scholarly journals The role of gene segment interactions in driving the emergence of dominant gene constellations during influenza virus reassortment

2021 ◽  
Author(s):  
Sanja Trifkovic ◽  
Brad Gilbertson ◽  
Emily Fairmaid ◽  
Joanna Cobbin ◽  
Steven Rockman ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Selective Pressure ◽  
Gene Segment ◽  
Dominant Gene ◽  
Influenza Vaccines ◽  
Production Model ◽  
Virus Reassortment ◽  
Segmented Genome

AbstractA segmented genome enables influenza virus to undergo reassortment when two viruses infect the same cell. Resulting reassorted progeny have a spectrum of gene constellations and potentially different phenotypes. Although reassortment is involved in the creation of pandemic influenza strains and is routinely used to produce influenza vaccines, our understanding of the factors that drive the emergence of dominant gene constellations during this process is incomplete. Using an influenza vaccine seed production model, reassortant genotypes were tracked through the reassortment process under antibody selective pressure. We discovered that certain gene constellations conferring low replicative fitness were selected at the expense of more fit progeny. Nevertheless, relatively unfit reassortants likely provide high hemagglutinin antigen yields through co-production of non-infectious particles and/or by more hemagglutinin molecules per virion. Our data illustrate the dynamics and complexity of reassortment and highlight how gene segment interactions formed during packaging, in addition to antibody pressure, restrict the final viruses that dominate.

scholarly journals Gene Segment Interactions Can Drive the Emergence of Dominant Yet Suboptimal Gene Constellations During Influenza Virus Reassortment

2021 ◽  
Vol 12 ◽  
Author(s):  
Sanja Trifkovic ◽  
Brad Gilbertson ◽  
Emily Fairmaid ◽  
Joanna Cobbin ◽  
Steven Rockman ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Major Gene ◽  
Gene Segment ◽  
Dominant Gene ◽  
Production Model ◽  
Virus Particles ◽  
Virus Reassortment ◽  
Reassortant Viruses ◽  
The Impact

A segmented genome enables influenza virus to undergo reassortment when two viruses infect the same cell. Although reassortment is involved in the creation of pandemic influenza strains and is routinely used to produce influenza vaccines, our understanding of the factors that drive the emergence of dominant gene constellations during this process is incomplete. Recently, we defined a spectrum of interactions between the gene segments of the A/Udorn/307/72 (H3N2) (Udorn) strain that occur within virus particles, a major interaction being between the NA and PB1 gene segments. In addition, we showed that the Udorn PB1 is preferentially incorporated into reassortant viruses that express the Udorn NA. Here we use an influenza vaccine seed production model where eggs are coinfected with Udorn and the high yielding A/Puerto Rico/8/34 (H1N1) (PR8) virus and track viral genotypes through the reassortment process under antibody selective pressure to determine the impact of Udorn NA-PB1 co-selection. We discovered that 86% of the reassortants contained the PB1 from the Udorn parent after the initial co-infection and this bias towards Udorn PB1 was maintained after two further passages. Included in these were certain gene constellations containing Udorn HA, NA, and PB1 that confered low replicative fitness yet rapidly became dominant at the expense of more fit progeny, even when co-infection ratios of the two viruses favoured PR8. Fitness was not compromised, however, in the corresponding reassortants that also contained Udorn NP. Of particular note is the observation that relatively unfit reassortants could still fulfil the role of vaccine seed candidates as they provided high haemagglutinin (HA) antigen yields through co-production of non-infectious particles and/or by more HA molecules per virion. Our data illustrate the dynamics and complexity of reassortment and highlight how major gene segment interactions formed during packaging, in addition to antibody pressure, initially restrict the reassortant viruses that are formed.

scholarly journals Host Factors Impact Vaccine Efficacy: Implications for Seasonal and Universal Influenza Vaccine Programs

2019 ◽  
Vol 93 (21) ◽  
Author(s):  
Santosh Dhakal ◽  
Sabra L. Klein
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Virus Vaccine ◽  
Vaccine Efficacy ◽  
Public Health Problem ◽  
Influenza Virus Vaccine ◽  
Host Factors ◽  
Influenza Vaccines ◽  
Vaccine Type ◽  
Induced Immunity

