scholarly journals An mRNA vaccine against SARS-CoV-2: Lyophilized, liposome-based vaccine candidate EG-COVID induces high levels of virus neutralizing antibodies

2021 ◽  
Author(s):  
H. Christian Hong ◽  
Kwang Sung Kim ◽  
Shin Ae Park ◽  
Min Jeong Chun ◽  
Eun Young Hong ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vaccine Candidate ◽  
Vero Cells ◽  
Vaccine Platform ◽  
New Era ◽  
European Variant ◽  
Cellular Immune ◽  
And Storage

AbstractIn addition to the traditional method of vaccine development, the mRNA coronavirus vaccine, which is attractive as a challenging vaccination, recently opened a new era in vaccinology. Here we describe the EG-COVID which is a novel liposome-based mRNA candidate vaccine that encodes the spike (S) protein of SARS-CoV-2 with 2P-3Q substitution in European variant. We developed the mRNA vaccine platform that can be lyophilized using liposome-based technology. Intramuscular injection of the EG-COVID elicited robust humoral and cellular immune response to SARS-CoV-2. Furthermore, sera obtained from mice successfully inhibited SARS-CoV-2 viral infection into Vero cells. We developed EG-COVID and found it to be effective based on in vitro data, and we plan to initiate a clinical trial soon. Since EG-COVID is a lyophilized mRNA vaccine that is convenient for transportation and storage, accessibility to vaccines will be significantly improved.

scholarly journals Cellular and Humoral Immunogenicity of a Candidate DNA Vaccine Expressing SARS-CoV-2 Spike Subunit 1

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 852
Author(s):  
Khalid A. Alluhaybi ◽  
Rahaf H. Alharbi ◽  
Rowa Y. Alhabbab ◽  
Najwa D. Aljehani ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Immune Responses ◽  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Specific Igg ◽  
Cellular Immune ◽  
Different Doses

The urgent need for effective, safe and equitably accessible vaccines to tackle the ongoing spread of COVID-19 led researchers to generate vaccine candidates targeting varieties of immunogens of SARS-CoV-2. Because of its crucial role in mediating binding and entry to host cell and its proven safety profile, the subunit 1 (S1) of the spike protein represents an attractive immunogen for vaccine development. Here, we developed and assessed the immunogenicity of a DNA vaccine encoding the SARS-CoV-2 S1. Following in vitro confirmation and characterization, the humoral and cellular immune responses of our vaccine candidate (pVAX-S1) was evaluated in BALB/c mice using two different doses, 25 µg and 50 µg. Our data showed high levels of SARS-CoV-2 specific IgG and neutralizing antibodies in mice immunized with three doses of pVAX-S1. Analysis of the induced IgG subclasses showed a Th1-polarized immune response, as demonstrated by the significant elevation of spike-specific IgG2a and IgG2b, compared to IgG1. Furthermore, we found that the immunization of mice with three doses of 50 µg of pVAX-S1 could elicit significant memory CD4+ and CD8+ T cell responses. Taken together, our data indicate that pVAX-S1 is immunogenic and safe in mice and is worthy of further preclinical and clinical evaluation.

scholarly journals Development of a Multi-Antigenic SARS-CoV-2 Vaccine Using a Synthetic Poxvirus Platform

2020 ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

Abstract Modified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. Mice immunized with these sMVA vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

scholarly journals Development of a multi-antigenic SARS-CoV-2 vaccine candidate using a synthetic poxvirus platform

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu H. Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

AbstractModified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We demonstrate the construction of a vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we use this vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. We show that mice immunized with these sMVA vectors develop robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

scholarly journals Development of a Synthetic Poxvirus-Based SARS-CoV-2 Vaccine

2020 ◽  
Author(s):  
Flavia Chiuppesi ◽  
Marcela d’Alincourt Salazar ◽  
Heidi Contreras ◽  
Vu H Nguyen ◽  
Joy Martinez ◽  
...  
Keyword(s):  
Immune Responses ◽  
Neutralizing Antibodies ◽  
Protective Immunity ◽  
Vaccine Candidate ◽  
Vaccine Platform ◽  
Synthetic Dna ◽  
Cellular Immune Responses ◽  
Global Pandemic ◽  
Immunodominant Antigens ◽  
Cellular Immune

