering most populations vulnerable to the viral infection. Considerable efforts have been made to develop a universal influenza vaccine (UIV) able to confer long-lasting and broad protection. Recent studies have characterized multiple immune correlates required for providing broad protection against influenza viruses, including neutralizing antibodies, non-neutralizing antibodies, antibody effector functions, T cell responses, and mucosal immunity. To induce broadly protective immune responses by vaccination, various strategies using live attenuated influenza vaccines (LAIVs) and novel vaccine platforms are under investigation. Despite superior cross-protection ability, very little attention has been paid to LAIVs for the development of UIV. This review focuses on immune responses induced by LAIVs, with special emphasis placed on the breadth and the potency of individual immune correlates. The promising prospect of LAIVs to serve as an attractive and reliable vaccine platforms for a UIV is also discussed. Several important issues that should be addressed with respect to the use of LAIVs as UIV are also reviewed.

Download Full-text

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.

Download Full-text

Animal Models for Influenza Research: Strengths and Weaknesses

Viruses ◽

10.3390/v13061011 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1011

Author(s):

Thi-Quyen Nguyen ◽

Rare Rollon ◽

Young-Ki Choi

Keyword(s):

Animal Model ◽

Animal Models ◽

Research Question ◽

Viral Pathogenesis ◽

Influenza Viruses ◽

High Morbidity ◽

Host Immune Responses ◽

Transmission Mechanisms ◽

Significant Public Health ◽

Seasonal Epidemics

Influenza remains one of the most significant public health threats due to its ability to cause high morbidity and mortality worldwide. Although understanding of influenza viruses has greatly increased in recent years, shortcomings remain. Additionally, the continuous mutation of influenza viruses through genetic reassortment and selection of variants that escape host immune responses can render current influenza vaccines ineffective at controlling seasonal epidemics and potential pandemics. Thus, there is a knowledge gap in the understanding of influenza viruses and a corresponding need to develop novel universal vaccines and therapeutic treatments. Investigation of viral pathogenesis, transmission mechanisms, and efficacy of influenza vaccine candidates requires animal models that can recapitulate the disease. Furthermore, the choice of animal model for each research question is crucial in order for researchers to acquire a better knowledge of influenza viruses. Herein, we reviewed the advantages and limitations of each animal model—including mice, ferrets, guinea pigs, swine, felines, canines, and non-human primates—for elucidating influenza viral pathogenesis and transmission and for evaluating therapeutic agents and vaccine efficacy.

Download Full-text

Inhibition of ciliary activity in organ cultures of ferret trachea in reference to genetic and biological characters of influenza virus strains

Canadian Journal of Microbiology ◽

10.1139/m82-122 ◽

1982 ◽

Vol 28 (7) ◽

pp. 809-814 ◽

Cited By ~ 3

Author(s):

P. Diaz-Rodriguez ◽

A. Boudreault

Keyword(s):

Influenza Virus ◽

Influenza Viruses ◽

Influenza Vaccines ◽

Ciliary Activity ◽

Organ Cultures ◽

Preliminary Screening ◽

Cold Adapted ◽

Activity Inhibition ◽

Biological Characters ◽

Virus Strains

As reported previously, attenuated stable inhibitor-resistant influenza viruses can be screened by a 50% ciliary activity inhibition test in ferret tracheal organ cultures. This test was further applied to 5 attenuated cold-adapted influenza strains and to 11 strains with known a percentage of RNA–RNA hybridization with the parental A/PR/8/34 (H0N1) virus strain. Again, with one exception, attenuated strains could be clearly differentiated from virulent ones. It was concluded that virulence of influenza strains for man can be detected using this test regardless of the techniques used to prepare attenuated variants. A preliminary screening of attenuated candidates for live influenza vaccines can be achieved with confidence on ferret tracheal organ cultures.

Download Full-text

Influenza virus N-linked glycosylation and innate immunity

Bioscience Reports ◽

10.1042/bsr20171505 ◽

2019 ◽

Vol 39 (1) ◽

Cited By ~ 14

Author(s):

Ian A. York ◽

James Stevens ◽

Irina V. Alymova

Keyword(s):

Immune Responses ◽

Evolutionary Dynamics ◽

Analytical Techniques ◽

Influenza Viruses ◽

Innate Immune ◽

Global Public Health ◽

Innate Immune Responses ◽

Critical Determinant ◽

Public Health Challenge ◽

Seasonal Epidemics

AbstractInfluenza viruses cause seasonal epidemics and sporadic pandemics in humans. The virus’s ability to change its antigenic nature through mutation and recombination, and the difficulty in developing highly effective universal vaccines against it, make it a serious global public health challenge. Influenza virus’s surface glycoproteins, hemagglutinin and neuraminidase, are all modified by the host cell’s N-linked glycosylation pathways. Host innate immune responses are the first line of defense against infection, and glycosylation of these major antigens plays an important role in the generation of host innate responses toward the virus. Here, we review the principal findings in the analytical techniques used to study influenza N-linked glycosylation, the evolutionary dynamics of N-linked glycosylation in seasonal versus pandemic and zoonotic strains, its role in host innate immune responses, and the prospects for lectin-based therapies. As the efficiency of innate immune responses is a critical determinant of disease severity and adaptive immunity, the study of influenza glycobiology is of clinical as well as research interest.

Download Full-text