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

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.

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Development of Universal Influenza Vaccines Targeting Conserved Viral Proteins

Vaccines ◽

10.3390/vaccines7040169 ◽

2019 ◽

Vol 7 (4) ◽

pp. 169 ◽

Cited By ~ 8

Author(s):

Jazayeri ◽

Poh

Keyword(s):

Immune Responses ◽

Influenza Vaccine ◽

Neutralizing Antibodies ◽

Influenza Viruses ◽

Surface Proteins ◽

Influenza Vaccines ◽

Influenza Pandemics ◽

Host Immune Responses ◽

Production Platform ◽

Universal Influenza Vaccine

Vaccination is still the most efficient way to prevent an infection with influenza viruses. Nevertheless, existing commercial vaccines face serious limitations such as availability during epidemic outbreaks and their efficacy. Existing seasonal influenza vaccines mostly induce antibody responses to the surface proteins of influenza viruses, which frequently change due to antigenic shift and or drift, thus allowing influenza viruses to avoid neutralizing antibodies. Hence, influenza vaccines need a yearly formulation to protect against new seasonal viruses. A broadly protective or universal influenza vaccine must induce effective humoral as well as cellular immunity against conserved influenza antigens, offer good protection against influenza pandemics, be safe, and have a fast production platform. Nanotechnology has great potential to improve vaccine delivery, immunogenicity, and host immune responses. As new strains of human epidemic influenza virus strains could originate from poultry and swine viruses, development of a new universal influenza vaccine will require the immune responses to be directed against viruses from different hosts. This review discusses how the new vaccine platforms and nanoparticles can be beneficial in the development of a broadly protective, universal influenza vaccine.

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Next Generation of Computationally Optimized Broadly Reactive HA Vaccines Elicited Cross-Reactive Immune Responses and Provided Protection against H1N1 Virus Infection

Vaccines ◽

10.3390/vaccines9070793 ◽

2021 ◽

Vol 9 (7) ◽

pp. 793

Author(s):

Ying Huang ◽

Monique S. França ◽

James D. Allen ◽

Hua Shi ◽

Ted M. Ross

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Immune Responses ◽

H1n1 Virus ◽

Influenza Virus Infection ◽

H1n1 Influenza ◽

Influenza Viruses ◽

Next Generation ◽

Wild Type ◽

Influenza A H1n1

Vaccination is the best way to prevent influenza virus infections, but the diversity of antigenically distinct isolates is a persistent challenge for vaccine development. In order to conquer the antigenic variability and improve influenza virus vaccine efficacy, our research group has developed computationally optimized broadly reactive antigens (COBRAs) in the form of recombinant hemagglutinins (rHAs) to elicit broader immune responses. However, previous COBRA H1N1 vaccines do not elicit immune responses that neutralize H1N1 virus strains in circulation during the recent years. In order to update our COBRA vaccine, two new candidate COBRA HA vaccines, Y2 and Y4, were generated using a new seasonal-based COBRA methodology derived from H1N1 isolates that circulated during 2013–2019. In this study, the effectiveness of COBRA Y2 and Y4 vaccines were evaluated in mice, and the elicited immune responses were compared to those generated by historical H1 COBRA HA and wild-type H1N1 HA vaccines. Mice vaccinated with the next generation COBRA HA vaccines effectively protected against morbidity and mortality after infection with H1N1 influenza viruses. The antibodies elicited by the COBRA HA vaccines were highly cross-reactive with influenza A (H1N1) pdm09-like viruses isolated from 2009 to 2021, especially with the most recent circulating viruses from 2019 to 2021. Furthermore, viral loads in lungs of mice vaccinated with Y2 and Y4 were dramatically reduced to low or undetectable levels, resulting in minimal lung injury compared to wild-type HA vaccines following H1N1 influenza virus infection.

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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.

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Influenza Anti-Stalk Antibodies: Development of a New Method for the Evaluation of the Immune Responses to Universal Vaccine

Vaccines ◽

10.3390/vaccines8010043 ◽

2020 ◽

Vol 8 (1) ◽

pp. 43 ◽

Cited By ~ 3

Author(s):

Alessandro Manenti ◽

Agnieszka Katarzyna Maciola ◽

Claudia Maria Trombetta ◽

Otfried Kistner ◽

Elisa Casa ◽

...