ABSTRACT Influenza is a global public health problem. Current seasonal influenza vaccines have highly variable efficacy, and thus attempts to develop broadly protective universal influenza vaccines with durable protection are under way. While much attention is given to the virus-related factors contributing to inconsistent vaccine responses, host-associated factors are often neglected. Growing evidences suggest that host factors including age, biological sex, pregnancy, and immune history play important roles as modifiers of influenza virus vaccine efficacy. We hypothesize that host genetics, the hormonal milieu, and gut microbiota contribute to host-related differences in influenza virus vaccine efficacy. This review highlights the current insights and future perspectives into host-specific factors that impact influenza vaccine-induced immunity and protection. Consideration of the host factors that affect influenza vaccine-induced immunity might improve influenza vaccines by providing empirical evidence for optimizing or even personalizing vaccine type, dose, and use of adjuvants for current seasonal and future universal influenza vaccines.

scholarly journals Comparisons of the Humoral and Cellular Immune Responses Induced by Live Attenuated Influenza Vaccine and Inactivated Influenza Vaccine in Adults

2016 ◽  
Vol 24 (1) ◽  
Author(s):  
Daniel F. Hoft ◽  
Kathleen R. Lottenbach ◽  
Azra Blazevic ◽  
Aldin Turan ◽  
Tamara P. Blevins ◽  
...  
Keyword(s):  
Influenza Virus ◽  
T Cell ◽  
Young Children ◽  
Influenza Vaccine ◽  
T Cell Responses ◽  
Influenza Vaccines ◽  
Secretory Iga ◽  
Cell Responses ◽  
Live Attenuated Influenza Vaccine ◽  
Cellular Immune

ABSTRACT Both live attenuated influenza vaccines (LAIV) and inactivated influenza vaccines (IIV) induce protective immunity against influenza. There is evidence that LAIV induces superior protection in children, whereas IIV may induce superior protection in adults. The immune mechanisms responsible for these differences have not been identified. We previously compared LAIV and IIV in young children of 6 to 36 months of age, and we demonstrated that while both induced similar hemagglutination inhibition (HAI) antibody responses, only LAIV induced significant increases in T cell responses. In the present study, 37 healthy adult subjects of 18 to 49 years of age were randomized to receive seasonal influenza vaccination with LAIV or IIV. Influenza virus-specific HAI, T cell, and secretory IgA (sIgA) responses were studied pre- and postvaccination. In contrast to the responses seen in young children, LAIV induced only minimal increases in serum HAI responses in adults, which were significantly lower than the responses induced by IIV. Both LAIV and IIV similarly induced only transient T cell responses to replication-competent whole virus in adults. In contrast, influenza virus-specific sIgA responses were induced more strongly by LAIV than by IIV. Our previous studies suggest that LAIV may be more protective than IIV in young children not previously exposed to influenza virus or influenza vaccines due to increased vaccine-induced T cell and/or sIgA responses. Our current work suggests that in adults with extensive and partially cross-reactive preexisting influenza immunity, LAIV boosting of sIgA responses to hemagglutinin (HA) and non-HA antigenic targets expressed by circulating influenza virus strains may be an important additional mechanism of vaccine-induced immunity.

scholarly journals Development of a Pan-H1 Influenza Vaccine

2018 ◽  
Vol 92 (22) ◽  
Author(s):  
Nicole Darricarrère ◽  
Svetlana Pougatcheva ◽  
Xiaochu Duan ◽  
Rebecca S. Rudicell ◽  
Te-Hui Chou ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Immune Responses ◽  
Influenza Vaccine ◽  
Seasonal Influenza ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
The Past ◽  
Individual Strain ◽  
Humoral Responses ◽  
Virus Strains

