scholarly journals Dimerization of Dengue Virus E Subunits Impacts Antibody Function and Domain Focus

2020 ◽  
Vol 94 (18) ◽  
Author(s):  
Ashlie Thomas ◽  
Devina J. Thiono ◽  
Stephan T. Kudlacek ◽  
John Forsberg ◽  
Lakshmanane Premkumar ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Virus Vaccine ◽  
Neutralizing Antibodies ◽  
Quaternary Structure ◽  
Protein Structures ◽  
Protein Subunit ◽  
Subunit Vaccines ◽  
E Protein ◽  
Vaccine Antigens ◽  
Viral Surface

ABSTRACT Dengue virus (DENV) is responsible for the most prevalent and significant arthropod-borne viral infection of humans. The leading DENV vaccines are based on tetravalent live-attenuated virus platforms. In practice, it has been challenging to induce balanced and effective responses to each of the four DENV serotypes because of differences in the replication efficiency and immunogenicity of individual vaccine components. Unlike live vaccines, tetravalent DENV envelope (E) protein subunit vaccines are likely to stimulate balanced immune responses, because immunogenicity is replication independent. However, E protein subunit vaccines have historically performed poorly, in part because the antigens utilized were mainly monomers that did not display quaternary-structure epitopes found on E dimers and higher-order structures that form the viral envelope. In this study, we compared the immunogenicity of DENV2 E homodimers and DENV2 E monomers. The stabilized DENV2 homodimers, but not monomers, were efficiently recognized by virus-specific and flavivirus cross-reactive potently neutralizing antibodies that have been mapped to quaternary-structure epitopes displayed on the viral surface. In mice, the dimers stimulated 3-fold-higher levels of virus-specific neutralizing IgG that recognized epitopes different from those recognized by lower-level neutralizing antibodies induced by monomers. The dimer induced a stronger E domain I (EDI)- and EDII-targeted response, while the monomer antigens stimulated an EDIII epitope response and induced fusion loop epitope antibodies that are known to facilitate antibody-dependent enhancement (ADE). This study shows that DENV E subunit antigens that have been designed to mimic the structural organization of the viral surface are better vaccine antigens than E protein monomers. IMPORTANCE Dengue virus vaccine development is particularly challenging because vaccines have to provide protection against four different dengue virus stereotypes. The leading dengue virus vaccine candidates in clinical testing are all based on live-virus vaccine platforms and struggle to induce balanced immunity. Envelope subunit antigens have the potential to overcome these limitations but have historically performed poorly as vaccine antigens, because the versions tested previously were presented as monomers and not in their natural dimer configuration. This study shows that the authentic presentation of DENV2 E-based subunits has a strong impact on antibody responses, underscoring the importance of mimicking the complex protein structures that are found on DENV particle surfaces when designing subunit vaccines.

scholarly journals Oligomeric state of the ZIKV E protein defines protective immune responses

2019 ◽  
Author(s):  
Stefan W. Metz ◽  
Ashlie Thomas ◽  
Alex Brackbill ◽  
John Forsberg ◽  
Michael J. Miley ◽  
...  
Keyword(s):  
Mouse Model ◽  
Neutralizing Antibodies ◽  
Quaternary Structure ◽  
Poor Performance ◽  
Protein Subunit ◽  
Oligomeric State ◽  
Subunit Vaccines ◽  
Safety Issues ◽  
E Protein ◽  
Domain Iii

AbstractThe current leading Zika vaccine candidates in clinical testing are based on live or killed virus platforms, which have safety issues, especially in pregnant women. Zika subunit vaccines, however, have shown poor performance in preclinical studies. We hypothesized that Zika Envelope (E) protein subunit vaccines have performed poorly because the antigens tested have been recombinant E monomers that do not display critical quaternary structure epitopes present on Zika E protein homodimers that cover the surface of the virus. To test this hypothesis, we engineered and produced stable recombinant E protein homodimers. Unlike the E monomer, the dimer was recognized by strongly neutralizing monoclonal antibodies isolated from Zika-immune individuals. In a mouse model of vaccination, the dimeric antigen stimulated strongly neutralizing antibodies that targeted epitopes that were similar to epitopes recognized by human antibodies following natural Zika virus infection. In contrast, the monomer antigen stimulated lower levels of neutralizing antibodies directed to simple epitopes on domain III of E protein. In a mouse model of ZIKV challenge, only E dimer antigen stimulated protective antibodies, not the monomer. These results highlight the importance of mimicking the highly structured flavivirus surface when designing subunit vaccines. The flavivirus field has a long history of using E monomers as vaccine antigens with limited success. These results are applicable to developing second generation subunit vaccines against Zika as well as other medically important flaviviruses such as dengue and yellow fever viruses.