Keyword(s):

Immune Responses ◽

Competitive Elisa ◽

Influenza Vaccines ◽

Elisa Method ◽

Serum Samples ◽

Universal Vaccine ◽

Administration Routes ◽

Hemagglutinin Protein ◽

Protective Antibodies ◽

Universal Influenza Vaccine

Growing interest in universal influenza vaccines and novel administration routes has led to the development of alternative serological assays that are able to detect antibodies against conserved epitopes. We present a competitive ELISA method that is able to accurately determine the ratio of serum immunoglobulin G directed against the different domains of the hemagglutinin, the head and the stalk. Human serum samples were treated with two variants of the hemagglutinin protein from the A/California/7/2009 influenza virus. The signals detected were assigned to different groups of antibodies and presented as a ratio between head and stalk domains. A subset of selected sera was also tested by hemagglutination inhibition, single radial hemolysis, microneutralization, and enzyme-linked lectin assays. Pre-vaccination samples from adults showed a quite high presence of anti-stalk antibodies, and the results were substantially in line with those of the classical serological assays. By contrast, pre-vaccination samples from children did not present anti-stalk antibodies, and the majority of the anti-hemagglutinin antibodies that were detected after vaccination were directed against the head domain. The presented approach, when supported by further assays, can be used to assess the presence of specific anti-stalk antibodies and the potential boost of broadly protective antibodies, especially in the case of novel universal influenza vaccine approaches.

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Comparison of A(H3N2) Neutralizing Antibody Responses Elicited by 2018–2019 Season Quadrivalent Influenza Vaccines Derived from Eggs, Cells, and Recombinant Hemagglutinin

Clinical Infectious Diseases ◽

10.1093/cid/ciaa1352 ◽

2020 ◽

Author(s):

Wei Wang ◽

Esmeralda Alvarado-Facundo ◽

Russell Vassell ◽

Limone Collins ◽

Rhonda E Colombo ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Neutralizing Antibody ◽

Vaccine Virus ◽

Influenza Viruses ◽

Antigenic Drift ◽

Influenza Vaccines ◽

Open Label ◽

Virus Propagation ◽

Vaccine Antigens ◽

H3n2 Influenza

Abstract Background Low vaccine effectiveness against A(H3N2) influenza in seasons with little antigenic drift has been attributed to substitutions in hemagglutinin (HA) acquired during vaccine virus propagation in eggs. Clinical trials comparing recombinant HA vaccine (rHA) and cell-derived inactivated influenza vaccine (IIV) to egg-derived IIVs provide opportunities to assess how egg-adaptive substitutions influence HA immunogenicity. Methods Neutralization titers in pre- and postimmunization sera from 133 adults immunized with 1 of 3 types of influenza vaccines in a randomized, open-label trial during the 2018–2019 influenza season were measured against egg- and cell-derived A/Singapore/INFIMH-16-0019/2016-like and circulating A(H3N2) influenza viruses using HA pseudoviruses. Results All vaccines elicited neutralizing antibodies to all H3 vaccine antigens, but the rHA vaccine elicited the highest titers and seroconversion rates against all strains tested. Egg- and cell-derived IIVs elicited responses similar to each other. Preimmunization titers against H3 HA pseudoviruses containing egg-adaptive substitutions T160K and L194P were high, but lower against H3 HA pseudoviruses without those substitutions. All vaccines boosted neutralization titers against HA pseudoviruses with egg-adaptive substitutions, but poorly neutralized wild-type 2019–2020 A/Kansas/14/2017 (H3N2) HA pseudoviruses. Conclusion Egg- and cell-derived 2018–2019 season influenza vaccines elicited similar neutralization titers and response rates, indicating that the cell-derived vaccine did not improve immunogenicity against the A(H3N2) viruses. The higher responses after rHA vaccination may be due to its higher HA content. All vaccines boosted titers to HA with egg-adaptive substitutions, suggesting boosting from past antigens or better exposure of HA epitopes. Studies comparing immunogenicity and effectiveness of different influenza vaccines across many seasons are needed.

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Potency of an Inactivated Influenza Vaccine against a Challenge with A/Swine/Missouri/A01727926/2015 (H4N6) in Mice for Pandemic Preparedness

Vaccines ◽

10.3390/vaccines8040768 ◽

2020 ◽

Vol 8 (4) ◽

pp. 768

Author(s):

Hirotaka Hayashi ◽

Norikazu Isoda ◽

Enkhbold Bazarragchaa ◽

Naoki Nomura ◽

Keita Matsuno ◽

...