ABSTRACT The efficacy of current seasonal influenza vaccines varies greatly, depending on the match to circulating viruses. Although most vaccines elicit strain-specific responses, some present cross-reactive epitopes that elicit antibodies against diverse viruses and remain unchanged and effective for several years. To determine whether combinations of specific H1 hemagglutinin (HA) antigens stimulate immune responses that protect against diverse H1 influenza viruses, we evaluated the antibody responses elicited by HA-ferritin nanoparticles derived from six evolutionarily divergent H1 sequences and two computationally optimized broadly reactive antigen (COBRA) HA antigens. Humoral responses were assessed against a panel of 16 representative influenza virus strains from the past 80 years. HAs from the strains A/NewCaledonia/20/1999 (NC99), A/California/04/2009 (CA09), A/HongKong/117/1977 (HK77), COBRA X6, or P1 elicited neutralization against diverse strains, and a combination of three wild-type HA or two COBRA HA nanoparticles conferred significant additional breadth beyond that observed with any individual strain. Therefore, combinations of H1 HAs may constitute a pan-H1 influenza vaccine. IMPORTANCE Seasonal influenza vaccines elicit strain-specific immune responses designed to protect against circulating viruses. Because these vaccines often show limited efficacy, the search for a broadly protective seasonal vaccine remains a priority. Among different influenza virus subtypes, H1N1 has long been circulating in humans and has caused pandemic outbreaks. In order to assess the potential of a multivalent HA combination vaccine to improve the breadth of protection against divergent H1N1 viruses, HA-ferritin nanoparticles were made and evaluated in mice against a panel of historical and contemporary influenza virus strains. Trivalent combinations of H1 nanoparticles improved the breadth of immunity against divergent H1 influenza viruses.

scholarly journals Computationally Optimized Broadly Reactive Hemagglutinin Elicits Hemagglutination Inhibition Antibodies against a Panel of H3N2 Influenza Virus Cocirculating Variants

2017 ◽  
Vol 91 (24) ◽  
Author(s):  
Terianne M. Wong ◽  
James D. Allen ◽  
Anne-Gaelle Bebin-Blackwell ◽  
Donald M. Carter ◽  
Timothy Alefantis ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Influenza B ◽  
Wild Type ◽  
Protective Antibodies ◽  
H3n2 Influenza ◽  
H3n2 Influenza Virus

ABSTRACT Each influenza season, a set of wild-type viruses, representing one H1N1, one H3N2, and one to two influenza B isolates, are selected for inclusion in the annual seasonal influenza vaccine. In order to develop broadly reactive subtype-specific influenza vaccines, a methodology called computationally optimized broadly reactive antigens (COBRA) was used to design novel hemagglutinin (HA) vaccine immunogens. COBRA technology was effectively used to design HA immunogens that elicited antibodies that neutralized H5N1 and H1N1 isolates. In this report, the development and characterization of 17 prototype H3N2 COBRA HA proteins were screened in mice and ferrets for the elicitation of antibodies with HA inhibition (HAI) activity against human seasonal H3N2 viruses that were isolated over the last 48 years. The most effective COBRA HA vaccine regimens elicited antibodies with broader HAI activity against a panel of H3N2 viruses than wild-type H3 HA vaccines. The top leading COBRA HA candidates were tested against cocirculating variants. These variants were not efficiently detected by antibodies elicited by the wild-type HA from viruses selected as the vaccine candidates. The T-11 COBRA HA vaccine elicited antibodies with HAI and neutralization activity against all cocirculating variants from 2004 to 2007. This is the first report demonstrating broader breadth of vaccine-induced antibodies against cocirculating H3N2 strains compared to the wild-type HA antigens that were represented in commercial influenza vaccines. IMPORTANCE There is a need for an improved influenza vaccine that elicits immune responses that recognize a broader number of influenza virus strains to prevent infection and transmission. Using the COBRA approach, a set of vaccines against influenza viruses in the H3N2 subtype was tested for the ability to elicit antibodies that neutralize virus infection against not only historical vaccine strains of H3N2 but also a set of cocirculating variants that circulated between 2004 and 2007. Three of the H3N2 COBRA vaccines recognized all of the cocirculating strains during this era, but the chosen wild-type vaccine strains were not able to elicit antibodies with HAI activity against these cocirculating strains. Therefore, the COBRA vaccines have the ability to elicit protective antibodies against not only the dominant vaccine strains but also minor circulating strains that can evolve into the dominant vaccine strains in the future.