scholarly journals Oligomeric state of the ZIKV E protein defines protective immune responses

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Stefan W. Metz ◽  
Ashlie Thomas ◽  
Alex Brackbill ◽  
John Forsberg ◽  
Michael J. Miley ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Quaternary Structure ◽  
Poor Performance ◽  
Oligomeric State ◽  
Subunit Vaccines ◽  
Safety Issues ◽  
E Protein ◽  
Protective Antibodies ◽  
Low Levels ◽  
Domain Iii

Abstract The current leading Zika vaccine candidates in clinical testing are based on live or killed virus platforms, which have safety issues, especially in pregnant women. Zika subunit vaccines, however, have shown poor performance in preclinical studies, most likely because the antigens tested do not display critical quaternary structure epitopes present on Zika E protein homodimers that cover the surface of the virus. Here, we produce stable recombinant E protein homodimers that are recognized by strongly neutralizing Zika specific monoclonal antibodies. In mice, the dimeric antigen stimulate strongly neutralizing antibodies that target epitopes that are similar to epitopes recognized by human antibodies following natural Zika virus infection. The monomer antigen stimulates low levels of E-domain III targeting neutralizing antibodies. In a Zika challenge model, only E dimer antigen stimulates protective antibodies, not the monomer. These results highlight the importance of mimicking the highly structured flavivirus surface when designing subunit vaccines.

scholarly journals Disassembly of HIV envelope glycoprotein trimer immunogens is driven by antibodies elicited via immunization

2021 ◽  
Author(s):  
Hannah L. Turner ◽  
Raiees Andrabi ◽  
Christopher A. Cottrell ◽  
Sara T. Richey ◽  
Ge Song ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Epitope Mapping ◽  
Antibody Responses ◽  
Viral Fusion ◽  
Protein Subunit ◽  
Subunit Vaccines ◽  
Hiv Envelope ◽  
Viral Surface

AbstractRationally designed protein subunit vaccines are being developed for a variety of viruses including influenza, RSV, SARS-CoV-2 and HIV. These vaccines are based on stabilized versions of the primary targets of neutralizing antibodies on the viral surface, namely viral fusion glycoproteins. While these immunogens display the epitopes of potent neutralizing antibodies, they also present epitopes recognized by non or weakly neutralizing (“off-target”) antibodies. Using our recently developed electron microscopy epitope mapping approach, we have uncovered a phenomenon wherein off-target antibodies elicited by HIV trimer subunit vaccines cause the otherwise highly stabilized trimeric proteins to degrade into cognate protomers. Further, we show that these protomers expose an expanded suite of off-target epitopes, normally occluded inside the prefusion conformation of trimer, that subsequently elicit further off-target antibody responses. Our study provides critical insights for further improvement of HIV subunit trimer vaccines for future rounds of the iterative vaccine design process.

scholarly journals Disassembly of HIV envelope glycoprotein trimer immunogens is driven by antibodies elicited via immunization

2021 ◽  
Vol 7 (31) ◽  
pp. eabh2791
Author(s):  
Hannah L. Turner ◽  
Raiees Andrabi ◽  
Christopher A. Cottrell ◽  
Sara T. Richey ◽  
Ge Song ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Envelope Glycoprotein ◽  
Neutralizing Antibodies ◽  
Epitope Mapping ◽  
Antibody Responses ◽  
Viral Fusion ◽  
Protein Subunit ◽  
Subunit Vaccines ◽  
Hiv Envelope ◽  
Viral Surface

Rationally designed protein subunit vaccines are being developed for a variety of viruses including influenza, RSV, SARS-CoV-2, and HIV. These vaccines are based on stabilized versions of the primary targets of neutralizing antibodies on the viral surface, namely, viral fusion glycoproteins. While these immunogens display the epitopes of potent neutralizing antibodies, they also present epitopes recognized by non-neutralizing or weakly neutralizing (“off-target”) antibodies. Using our recently developed electron microscopy polyclonal epitope mapping approach, we have uncovered a phenomenon wherein off-target antibodies elicited by HIV trimer subunit vaccines cause the otherwise highly stabilized trimeric proteins to degrade into cognate protomers. Further, we show that these protomers expose an expanded suite of off-target epitopes, normally occluded inside the prefusion conformation of trimer, that subsequently elicit further off-target antibody responses. Our study provides critical insights for further improvement of HIV subunit trimer vaccines for future rounds of the iterative vaccine design process.

