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

Author(s):  
Wei Wang ◽  
Esmeralda Alvarado-Facundo ◽  
Russell Vassell ◽  
Limone Collins ◽  
Rhonda E Colombo ◽  
...  

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.

2021 ◽  
Vol 17 (4) ◽  
pp. e1009171
Author(s):  
Jin Gao ◽  
Hongquan Wan ◽  
Xing Li ◽  
Mira Rakic Martinez ◽  
Laura Klenow ◽  
...  

Virions are a common antigen source for many viral vaccines. One limitation to using virions is that the antigen abundance is determined by the content of each protein in the virus. This caveat especially applies to viral-based influenza vaccines where the low abundance of the neuraminidase (NA) surface antigen remains a bottleneck for improving the NA antibody response. Our systematic analysis using recent H1N1 vaccine antigens demonstrates that the NA to hemagglutinin (HA) ratio in virions can be improved by exchanging the viral backbone internal genes, especially the segment encoding the polymerase PB1 subunit. The purified inactivated virions with higher NA content show a more spherical morphology, a shift in the balance between the HA receptor binding and NA receptor release functions, and induce a better NA inhibitory antibody response in mice. These results indicate that influenza viruses support a range of ratios for a given NA and HA pair which can be used to produce viral-based influenza vaccines with higher NA content that can elicit more balanced neutralizing antibody responses to NA and HA.


2021 ◽  
Vol 12 ◽  
Author(s):  
James D. Allen ◽  
Ted M. Ross

Each person has a unique immune history to past influenza virus infections. Exposure to influenza viruses early in life establishes memory B cell populations that influence future immune responses to influenza vaccination. Current influenza vaccines elicit antibodies that are typically strain specific and do not offer broad protection against antigenically drifted influenza strains in all age groups of people. This is particularly true for vaccine antigens of the A(H3N2) influenza virus subtype, where continual antigenic drift necessitates frequent vaccine reformulation. Broadly-reactive influenza virus vaccine antigens offer a solution to combat antigenic drift, but they also need to be equally effective in all populations, regardless of prior influenza virus exposure history. This study examined the role that pre-existing immunity plays on influenza virus vaccination. Ferrets were infected with historical A(H3N2) influenza viruses isolated from either the 1970’s, 1980’s, or 1990’s and then vaccinated with computationally optimized broadly reactive antigens (COBRA) or wild-type (WT) influenza virus like particles (VLPs) expressing hemagglutinin (HA) vaccine antigens to examine the expansion of immune breadth. Vaccines with the H3 COBRA HA antigens had more cross-reactive antibodies following a single vaccination in all three pre-immune regimens than vaccines with WT H3 HA antigens against historical, contemporary, and future drifted A(H3N2) influenza viruses. The H3 COBRA HA vaccines also induced antibodies capable of neutralizing live virus infections against modern drifted A(H3N2) strains at higher titers than the WT H3 HA vaccine comparators.


Author(s):  
Seyhan Boyoglu-Barnum ◽  
Daniel Ellis ◽  
Rebecca A. Gillespie ◽  
Geoffrey B. Hutchinson ◽  
Young-Jun Park ◽  
...  

AbstractInfluenza vaccines that confer broad and durable protection against diverse virus strains would have a major impact on global health. However, next-generation vaccine design efforts have been complicated by challenges including the genetic plasticity of the virus and the immunodominance of certain epitopes in its glycoprotein antigens. Here we show that computationally designed, two-component nanoparticle immunogens induce potently neutralizing and broadly protective antibody responses against a wide variety of influenza viruses. The nanoparticle immunogens display 20 hemagglutinin (HA) trimers in a highly immunogenic array, and their assembly in vitro enables precisely controlled co-display of multiple distinct HAs in defined ratios. Nanoparticle immunogens displaying the four HAs of licensed quadrivalent influenza vaccines (QIV) elicited hemagglutination inhibition and neutralizing antibody responses to vaccine-matched strains that were equivalent or superior to commercial QIV in mice, ferrets, and nonhuman primates. The nanoparticle immunogens—but not QIV—simultaneously induced broadly protective antibody responses to heterologous viruses, including H5N1 and H7N9, by targeting the subdominant yet conserved HA stem. Unlike previously reported influenza vaccine candidates, our nanoparticle immunogens can alter the intrinsic immunodominance hierarchy of HA to induce both potent receptor-blocking and broadly cross-reactive stem-directed antibody responses and are attractive candidates for a next-generation influenza vaccine that could replace current seasonal vaccines.One Sentence SummaryNanoparticle immunogens displaying four seasonal influenza hemagglutinins elicit neutralizing antibodies directed at both the immunodominant head and the conserved stem and confer broad protective immunity.


Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 353
Author(s):  
Yo Han Jang ◽  
Baik L. Seong

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.


2020 ◽  
Vol 6 (2) ◽  
Author(s):  
B F Koel ◽  
R M Vigeveno ◽  
M Pater ◽  
S M Koekkoek ◽  
A X Han ◽  
...  

Abstract Seasonal human influenza viruses continually change antigenically to escape from neutralizing antibodies. It remains unclear how genetic variation in the intrahost virus population and selection at the level of individual hosts translates to the fast-paced evolution observed at the global level because emerging intrahost antigenic variants are rarely detected. We tracked intrahost variants in the hemagglutinin and neuraminidase surface proteins using longitudinally collected samples from 52 patients infected by A/H3N2 influenza virus, mostly young children, who received oseltamivir treatment. We identified emerging putative antigenic variants and oseltamivir-resistant variants, most of which remained detectable in samples collected at subsequent days, and identified variants that emerged intrahost immediately prior to increases in global rates. In contrast to most putative antigenic variants, oseltamivir-resistant variants rapidly increased to high frequencies in the virus population. Importantly, the majority of putative antigenic variants and oseltamivir-resistant variants were first detectable four or more days after onset of symptoms or start of treatment, respectively. Our observations demonstrate that de novo variants emerge, and may be positively selected, during the course of infection. Additionally, based on the 4–7 days post-treatment delay in emergence of oseltamivir-resistant variants in six out of the eight individuals with such variants, we find that limiting sample collection for routine surveillance and diagnostic testing to early timepoints after onset of symptoms can potentially preclude detection of emerging, positively selected variants.


mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Jin Gao ◽  
Laura Couzens ◽  
David F. Burke ◽  
Hongquan Wan ◽  
Patrick Wilson ◽  
...  

ABSTRACTThe effectiveness of influenza vaccines against circulating A(H1N1)pdm09 viruses was modest for several seasons despite the absence of antigenic drift of hemagglutinin (HA), the primary vaccine component. Since antibodies against HA and neuraminidase (NA) contribute independently to protection against disease, antigenic changes in NA may allow A(H1N1)pdm09 viruses to escape from vaccine-induced immunity. In this study, analysis of the specificities of human NA-specific monoclonal antibodies identified antigenic sites that have changed over time. The impact of these differences onin vitroinhibition of enzyme activity was not evident for polyclonal antisera until viruses emerged in 2013 without a predicted glycosylation site at amino acid 386 in NA. Phylogenetic and antigenic cartography demonstrated significant antigenic changes that in most cases aligned with genetic differences. Typical of NA drift, the antigenic difference is observed in one direction, with antibodies against conserved antigenic domains in A/California/7/2009 (CA/09) continuing to inhibit NA of recent A(H1N1)pdm09 viruses reasonably well. However, ferret CA/09-specific antiserum that inhibited the NA of A/Michigan/45/2015 (MI/15) very wellin vitro, protected mice against lethal MI/15 infection poorly. These data show that antiserum against the homologous antigen is most effective and suggest the antigenic properties of NA should not be overlooked when selecting viruses for vaccine production.IMPORTANCEThe effectiveness of seasonal influenza vaccines against circulating A(H1N1)pdm09 viruses has been modest in recent years, despite the absence of antigenic drift of HA, the primary vaccine component. Human monoclonal antibodies identified antigenic sites in NA that changed early after the new pandemic virus emerged. The reactivity of ferret antisera demonstrated antigenic drift of A(H1N1)pdm09 NA from 2013 onward. Passive transfer of serum raised against A/California/7/2009 was less effective than ferret serum against the homologous virus in protecting mice against a virus with the NA of more recent virus, A/Michigan/45/2015. Given the long-standing observation that NA-inhibiting antibodies are associated with resistance against disease in humans, these data demonstrate the importance of evaluating NA drift and suggest that vaccine effectiveness might be improved by selecting viruses for vaccine production that have NAs antigenically similar to those of circulating influenza viruses.


2019 ◽  
Vol 94 (6) ◽  
Author(s):  
Yu Qiu ◽  
Svetlana Stegalkina ◽  
Jianxin Zhang ◽  
Ekaterina Boudanova ◽  
Anna Park ◽  
...  

