Broadly-neutralizing antibodies that bind to the influenza hemagglutinin stalk domain enhance the effectiveness of neuraminidase inhibitors via Fc-mediated effector functions

2021 ◽  
Author(s):  
Ali Zhang ◽  
Hanu Chaudhari ◽  
Yonathan Agung ◽  
Michael D'Agostino ◽  
Jann Ang ◽  
...  

The conserved hemagglutinin stalk domain is an attractive target for broadly effective antibody-based therapeutics and next generation universal influenza vaccines. Protection provided by hemagglutinin stalk binding antibodies is principally mediated through activation of immune effector cells. Titers of stalk-binding antibodies are highly variable on an individual level, and tend to increase with age as a result of increasing exposures to influenza virus. In our study, we show that stalk-binding antibodies cooperate with neuraminidase inhibitors to protect against influenza virus infection in an Fc-dependent manner. These data suggest that the effectiveness of neuraminidase inhibitors is likely influenced by an individual's titers of stalk-binding antibodies, and that neuraminidase inhibitors may enhance the effectiveness of future stalk-binding monoclonal antibody-based treatments.

Vaccines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 40
Author(s):  
Wen-Chun Liu ◽  
Raffael Nachbagauer ◽  
Daniel Stadlbauer ◽  
Shirin Strohmeier ◽  
Alicia Solórzano ◽  
...  

Epidemic or pandemic influenza can annually cause significant morbidity and mortality in humans. We developed novel chimeric hemagglutinin (cHA)-based universal influenza virus vaccines, which contain a conserved HA stalk domain from a 2009 pandemic H1N1 (pH1N1) strain combined with globular head domains from avian influenza A viruses. Our previous reports demonstrated that prime-boost sequential immunizations induced robust antibody responses directed toward the conserved HA stalk domain in ferrets. Herein, we further followed vaccinated animals for one year to compare the efficacy and durability of these vaccines in the preclinical ferret model of influenza. Although all cHA-based immunization regimens induced durable HA stalk-specific and heterosubtypic antibody responses in ferrets, sequential immunization with live-attenuated influenza virus vaccines (LAIV-LAIV) conferred the best protection against upper respiratory tract infection by a pH1N1 influenza A virus. The findings from this study suggest that our sequential immunization strategy for a cHA-based universal influenza virus vaccine provides durable protective humoral and cellular immunity against influenza virus infection.


2018 ◽  
Vol 92 (12) ◽  
Author(s):  
Ina Fetzer ◽  
Matthew R. Gardner ◽  
Meredith E. Davis-Gardner ◽  
Neha R. Prasad ◽  
Barnett Alfant ◽  
...  

ABSTRACTThe human immunodeficiency virus type 1 (HIV-1) entry inhibitor eCD4-Ig is a fusion of CD4-Ig and a coreceptor-mimetic peptide. eCD4-Ig is markedly more potent than CD4-Ig, with neutralization efficiencies approaching those of HIV-1 broadly neutralizing antibodies (bNAbs). However, unlike bNAbs, eCD4-Ig neutralized all HIV-1, HIV-2, and simian immunodeficiency virus (SIV) isolates that it has been tested against, suggesting that it may be useful in clinical settings, where antibody escape is a concern. Here, we characterize three new eCD4-Ig variants, each with a different architecture and each utilizing D1.22, a stabilized form of CD4 domain 1. These variants were 10- to 20-fold more potent than our original eCD4-Ig variant, with a construct bearing four D1.22 domains (eD1.22-HL-Ig) exhibiting the greatest potency. However, this variant mediated less efficient antibody-dependent cell-mediated cytotoxicity (ADCC) activity than eCD4-Ig itself or several other eCD4-Ig variants, including the smallest variant (eD1.22-Ig). A variant with the same architecture as the original eCD4-Ig (eD1.22-D2-Ig) showed modestly higher thermal stability and best prevented the promotion of infection of CCR5-positive, CD4-negative cells. All three variants, and eCD4-Ig itself, mediated more efficient shedding of the HIV-1 envelope glycoprotein gp120 than did CD4-Ig. Finally, we show that only three D1.22 mutations contributed to the potency of eD1.22-D2-Ig and that introduction of these changes into eCD4-Ig resulted in a variant 9-fold more potent than eCD4-Ig and 2-fold more potent than eD1.22-D2-Ig. These studies will assist in developing eCD4-Ig variants with properties optimized for prophylaxis, therapy, and cure applications.IMPORTANCEHIV-1 bNAbs have properties different from those of antiretroviral compounds. Specifically, antibodies can enlist immune effector cells to eliminate infected cells, whereas antiretroviral compounds simply interfere with various steps in the viral life cycle. Unfortunately, HIV-1 is adept at evading antibody recognition, limiting the utility of antibodies as a treatment for HIV-1 infection or as part of an effort to eradicate latently infected cells. eCD4-Ig is an antibody-like entry inhibitor that closely mimics HIV-1's obligate receptors. eCD4-Ig appears to be qualitatively different from antibodies, since it neutralizes all HIV-1, HIV-2, and SIV isolates. Here, we characterize three new structurally distinct eCD4-Ig variants and show that each excels in a key property useful to prevent, treat, or cure an HIV-1 infection. For example, one variant neutralized HIV-1 most efficiently, while others best enlisted natural killer cells to eliminate infected cells. These observations will help generate eCD4-Ig variants optimized for different clinical applications.