scholarly journals Overview of Plant-Derived Vaccine Antigens: Dengue Virus

2011 ◽  
Vol 14 (3) ◽  
pp. 400 ◽  
Author(s):  
Ravindra B Malabadi ◽  
Advaita Ganguly ◽  
Jaime A Teixeira da Silva ◽  
Archana Parashar ◽  
Mavanur R Suresh ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Low Cost ◽  
Current Status ◽  
Human Immune Deficiency Virus ◽  
Dengue Vaccine ◽  
New Methods ◽  
Vaccine Antigens

ABSTRACT - This review highlights the advantages and current status of plant-derived vaccine development with special reference to the dengue virus. There are numerous problems involved in dengue vaccine development, and there is no vaccine against all four dengue serotypes. Dengue vaccine development using traditional approaches has not been satisfactory in terms of inducing neutralizing antibodies. Recently, these issues were addressed by showing a very good response to inducing neutralizing antibodies by plant-derived dengue vaccine antigens. This indicates the feasibility of using plant-derived vaccine antigens as a low-cost method to combat dengue and other infectious diseases. The application of new methods and strategies such as dendritic cell targeting in cancer therapy, severe acute respiratory syndrome, tuberculosis, human immune deficiency virus, and malaria might play an important role. These new methods are more efficient than traditional protocols. It is expected that in the near future, plant-derived vaccine antigens or antibodies will play an important role in the control of human infectious diseases. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

scholarly journals Biomaterials and oxygen join forces to shape the immune response and boost SARS-CoV-2 vaccines

2020 ◽  
Author(s):  
Thibault Colombani ◽  
Loek Eggermont ◽  
Zachary Rogers ◽  
Lindsay McKay ◽  
Laura Avena ◽  
...  
Keyword(s):  
Immune Response ◽  
Neutralizing Antibodies ◽  
High Titer ◽  
Full Potential ◽  
Protein Subunit ◽  
Subunit Vaccines ◽  
Health Crisis ◽  
Th2 Immune Response ◽  
Protective Antibodies ◽  
Advanced Biomaterials

Abstract Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to an unprecedented global health crisis, resulting in a critical need for effective vaccines that generate protective antibodies. Protein subunit vaccines represent a promising approach but often lack the immunogenicity required for strong immune stimulation. To overcome this challenge, we first demonstrate that advanced biomaterials boost effectiveness of SARS-CoV-2 protein subunit vaccines. Additionally, we report that oxygen is a powerful immunological co-adjuvant, a game-changer in the field for unlocking the full potential of vaccines. Mice immunized with oxygen-generating cryogel vaccines exhibited a robust and balanced Th1 and Th2 immune response, leading to sustained and high titer production of neutralizing antibodies against SARS-CoV-2. Our data indicate that this platform is a revolutionary technology with the potential to reinforce any vaccine.

scholarly journals Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment immunogen

2020 ◽  
Author(s):  
Sameer Kumar Malladi ◽  
Randhir Singh ◽  
Suman Pandey ◽  
Savitha Gayathri ◽  
Kawkab Kanjo ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Viral Vectors ◽  
Mammalian Cell Culture ◽  
Geometric Mean ◽  
High Yield ◽  
Great Promise ◽  
Protein Subunit ◽  
Protein Fragment ◽  
Subunit Vaccines ◽  
Major Impediment

AbstractVirtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Several use viral vectors or mRNA. In contrast to protein subunit vaccines, there is limited manufacturing expertise for these novel, nucleic acid based modalities, especially in the developing world. Neutralizing antibodies, the clearest known correlate of protection against SARS-CoV-2, are primarily directed against the Receptor Binding Domain (RBD) of the viral spike protein. We describe a monomeric, glycan engineered RBD protein fragment that is expressed at a purified yield of 214mg/L in unoptimized, mammalian cell culture and in contrast to a stabilized spike ectodomain, is tolerant of exposure to temperatures as high as 100°C when lyophilized, upto 70°C in solution and stable for over four weeks at 37°C. In prime:boost guinea pig immunizations, when formulated with the MF59 like adjuvant AddaVax™, the RBD derivative elicited neutralizing antibodies with an endpoint geometric mean titer of ~415 against replicative virus, comparing favourably with several vaccine formulations currently in the clinic. These features of high yield, extreme thermotolerance and satisfactory immunogenicity suggest that such RBD subunit vaccine formulations hold great promise to combat COVID-19.