ABSTRACT The discovery of potent and broadly protective influenza virus epitopes could lead to improved vaccines that are resistant to antigenic drift. Here, we describe human antibody C585, isolated from a vaccinee with remarkable serological breadth as measured by hemagglutinin inhibition (HAI). C585 binds and neutralizes multiple H3N2 strains isolated between 1968 and 2016, including strains that emerged up to 4 years after B cells were isolated from the vaccinated donor. The crystal structure of C585 Fab in complex with the HA from A/Switzerland/9715293/2013 (H3N2) shows that the antibody binds to a novel and well-conserved epitope on the globular head of H3 HA and that it differs from other antibodies not only in its epitope but in its binding geometry and hypermutated framework 3 region, thereby explaining its breadth and ability to mediate hemagglutination inhibition across decades of H3N2 strains. The existence of epitopes such as the one elucidated by C585 has implications for rational vaccine design. IMPORTANCE Influenza viruses escape immunity through continuous antigenic changes that occur predominantly on the viral hemagglutinin (HA). Induction of broadly neutralizing antibodies (bnAbs) targeting conserved epitopes following vaccination is a goal of universal influenza vaccines and advantageous in protecting hosts against virus evolution and antigenic drift. To date, most of the discovered bnAbs bind either to conserved sites in the stem region or to the sialic acid-binding pocket. Generally, antibodies targeting the stem region offer broader breadth with low potency, while antibodies targeting the sialic acid-binding pocket cover narrower breadth but usually have higher potency. In this study, we identified a novel neutralizing epitope in the head region recognized by a broadly neutralizing human antibody against a broad range of H3N2 with high potency. This epitope may provide insights for future universal vaccine design.


1999 ◽  
Vol 44 (suppl_2) ◽  
pp. 3-9 ◽  
Author(s):  
Maria C. Zambon

Abstract Influenza A, B and C all have a segmented genome, although only certain influenza A subtypes and influenza B cause severe disease in humans. The two major proteins of influenza are the surface glycoproteins—haemagglutinin (HA) and neuraminidase (NA). HA is the major antigen for neutralizing antibodies and is involved in the binding of virus particles to receptors on host cells. Pandemics are a result of novel virus subtypes of influenza A, created by reassortment of the segmented genome (antigenic shift), whereas annual epidemics are a result of evolution of the surface antigens of influenza A and B virus (antigenic drift). The rapid evolution of influenza viruses highlights the importance of surveillance in identifying novel circulating strains. Infectivity of influenza depends on the cleavage of HA by specific host proteases, whereas NA is involved in the release of progeny virions from the cell surface and prevents clumping of newly formed virus. In birds, the natural hosts of influenza, the virus causes gastrointestinal infection and is transmitted via the faeco-oral route. Virulent avian influenza strains, which cause systemic disease, have an HA that is cleaved by proteases present in all cells of the body, rather than by proteases restricted to the intestinal tract. In mammals, replication of influenza subtypes appears restricted to respiratory epithelial cells. Most symptoms and complications, therefore, involve the respiratory tract. However, systemic complications are sometimes observed and other viral genes besides the HA, including the NA, may be involved in determination of virulence of influenza strains in mammals.


Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 434 ◽  
Author(s):  
Christopher E. Lopez ◽  
Kevin L. Legge

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.


1950 ◽  
Vol 91 (1) ◽  
pp. 65-86 ◽  
Author(s):  
Duard L. Walker ◽  
Frank L. Horsfall

There is an exponential linear relationship between the quantity of influenza virus neutralized and the quantity of immune serum employed in in ovo neutralization. The slope of the neutralization line is extremely steep. The concentration of neutralizing antibody can be measured with considerable precision in ovo if the constant virus-varying serum technique is utilized. The amounts of hemagglutination-inhibiting and neutralizing antibodies which are absorbed by a given quantity of influenza virus (PR8) were found to be predictable and the degree of reactivity of these two antibodies was shown to be directly related to the extent of immunization. It was demonstrated that there are marked discrepancies in correlation between antibody titers obtained by in vitro hemagglutination-inhibition and in vivo neutralization techniques and that neutralizing antibody is preferentially absorbed by a given quantity of virus. Inasmuch as the results were found not to be attributable to peculiarities of the techniques employed, it appears that the antibodies measured by hemagglutination-inhibition in vitro and by neutralization in vivo are not identical.


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