Vaccines ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 768
Author(s):  
Hirotaka Hayashi ◽  
Norikazu Isoda ◽  
Enkhbold Bazarragchaa ◽  
Naoki Nomura ◽  
Keita Matsuno ◽  
...  

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.


2010 ◽  
Vol 30 (6) ◽  
pp. 439-449 ◽  
Author(s):  
Ido D. Weiss ◽  
Ori Wald ◽  
Hanna Wald ◽  
Katia Beider ◽  
Michal Abraham ◽  
...  

2021 ◽  
Author(s):  
yuqi Wang ◽  
Yanyan Wang ◽  
Hong Cao

Abstract Background: Influenza virus infection with seasonal or occasional but devastating morbidity and mortality, is a severe threat to public health. The frequent emergence of resistant viral strains limited application of current antivirals and posing an urgent need for novel antiviral therapies. Natural products offered a broad prospect in the screening and development of new influenza inhibitors.Methods: In this research, a high-throughput antiviral screening for 891 natural products was performed based on a recombinant reporter influenza A virus. According to the cytotoxicity assay and dose-response relationship, alloprogesterone (ALLO), as the positive hit was selected, and verified by viral titer reduction assay and immunofluorescence using a wild-type virus. Followingly, we explored its antiviral potency of counteracting with IAV and IBV, and preliminary investigated the mechanism of ALLO through time-of-addition assay and mini-replicon system.Results: Under the criteria of 80% inhibition and 70% cell viability, ALLO was screened out and confirmed antiviral activity in varied cells. The inhibitory effect of ALLO against influenza virus with a dose-dependent manner and significantly reduced viral yield of five different influenza viruses in the presence of 40 µM ALLO, including oseltamivir-resistant virus. Moreover, ALLO exhibited no influence on IAV entry or release during the viral replication cycle, but obviously interfered with the genome replication regarding post-infection 2 hrs to 6 hrs, which is consistent with the evidence of decreased polymerase activity.Conclusions: In summary, we firstly identified a new pharmacological activity of ALLO, as a broad spectrum inhibitor for treatment influenza infections, targeting viral replication stage and possessing great value of further development.


Science ◽  
2018 ◽  
Vol 362 (6414) ◽  
pp. 598-602 ◽  
Author(s):  
Nick S. Laursen ◽  
Robert H. E. Friesen ◽  
Xueyong Zhu ◽  
Mandy Jongeneelen ◽  
Sven Blokland ◽  
...  