AbstractModified Vaccinia Ankara (MVA) is a highly attenuated poxvirus vector that is widely used to develop vaccines for infectious diseases and cancer. We developed a novel vaccine platform based on a unique three-plasmid system to efficiently generate recombinant MVA vectors from chemically synthesized DNA. In response to the ongoing global pandemic caused by SARS coronavirus-2 (SARS-CoV-2), we used this novel vaccine platform to rapidly produce fully synthetic MVA (sMVA) vectors co-expressing SARS-CoV-2 spike and nucleocapsid antigens, two immunodominant antigens implicated in protective immunity. Mice immunized with these sMVA vectors developed robust SARS-CoV-2 antigen-specific humoral and cellular immune responses, including potent neutralizing antibodies. These results demonstrate the potential of a novel vaccine platform based on synthetic DNA to efficiently generate recombinant MVA vectors and to rapidly develop a multi-antigenic poxvirus-based SARS-CoV-2 vaccine candidate.

scholarly journals Cellular and humoral immunogenicity of a candidate DNA Vaccine Expressing SARS-CoV-2 Spike Subunit 1

2021 ◽  
Author(s):  
Khalid A. Alluhaybi ◽  
Rahaf H. Alharbi ◽  
Rowa Y. Alhabbab ◽  
Najwa D Aljehani ◽  
Sawsan S. Alamri ◽  
...  
Keyword(s):  
Immune Responses ◽  
Dna Vaccine ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Specific Igg ◽  
Cellular Immune ◽  
Different Doses

The urgent need for effective, safe and equitably accessible vaccines to tackle the ongoing spread of COVID-19 led researchers to generate vaccine candidates targeting varieties of immunogens of SARS-CoV-2. Because of its crucial role in mediating binding and entry to host cell and its proven safety profile, the subunit 1 (S1) of the spike protein represents an attractive immunogen for vaccine development. Here, we developed and assessed the immunogenicity of a DNA vaccine encoding the SARS-CoV-2 S1. Following in vitro confirmation and characterization, the humoral and cellular immune responses of our vaccine candidate (pVAX-S1) was evaluated in BALB/c mice using two different doses, 25 µg and 50 µg. Our data showed high levels of SARS-CoV-2 specific IgG and neutralizing antibodies in mice immunized with three doses of pVAX-S1. Analysis of the induced IgG subclasses showed a Th1-polarized immune response as demonstrated by the significant elevation of spike-specific IgG2a and IgG2b compared to IgG1. Furthermore, we found that immunization of mice with three doses of 50 µg of pVAX-S1 could elicit significant memory CD4+ and CD8+ T cell responses. Taken together, our data indicates that pVAX-S1 is immunogenic and safe in mice and is worthy of further preclinical and clinical evaluation.

scholarly journals An Exposed Domain in the Severe Acute Respiratory Syndrome Coronavirus Spike Protein Induces Neutralizing Antibodies

2004 ◽  
Vol 78 (13) ◽  
pp. 7217-7226 ◽  
Author(s):  
Tong Zhou ◽  
Hong Wang ◽  
Danlin Luo ◽  
Thomas Rowe ◽  
Zheng Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Severe Acute Respiratory Syndrome ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Vero Cells ◽  
Spike Protein ◽  
Protein Fragment

ABSTRACT Exposed epitopes of the spike protein may be recognized by neutralizing antibodies against severe acute respiratory syndrome (SARS) coronavirus (CoV). A protein fragment (S-II) containing predicted epitopes of the spike protein was expressed in Escherichia coli. The properly refolded protein fragment specifically bound to the surface of Vero cells. Monoclonal antibodies raised against this fragment recognized the native spike protein of SARS CoV in both monomeric and trimeric forms. These monoclonal antibodies were capable of blocking S-II attachment to Vero cells and exhibited in vitro antiviral activity. These neutralizing antibodies mapped to epitopes in two peptides, each comprising 20 amino acids. Thus, this region of the spike protein might be a target for generation of therapeutic neutralizing antibodies against SARS CoV and for vaccine development to elicit protective humoral immunity.