scholarly journals Designed Nanoparticles Elicit Cross-Reactive Antibody Responses To Conserved Influenza Virus Hemagglutinin Stem Epitopes

2019 ◽  
Author(s):  
Dustin M. McCraw ◽  
Mallory L. Myers ◽  
Neetu M. Gulati ◽  
John R. Gallagher ◽  
Alexander J. Kim ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Vaccine Development ◽  
Cross Reactivity ◽  
Surface Glycoprotein ◽  
Influenza Vaccines ◽  
Health Concern ◽  
Public Health Issue ◽  
Lethal Challenge ◽  
Universal Influenza Vaccine

AbstractDespite the availability of seasonal vaccines and antiviral medications, influenza virus continues to be a major health concern and pandemic threat due to the continually changing antigenic regions of the major surface glycoprotein, hemagglutinin (HA). One emerging strategy for the development of more efficacious seasonal and universal influenza vaccines is structure-guided design of nanoparticles that display conserved regions of HA, such as the stem. Using the H1 HA subtype to establish proof of concept, we found that an alpha-helical fragment (helix-A) from the conserved stem region can be displayed on nanoparticles. The stem region of HA on these nanoparticles is immunogenic and the nanoparticles are biochemically robust in that heat exposure did not destroy the particles and immunogenicity was retained. Furthermore, H1-nanoparticles protected mice from lethal challenge with H1N1 influenza virus. Importantly, antibodies elicited by these nanoparticles demonstrated homosubtypic and heterosubtypic cross-reactivity. The helix-A stem nanoparticle design represents a novel approach to display several hundred copies of non-trimeric conserved HA stem epitopes on vaccine nanoparticles. This design concept provides a new approach to universal influenza vaccine development strategies and opens up opportunities for the development of nanoparticles with broad coverage over many antigenically diverse influenza HA subtypes.SignificanceInfluenza virus is a public health issue that affects millions of people globally each year. Commercial influenza vaccines are based on the hemagglutinin (HA) surface glycoprotein, which can change antigenically every year, demanding the manufacture of newly matched vaccines annually. HA stem epitopes have a higher degree of conservation than HA molecules contained in conventional vaccine formulations and we demonstrate that we are able to design nanoparticles that display hundreds of HA stem fragments on nanoparticles. These designed nanoparticles are heat-stable, elicit antibodies to the HA stem, confer protection in mouse challenge models, and show cross-reactivity between HA subtypes. This technology provides promising opportunities to improve seasonal vaccines, develop pandemic preparedness vaccines, and facilitate the development of a universal influenza vaccine.

scholarly journals Strategies Targeting Hemagglutinin as a Universal Influenza Vaccine

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 257
Author(s):  
Brianna L. Bullard ◽  
Eric A. Weaver
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Vaccine Efficacy ◽  
Influenza Season ◽  
Surface Protein ◽  
Antigenic Drift ◽  
Influenza Vaccines ◽  
Viral Diversity ◽  
Universal Influenza Vaccine ◽  
Ha Protein

Influenza virus has significant viral diversity, both through antigenic drift and shift, which makes development of a vaccine challenging. Current influenza vaccines are updated yearly to include strains predicted to circulate in the upcoming influenza season, however this can lead to a mismatch which reduces vaccine efficacy. Several strategies targeting the most abundant and immunogenic surface protein of influenza, the hemagglutinin (HA) protein, have been explored. These strategies include stalk-directed, consensus-based, and computationally derived HA immunogens. In this review, we explore vaccine strategies which utilize novel antigen design of the HA protein to improve cross-reactive immunity for development of a universal influenza vaccine.

scholarly journals Contribution of Vaccine-Induced Immunity toward either the HA or the NA Component of Influenza Viruses Limits Secondary Bacterial Complications