Keyword(s):

Influenza Virus ◽

Virus Infection ◽

Neutralizing Antibodies ◽

Influenza Pandemic ◽

Influenza Virus Infection ◽

Cross Reactivity ◽

Influenza Viruses ◽

Pandemic Preparedness ◽

Antigenic Relation ◽

High Immunogenicity

H4 influenza viruses have been isolated from birds across the world. In recent years, an H4 influenza virus infection has been confirmed in pigs. Pigs play an important role in the transmission of influenza viruses to human hosts. Therefore, it is important to develop a new vaccine in the case of an H4 influenza virus infection in humans, considering that this virus has a different antigenicity from seasonal human influenza viruses. In this study, after selecting vaccine candidate strains based on their antigenic relation to one of the pig isolates, A/swine/Missouri/A01727926/2015 (H4N6) (MO/15), an inactivated whole-particle vaccine was prepared from A/swan/Hokkaido/481102/2017 (H4N6). This vaccine showed high immunogenicity in mice, and the antibody induced by the vaccine showed high cross-reactivity to the MO/15 virus. This vaccine induced sufficient neutralizing antibodies and mitigated the effects of an MO/15 infection in a mouse model. This study is the first to suggest that an inactivated whole-particle vaccine prepared from an influenza virus isolated from wild birds is an effective countermeasure in case of a future influenza pandemic caused by the H4 influenza virus.

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Influenza A Virus Vaccination: Immunity, Protection, and Recent Advances Toward A Universal Vaccine

Vaccines ◽

10.3390/vaccines8030434 ◽

2020 ◽

Vol 8 (3) ◽

pp. 434 ◽

Cited By ~ 2

Author(s):

Christopher E. Lopez ◽

Kevin L. Legge

Keyword(s):

Immune Response ◽

Influenza Virus ◽

Virus Infection ◽

Influenza A ◽

Influenza Virus Infection ◽

Influenza Viruses ◽

Antigenic Drift ◽

Influenza Vaccines ◽

Virus Infections ◽

Universal Vaccine

Influenza virus infections represent a serious public health threat and account for significant morbidity and mortality worldwide due to seasonal epidemics and periodic pandemics. Despite being an important countermeasure to combat influenza virus and being highly efficacious when matched to circulating influenza viruses, current preventative strategies of vaccination against influenza virus often provide incomplete protection due the continuous antigenic drift/shift of circulating strains of influenza virus. Prevention and control of influenza virus infection with vaccines is dependent on the host immune response induced by vaccination and the various vaccine platforms induce different components of the local and systemic immune response. This review focuses on the immune basis of current (inactivated influenza vaccines (IIV) and live attenuated influenza vaccines (LAIV)) as well as novel vaccine platforms against influenza virus. Particular emphasis will be placed on how each platform induces cross-protection against heterologous influenza viruses, as well as how this immunity compares to and contrasts from the “gold standard” of immunity generated by natural influenza virus infection.

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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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H5N1 influenza virus-like particles produced by transient expression in mammalian cells induce humoral and cellular immune responses in mice

Canadian Journal of Microbiology ◽

10.1139/w2012-006 ◽

2012 ◽

Vol 58 (4) ◽

pp. 391-401 ◽

Cited By ~ 4

Author(s):

Ling Tao ◽

Jianjun Chen ◽

Zhenhua Zheng ◽

Jin Meng ◽

Zhenfeng Zhang ◽

...

Keyword(s):

Influenza Virus ◽

Immune Responses ◽

Cleavage Site ◽

Mammalian Cells ◽

Influenza Virus Infection ◽

Influenza Viruses ◽

Virus Like Particles ◽

Cellular Immune Responses ◽

H5n1 Influenza ◽

Cellular Immune

Vaccination is an effective way to protect from influenza virus infection. Among the new candidates of influenza vaccines, influenza virus-like particles (VLPs) seem to be promising. Here, we generated 2 types of H5N1 influenza VLPs by co-expressing influenza virus Env (envelope protein) and murine leukemia virus (MLV) Gag–Pol. VLPs generated by co-transfection of pHCMV-wtH5 or pHCMV-mtH5 with pSV-Mo-MLVgagpol and pHCMV-N1 were named as wtH5N1 VLPs or mtH5N1 VLPs. The plasmid of pHCMV-wtH5 encoded the wild-type hemagglutinin (HA) (wtH5) from A/swine/Anhui/ca/2004 (H5N1) with a multibasic cleavage site, while pHCMV-mtH5 encoded the modified mutant-type (mtH5) with a monobasic cleavage site. Influenza virus HA VLPs were characterized and equal amounts of them were used to immunize mice subcutaneously, intraperitoneally, or intramuscularly. The levels of HA-specific IgG1, IFN-γ, and neutralization antibodies were significantly induced in mice immunized with wtH5N1 VLPs or mtH5N1 VLPs via all 3 routes, while HA-specific IgG2a was barely detectable. IL-4 secretion was detected in mice subcutaneously immunized with wtH5N1 VLPs or mtH5N1 VLPs, or intramuscularly immunized with mtH5N1 VLPs. Our results indicated that both H5N1 influenza VLPs could induce specific humoral and cellular immune responses in immunized mice. In conclusion, our study provides helpful information for designing new candidate vaccines against H5N1 influenza viruses.

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