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1.
Cell Rep ; 38(3): 110256, 2022 01 18.
Article in English | MEDLINE | ID: covidwho-1588136

ABSTRACT

Inoculation against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is ongoing worldwide. However, the emergence of SARS-CoV-2 variants could cause immune evasion. We developed a bivalent nanoparticle vaccine that displays the receptor binding domains (RBDs) of the D614G and B.1.351 strains. With a prime-boost or a single-dose strategy, this vaccine elicits a robust neutralizing antibody and full protection against infection with the authentic D614G or B.1.351 strain in human angiotensin-converting enzyme 2 transgene mice. Interestingly, 8 months after inoculation with the D614G-specific vaccine, a new boost with this bivalent vaccine potently elicits cross-neutralizing antibodies for SARS-CoV-2 variants in rhesus macaques. We suggest that the D614G/B.1.351 bivalent vaccine could be used as an initial single dose or a sequential enforcement dose to prevent infection with SARS-CoV-2 and its variants.


Subject(s)
COVID-19/prevention & control , Cross Protection , SARS-CoV-2/immunology , Vaccines, Combined/therapeutic use , Animals , CHO Cells , COVID-19 Vaccines/chemical synthesis , COVID-19 Vaccines/immunology , COVID-19 Vaccines/therapeutic use , Chlorocebus aethiops , Cricetulus , Cross Protection/immunology , Female , HEK293 Cells , Humans , Macaca mulatta , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Transgenic , Nanoparticles , Vaccination/methods , Vaccines, Combined/chemical synthesis , Vaccines, Combined/immunology , Vero Cells
2.
Front Immunol ; 12: 692937, 2021.
Article in English | MEDLINE | ID: covidwho-1403473

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) kills thousands of people worldwide every day, thus necessitating rapid development of countermeasures. Immunoinformatics analyses carried out here in search of immunodominant regions in recently identified SARS-CoV-2 unannotated open reading frames (uORFs) have identified eight linear B-cell, one conformational B-cell, 10 CD4+ T-cell, and 12 CD8+ T-cell promising epitopes. Among them, ORF9b B-cell and T-cell epitopes are the most promising followed by M.ext and ORF3c epitopes. ORF9b40-48 (CD8+ T-cell epitope) is found to be highly immunogenic and antigenic with the highest allele coverage. Furthermore, it has overlap with four potent CD4+ T-cell epitopes. Structure-based B-cell epitope prediction has identified ORF9b61-68 to be immunodominant, which partially overlaps with one of the linear B-cell epitopes (ORF9b65-69). ORF3c CD4+ T-cell epitopes (ORF3c2-16, ORF3c3-17, and ORF3c4-18) and linear B-cell epitope (ORF3c14-22) have also been identified as the candidate epitopes. Similarly, M.ext and 7a.iORF1 (overlap with M and ORF7a) proteins have promising immunogenic regions. By considering the level of antigen expression, four ORF9b and five M.ext epitopes are finally shortlisted as potent epitopes. Mutation analysis has further revealed that the shortlisted potent uORF epitopes are resistant to recurrent mutations. Additionally, four N-protein (expressed by canonical ORF) epitopes are found to be potent. Thus, SARS-CoV-2 uORF B-cell and T-cell epitopes identified here along with canonical ORF epitopes may aid in the design of a promising epitope-based polyvalent vaccine (when connected through appropriate linkers) against SARS-CoV-2. Such a vaccine can act as a bulwark against SARS-CoV-2, especially in the scenario of emergence of variants with recurring mutations in the spike protein.