scholarly journals Design of a highly thermotolerant, immunogenic SARS-CoV-2 spike fragment

2020 ◽  
pp. jbc.RA120.016284
Author(s):  
Sameer Kumar Malladi ◽  
Randhir Singh ◽  
Suman Pandey ◽  
Savitha Gayathri ◽  
Kawkab Kanjo ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Viral Vectors ◽  
Mammalian Cell Culture ◽  
Geometric Mean ◽  
High Yield ◽  
Great Promise ◽  
Protein Subunit ◽  
Protein Fragment ◽  
Subunit Vaccines ◽  
Major Impediment

Virtually all SARS-CoV-2 vaccines currently in clinical testing are stored in a refrigerated or frozen state prior to use. This is a major impediment to deployment in resource-poor settings. Furthermore, several of them use viral vectors or mRNA. In contrast to protein subunit vaccines, there is limited manufacturing expertise for these nucleic acid-based modalities, especially in the developing world. Neutralizing antibodies, the clearest known correlate of protection against SARS-CoV-2, are primarily directed against the Receptor Binding Domain (RBD) of the viral spike protein, suggesting that a suitable RBD construct might serve as a more accessible vaccine ingredient. We describe a monomeric, glycan engineered RBD protein fragment that is expressed at a purified yield of 214 mg/L in unoptimized, mammalian cell culture and, in contrast to a stabilized spike ectodomain, is tolerant of exposure to temperatures as high as 100 °C when lyophilized, up to 70 °C in solution and stable for over four weeks at 37 °C. In prime:boost guinea pig immunizations, when formulated with the MF59-like adjuvant AddaVax™, the RBD derivative elicited neutralizing antibodies with an endpoint geometric mean titer of ~415 against replicative virus, comparing favourably with several vaccine formulations currently in the clinic. These features of high yield, extreme thermotolerance and satisfactory immunogenicity suggest that such RBD subunit vaccine formulations hold great promise to combat COVID-19.

scholarly journals High-Avidity and Potently Neutralizing Cross-Reactive Human Monoclonal Antibodies Derived from Secondary Dengue Virus Infection

2013 ◽  
Vol 87 (23) ◽  
pp. 12562-12575 ◽  
Author(s):  
Wen-Yang Tsai ◽  
Chih-Yun Lai ◽  
Yi-Chieh Wu ◽  
Hong-En Lin ◽  
Carolyn Edwards ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Dengue Virus ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Secondary Infection ◽  
Significant Proportion ◽  
Denv Infection ◽  
Protein Domain ◽  
High Avidity ◽  
E Protein

The envelope (E) protein of dengue virus (DENV) is the major target of neutralizing antibodies (Abs) and vaccine development. Previous studies of human dengue-immune sera reported that a significant proportion of anti-E Abs, known as group-reactive (GR) Abs, were cross-reactive to all four DENV serotypes and to one or more other flaviviruses. Based on studies of mouse anti-E monoclonal antibodies (MAbs), GR MAbs were nonneutralizing or weakly neutralizing compared with type-specific MAbs; a GR response was thus not regarded as important for vaccine strategy. We investigated the epitopes, binding avidities, and neutralization potencies of 32 human GR anti-E MAbs. In addition to fusion loop (FL) residues in E protein domain II, human GR MAbs recognized an epitope involving both FL and bc loop residues in domain II. The neutralization potencies and binding avidities of GR MAbs derived from secondary DENV infection were stronger than those derived from primary infection. GR MAbs derived from primary DENV infection primarily blocked attachment, whereas those derived from secondary infection blocked DENV postattachment. Analysis of the repertoire of anti-E MAbs derived from patients with primary DENV infection revealed that the majority were GR, low-avidity, and weakly neutralizing MAbs, whereas those from secondary infection were primarily GR, high-avidity, and potently neutralizing MAbs. Our findings suggest that the weakly neutralizing GR anti-E Abs generated from primary DENV infection become potently neutralizing MAbs against the four serotypes after secondary infection. The observation that the dengue immune status of the host affects the quality of the cross-reactive Abs generated has implications for new strategies for DENV vaccination.

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