scholarly journals Effects of Size and Surface Properties of Nanodiamonds on the Immunogenicity of Plant-Based H5 Protein of A/H5N1 Virus in Mice

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1597
Author(s):  
Thuong Thi Ho ◽  
Van Thi Pham ◽  
Tra Thi Nguyen ◽  
Vy Thai Trinh ◽  
Tram Vi ◽  
...  
Keyword(s):  
High Pressure ◽  
Neutralizing Antibodies ◽  
H5n1 Virus ◽  
Vaccine Development ◽  
Particle Characterization ◽  
Innovative Strategy ◽  
Specific Igg ◽  
Positively Charged

Nanodiamond (ND) has recently emerged as a potential nanomaterial for nanovaccine development. Here, a plant-based haemagglutinin protein (H5.c2) of A/H5N1 virus was conjugated with detonation NDs (DND) of 3.7 nm in diameter (ND4), and high-pressure and high-temperature (HPHT) oxidative NDs of ~40–70 nm (ND40) and ~100–250 nm (ND100) in diameter. Our results revealed that the surface charge, but not the size of NDs, is crucial to the protein conjugation, as well as the in vitro and in vivo behaviors of H5.c2:ND conjugates. Positively charged ND4 does not effectively form stable conjugates with H5.c2, and has no impact on the immunogenicity of the protein both in vitro and in vivo. In contrast, the negatively oxidized NDs (ND40 and ND100) are excellent protein antigen carriers. When compared to free H5.c2, H5.c2:ND40, and H5.c2:ND100 conjugates are highly immunogenic with hemagglutination titers that are both 16 times higher than that of the free H5.c2 protein. Notably, H5.c2:ND40 and H5.c2:ND100 conjugates induce over 3-folds stronger production of both H5.c2-specific-IgG and neutralizing antibodies against A/H5N1 than free H5.c2 in mice. These findings support the innovative strategy of using negatively oxidized ND particles as novel antigen carriers for vaccine development, while also highlighting the importance of particle characterization before use.

scholarly journals A Combined Adjuvant TF–Al Consisting of TFPR1 and Aluminum Hydroxide Augments Strong Humoral and Cellular Immune Responses in Both C57BL/6 and BALB/c Mice

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1408
Author(s):  
Qiao Li ◽  
Zhihua Liu ◽  
Yi Liu ◽  
Chen Liang ◽  
Jiayi Shu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Vaccine Development ◽  
Inbred Mouse ◽  
Effective Vaccine ◽  
Mouse Strains ◽  
Cellular Immune Responses ◽  
Recombinant Hbsag ◽  
Cellular Immune

TFPR1 is a novel adjuvant for protein and peptide antigens, which has been demonstrated in BALB/c mice in our previous studies; however, its adjuvanticity in mice with different genetic backgrounds remains unknown, and its adjuvanticity needs to be improved to fit the requirements for various vaccines. In this study, we first compared the adjuvanticity of TFPR1 in two commonly used inbred mouse strains, BALB/c and C57BL/6 mice, in vitro and in vivo, and demonstrated that TFPR1 activated TLR2 to exert its immune activity in vivo. Next, to prove the feasibility of TFPR1 acting as a major component of combined adjuvants, we prepared a combined adjuvant, TF–Al, by formulating TFPR1 and alum at a certain ratio and compared its adjuvanticity with that of TFPR1 and alum alone using OVA and recombinant HBsAg as model antigens in both BALB/c and C57BL/6 mice. Results showed that TFPR1 acts as an effective vaccine adjuvant in both BALB/c mice and C57BL/6 mice, and further demonstrated the role of TLR2 in the adjuvanticity of TFPR1 in vivo. In addition, we obtained a novel combined adjuvant, TF–Al, based on TFPR1, which can augment antibody and cellular immune responses in mice with different genetic backgrounds, suggesting its promise for vaccine development in the future.

scholarly journals VLP-Based COVID-19 Vaccines: An Adaptable Technology against the Threat of New Variants