Subject(s)
Antigens, Viral/immunology , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Amino Acid Sequence/genetics , Antigens, Viral/genetics , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/therapeutic use , Computational Biology , Coronavirus Nucleocapsid Proteins/genetics , Drug Design , Epitope Mapping , Epitopes, B-Lymphocyte/genetics , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/genetics , Epitopes, T-Lymphocyte/immunology , Humans , Open Reading Frames/genetics , Open Reading Frames/immunology , SARS-CoV-2/genetics , Sequence Analysis, Protein , Vaccines, Combined/genetics , Vaccines, Combined/immunology
3.
Commun Biol ; 4(1): 597, 2021 05 19.
Article in English | MEDLINE | ID: covidwho-1236095

ABSTRACT

The COVID-19 pandemic continues to wreak havoc as worldwide SARS-CoV-2 infection, hospitalization, and death rates climb unabated. Effective vaccines remain the most promising approach to counter SARS-CoV-2. Yet, while promising results are emerging from COVID-19 vaccine trials, the need for multiple doses and the challenges associated with the widespread distribution and administration of vaccines remain concerns. Here, we engineered the coat protein of the MS2 bacteriophage and generated nanoparticles displaying multiple copies of the SARS-CoV-2 spike (S) protein. The use of these nanoparticles as vaccines generated high neutralizing antibody titers and protected Syrian hamsters from a challenge with SARS-CoV-2 after a single immunization with no infectious virus detected in the lungs. This nanoparticle-based vaccine platform thus provides protection after a single immunization and may be broadly applicable for protecting against SARS-CoV-2 and future pathogens with pandemic potential.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/immunology , COVID-19/prevention & control , Pandemics , SARS-CoV-2 , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Drug Delivery Systems , Female , Humans , Immunization/methods , Levivirus/genetics , Levivirus/immunology , Mesocricetus , Microscopy, Electron, Transmission , Models, Animal , Nanoparticles/administration & dosage , Nanoparticles/ultrastructure , Nanotechnology , Pandemics/prevention & control , Protein Engineering , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/administration & dosage , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Combined/administration & dosage , Vaccines, Combined/genetics , Vaccines, Combined/immunology , Vaccines, Virus-Like Particle/administration & dosage , Vaccines, Virus-Like Particle/genetics , Vaccines, Virus-Like Particle/immunology
4.
Infect Genet Evol ; 89: 104712, 2021 04.
Article in English | MEDLINE | ID: covidwho-1196742

ABSTRACT

An immunoinformatics-based approach was used to identify potential multivalent subunit CTL vaccine candidates for SARS-CoV-2. Criteria for computational screening included antigen processing, antigenicity, allergenicity, and toxicity. A total of 2604 epitopes were found to be strong binders to MHC class I molecules when analyzed using IEDB tools. Further testing for antigen processing yielded 826 peptides of which 451 were 9-mers that were analyzed for potential antigenicity. Antigenic properties were predicted for 102 of the 451 peptides. Further assessment for potential allergenicity and toxicity narrowed the number of candidate CTL epitopes to 50 peptide sequences, 45 of which were present in all strains of SARS-CoV-2 that were tested. The predicted CTL epitopes were then tested to eliminate those with MHC class II binding potential, a property that could induce hyperinflammatory responses mediated by TH2 cells in immunized hosts. Eighteen of the 50 epitopes did not show class II binding potential. To our knowledge this is the first comprehensive analysis on the proteome of SARS-CoV-2 for prediction of CTL epitopes lacking binding properties that could stimulate unwanted TH2 responses. Future studies will be needed to assess these epitopes as multivalent subunit vaccine candidates which stimulate protective CTL responses against SARS-COV-2.


Subject(s)
COVID-19 Vaccines/immunology , Epitopes, T-Lymphocyte/immunology , Vaccines, Combined/immunology , Vaccines, Subunit/immunology , Amino Acid Sequence , COVID-19/prevention & control , Epitopes, T-Lymphocyte/chemistry , Histocompatibility Antigens Class I/immunology , Histocompatibility Antigens Class II/immunology , Humans , Immunogenicity, Vaccine/immunology , Molecular Docking Simulation , Proteomics/methods , T-Lymphocytes, Cytotoxic/immunology
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