2010 ◽  
Vol 84 (8) ◽  
pp. 4105-4108 ◽  
Author(s):  
Victor C. Huber ◽  
Ville Peltola ◽  
Amy R. Iverson ◽  
Jonathan A. McCullers
Keyword(s):  
Influenza Virus ◽  
Influenza Vaccine ◽  
Bacterial Infection ◽  
Virus Vaccine ◽  
Bacterial Infections ◽  
Influenza Virus Vaccine ◽  
Influenza Viruses ◽  
Influenza Vaccines ◽  
Secondary Infections ◽  
Induced Immunity

ABSTRACT Secondary bacterial infections contribute to morbidity and mortality from influenza. Vaccine effectiveness is typically assessed using prevention of influenza, not secondary infections, as an endpoint. We vaccinated mice with formalin-inactivated influenza virus vaccine preparations containing disparate HA and NA proteins and demonstrated an ability to induce the appropriate anti-HA and anti-NA immune profiles. Protection from both primary viral and secondary bacterial infection was demonstrated with vaccine-induced immunity directed toward either the HA or the NA. This finding suggests that immunity toward the NA component of the virion is desirable and should be considered in generation of influenza vaccines.

scholarly journals A Viable Recombinant Rhabdovirus Lacking Its Glycoprotein Gene and Expressing Influenza Virus Hemagglutinin and Neuraminidase Is a Potent Influenza Vaccine

2014 ◽  
Vol 89 (5) ◽  
pp. 2820-2830 ◽  
Author(s):  
Alex B. Ryder ◽  
Linda Buonocore ◽  
Leatrice Vogel ◽  
Raffael Nachbagauer ◽  
Florian Krammer ◽  
...  
Keyword(s):  
Cell Culture ◽  
Influenza Virus ◽  
Influenza Vaccine ◽  
Vesicular Stomatitis Virus ◽  
Recombinant Virus ◽  
Vaccine Candidate ◽  
Influenza Vaccines ◽  
Glycoprotein Gene ◽  
Influenza Virus Hemagglutinin ◽  
Vesicular Stomatitis

ABSTRACTThe emergence of novel influenza viruses that cause devastating human disease is an ongoing threat and serves as an impetus for the continued development of novel approaches to influenza vaccines. Influenza vaccine development has traditionally focused on producing humoral and/or cell-mediated immunity, often against the viral surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Here, we describe a new vaccine candidate that utilizes a replication-defective vesicular stomatitis virus (VSV) vector backbone that lacks the native G surface glycoprotein gene (VSVΔG). The expression of the H5 HA of an H5N1 highly pathogenic avian influenza virus (HPAIV), A/Vietnam/1203/04 (VN1203), and the NA of the mouse-adapted H1N1 influenza virus A/Puerto Rico/8/34 (PR8) in the VSVΔG vector restored the ability of the recombinant virus to replicate in cell culture, without the requirement for the addition of trypsin. We show here that this recombinant virus vaccine candidate was nonpathogenic in mice when given by either the intramuscular or intranasal route of immunization and that thein vivoreplication of VSVΔG-H5N1 is profoundly attenuated. This recombinant virus also provided protection against lethal H5N1 infection after a single dose. This novel approach to vaccination against HPAIVs may be widely applicable to other emerging strains of influenza virus.IMPORTANCEPreparation for a potentially catastrophic influenza pandemic requires novel influenza vaccines that are safe, can be produced and administered quickly, and are effective, both soon after administration and for a long duration. We have created a new influenza vaccine that utilizes an attenuated vesicular stomatitis virus (VSV) vector, to deliver and express influenza virus proteins against which vaccinated animals develop potent antibody responses. The influenza virus hemagglutinin and neuraminidase proteins, expressed on the surface of VSV particles, allowed this vaccine to grow in cell culture and induced a potent antibody response in mice that was effective against infection with a lethal influenza virus. The mice showed no adverse reactions to the vaccine, and they were protected against an otherwise lethal influenza infection after only 14 days postvaccination and after as many as 140 days postvaccination. The ability to rapidly produce this safe and effective vaccine in cell culture is additionally advantageous.

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