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1409
Author(s):  
Wasim A. Prates-Syed ◽  
Lorena C. S. Chaves ◽  
Karin P. Crema ◽  
Larissa Vuitika ◽  
Aline Lira ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Evasion ◽  
Convergent Evolution ◽  
Vaccine Development ◽  
Receptor Binding Domain ◽  
Vaccine Platform ◽  
Cellular Immune Responses ◽  
Alpha Beta ◽  
Cellular Immune ◽  
Financial Losses

Virus-like particles (VLPs) are a versatile, safe, and highly immunogenic vaccine platform. Recently, there are developmental vaccines targeting SARS-CoV-2, the causative agent of COVID-19. The COVID-19 pandemic affected humanity worldwide, bringing out incomputable human and financial losses. The race for better, more efficacious vaccines is happening almost simultaneously as the virus increasingly produces variants of concern (VOCs). The VOCs Alpha, Beta, Gamma, and Delta share common mutations mainly in the spike receptor-binding domain (RBD), demonstrating convergent evolution, associated with increased transmissibility and immune evasion. Thus, the identification and understanding of these mutations is crucial for the production of new, optimized vaccines. The use of a very flexible vaccine platform in COVID-19 vaccine development is an important feature that cannot be ignored. Incorporating the spike protein and its variations into VLP vaccines is a desirable strategy as the morphology and size of VLPs allows for better presentation of several different antigens. Furthermore, VLPs elicit robust humoral and cellular immune responses, which are safe, and have been studied not only against SARS-CoV-2 but against other coronaviruses as well. Here, we describe the recent advances and improvements in vaccine development using VLP technology.

Chimeric virus-like particles of universal antigen epitopes of coronavirus and phage Qβ coat protein trigger the production of neutralizing antibodies

2021 ◽  
Vol 21 ◽  
Author(s):  
Yukun Guo ◽  
Ruizhen Guo ◽  
Yingxian Ma ◽  
Wenru Chang ◽  
Shengli Ming ◽  
...  
Keyword(s):  
Coat Protein ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Genetic Recombination ◽  
Fluorescent Label ◽  
Salting Out ◽  
Virus Like Particles ◽  
Chimeric Vlps ◽  
Universal Epitope

Background: Virus-like particles (VLPs) are non-genetic multimeric nanoparticles synthesized through in vitro or in vivo self-assembly of one or more viral structural proteins. Immunogenicity and safety of VLPs make them ideal candidates for vaccine development and efficient nanocarriers for foreign antigens or adjuvants to activate the immune system. Aims: The present study aimed to design and synthesize a chimeric VLP vaccine of the phage Qbeta (Qβ) coat protein presenting the universal epitope of the coronavirus. Methods: The RNA phage Qβ coat protein was designed and synthesized, denoted as Qbeta. The CoV epitope, a universal epitope of coronavirus, was inserted into the C-terminal of Qbeta using genetic recombination, which was designated as Qbeta-CoV. The N-terminal of Qbeta-CoV was successively inserted into the TEV restriction site using mCherry red fluorescent label and modified affinity-purified histidine label 6xHE, which was denoted as HE-Qbeta-CoV. Isopropyl β-D-1-thiogalactopyranoside (IPTG) assessment revealed the expression of Qbeta, Qbeta-CoV, and HE-Qbeta-CoV in the BL21 (DE3) cells. The fusion protein was purified by salting out using ammonium sulfate and affinity chromatography. The morphology of particles was observed using electron microscopy. The female BALB/C mice were immunized intraperitoneally with the Qbeta-CoV and HE-Qbeta-CoV chimeric VLPs vaccines. Their sera were collected for the detection of antibody level and antibody titer using ELISA. The serum is used for the neutralization test of the three viruses of MHV, PEDV, and PDCoV. Results: The results revealed that the fusion proteins Qbeta, Qbeta-CoV, and HE-Qbeta-CoV could all obtain successful expression. Particles with high purity were obtained after purification; the chimeric particles of Qbeta-CoV and HE-Qbeta-CoV were found to be similar to Qbeta particles in morphology and formed chimeric VLPs. In addition, two chimeric VLP vaccines induced specific antibody responses in mice, and the antibodies showed certain neutralizing activity. Conclusion: The successful construction of the chimeric VLPs of the phage Qβ coat protein presenting the universal epitope of coronavirus provides a vaccine form with potential clinical applications for the treatment of coronavirus disease.

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