Broadly neutralizing antibodies against highly variable pathogens have stimulated the design of vaccines and therapeutics. We report the use of diverse camelid single-domain antibodies to influenza virus hemagglutinin to generate multidomain antibodies with impressive breadth and potency. Multidomain antibody MD3606 protects mice against influenza A and B infection when administered intravenously or expressed locally from a recombinant adeno-associated virus vector. Crystal and single-particle electron microscopy structures of these antibodies with hemagglutinins from influenza A and B viruses reveal binding to highly conserved epitopes. Collectively, our findings demonstrate that multidomain antibodies targeting multiple epitopes exhibit enhanced virus cross-reactivity and potency. In combination with adeno-associated virus–mediated gene delivery, they may provide an effective strategy to prevent infection with influenza virus and other highly variable pathogens.


Vaccines ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 113 ◽  
Author(s):  
Choi ◽  
Christopoulou ◽  
Saelens ◽  
García-Sastre ◽  
Schotsaert

Background: Influenza virus infection predisposes to secondary bacterial pneumonia. Currently licensed influenza vaccines aim at the induction of neutralizing antibodies and are less effective if the induction of neutralizing antibodies is low and/or the influenza virus changes its antigenic surface. We investigated the effect of suboptimal vaccination on the outcome of post-influenza bacterial superinfection. Methods: We established a mouse vaccination model that allows control of disease severity after influenza virus infection despite inefficient induction of virus-neutralizing antibody titers by vaccination. We investigated the effect of vaccination on virus-induced host immune responses and on the outcome of superinfection with Staphylococcus aureus. Results: Vaccination with trivalent inactivated virus vaccine (TIV) reduced morbidity after influenza A virus infection but did not prevent virus replication completely. Despite the poor induction of influenza-specific antibodies, TIV protected from mortality after bacterial superinfection. Vaccination limited loss of alveolar macrophages and reduced levels of infiltrating pulmonary monocytes after influenza virus infection. Interestingly, TIV vaccination resulted in enhanced levels of eosinophils after influenza virus infection and recruitment of neutrophils in both lungs and mediastinal lymph nodes after bacterial superinfection. Conclusion: These observations highlight the importance of disease modulation by influenza vaccination, even when suboptimal, and suggest that influenza vaccination is still beneficial to protect during bacterial superinfection in the absence of complete virus neutralization.


mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Raffael Nachbagauer ◽  
Angela Choi ◽  
Ruvim Izikson ◽  
Manon M. Cox ◽  
Peter Palese ◽  
...  

ABSTRACT Influenza remains a major global health burden. Seasonal vaccines offer protection but can be rendered less effective when the virus undergoes extensive antigenic drift. Antibodies that target the highly conserved hemagglutinin stalk can protect against drifted viruses, and vaccine constructs designed to induce such antibodies form the basis for a universal influenza virus vaccine approach. In this study, we analyzed baseline and postvaccination serum samples of children (6 to 59 months), adults (18 to 49 years), and elderly individuals (≥65 years) who participated in clinical trials with a recombinant hemagglutinin-based vaccine. We found that baseline IgG and IgA antibodies against the H1 stalk domain correlated with the ages of patients. Children generally had very low baseline titers and did not respond well to the vaccine in terms of making stalk-specific antibodies. Adults showed the highest induction of stalk-specific antibodies, but the elderly had the highest absolute antibody titers against the stalk. Importantly, the stalk antibodies measured by enzyme-linked immunosorbent assay (ELISA) showed neutralizing activity in neutralization assays and protected mice in a passive-transfer model in a stalk titer-dependent manner. Finally, we found similar patterns of stalk-specific antibodies directed against the H3 and influenza B virus hemagglutinins, albeit at lower levels than those measured against the H1 stalk. The relatively high levels of stalk-specific antibodies in the elderly patients may explain the previously reported low influenza virus infection rates in this age group. (This study has been registered at ClinicalTrials.gov under registration no. NCT00336453, NCT00539981, and NCT00395174.) IMPORTANCE The present study provides evidence that titers of broadly neutralizing hemagglutinin stalk-reactive antibodies increase with age, possibly due to repeated exposure to divergent influenza viruses. These relatively high levels of antistalk titers may be responsible for lower circulation rates of influenza viruses in older individuals. Our findings suggest that the level of antistalk antibodies is a good surrogate marker for protection against influenza virus infection. In addition, the levels of antistalk antibodies might determine the breadth of protection against different drifted strains.


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