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1.
Front Immunol ; 12: 732298, 2021.
Article in English | MEDLINE | ID: covidwho-1506693

ABSTRACT

Immune modulating therapies and vaccines are in high demand, not least to the recent global spread of SARS-CoV2. To achieve efficient activation of the immune system, professional antigen presenting cells have proven to be key coordinators of such responses. Especially targeted approaches, actively directing antigens to specialized dendritic cells, promise to be more effective and accompanied by reduced payload due to less off-target effects. Although antibody and glycan-based targeting of receptors on dendritic cells have been employed, these are often expensive and time-consuming to manufacture or lack sufficient specificity. Thus, we applied a small-molecule ligand that specifically binds Langerin, a hallmark receptor on Langerhans cells, conjugated to a model protein antigen. Via microneedle injection, this construct was intradermally administered into intact human skin explants, selectively loading Langerhans cells in the epidermis. The ligand-mediated cellular uptake outpaces protein degradation resulting in intact antigen delivery. Due to the pivotal role of Langerhans cells in induction of immune responses, this approach of antigen-targeting of tissue-resident immune cells offers a novel way to deliver highly effective vaccines with minimally invasive administration.


Subject(s)
Antigens, CD/metabolism , Antigens/administration & dosage , Green Fluorescent Proteins/administration & dosage , Langerhans Cells/metabolism , Lectins, C-Type/metabolism , Mannose-Binding Lectins/metabolism , Animals , Antigens/immunology , Antigens/metabolism , COS Cells , Chlorocebus aethiops , Green Fluorescent Proteins/metabolism , HEK293 Cells , Humans , Injections, Intradermal , Langerhans Cells/immunology , Ligands , Miniaturization , Nanomedicine , Needles , Protein Binding , Protein Transport , Proteolysis , THP-1 Cells , Vaccines, Subunit/administration & dosage , Vaccines, Subunit/immunology , Vaccines, Subunit/metabolism
2.
Adv Mater ; 33(51): e2104362, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1469404

ABSTRACT

The development of effective vaccines that can be rapidly manufactured and distributed worldwide is necessary to mitigate the devastating health and economic impacts of pandemics like COVID-19. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein, which mediates host cell entry of the virus, is an appealing antigen for subunit vaccines because it is efficient to manufacture, highly stable, and a target for neutralizing antibodies. Unfortunately, RBD is poorly immunogenic. While most subunit vaccines are commonly formulated with adjuvants to enhance their immunogenicity, clinically-relevant adjuvants Alum, AddaVax, and CpG/Alum are found unable to elicit neutralizing responses following a prime-boost immunization. Here, it has been shown that sustained delivery of an RBD subunit vaccine comprising CpG/Alum adjuvant in an injectable polymer-nanoparticle (PNP) hydrogel elicited potent anti-RBD and anti-spike antibody titers, providing broader protection against SARS-CoV-2 variants of concern compared to bolus administration of the same vaccine and vaccines comprising other clinically-relevant adjuvant systems. Notably, a SARS-CoV-2 spike-pseudotyped lentivirus neutralization assay revealed that hydrogel-based vaccines elicited potent neutralizing responses when bolus vaccines did not. Together, these results suggest that slow delivery of RBD subunit vaccines with PNP hydrogels can significantly enhance the immunogenicity of RBD and induce neutralizing humoral immunity.


Subject(s)
Antibodies, Neutralizing/immunology , Hydrogels/chemistry , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Subunit/immunology , Adjuvants, Immunologic/chemistry , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/prevention & control , COVID-19/virology , CpG Islands/genetics , Female , Humans , Immunity, Humoral , Mice , Mice, Inbred C57BL , Nanoparticles/chemistry , Polymers/chemistry , Protein Domains/immunology , SARS-CoV-2/chemistry , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/isolation & purification , Vaccines, Subunit/chemistry , Vaccines, Subunit/metabolism
3.
Immunogenetics ; 73(6): 459-477, 2021 12.
Article in English | MEDLINE | ID: covidwho-1427234

ABSTRACT

Since 2019, the world was involved with SARS-CoV-2 and consequently, with the announcement by the World Health Organization that COVID-19 was a pandemic, scientific were an effort to obtain the best approach to combat this global dilemma. The best way to prevent the pandemic from spreading further is to use a vaccine against COVID-19. Here, we report the design of a recombinant multi-epitope vaccine against the four proteins spike or crown (S), membrane (M), nucleocapsid (N), and envelope (E) of SARS-CoV-2 using immunoinformatics tools. We evaluated the most antigenic epitopes that bind to HLA class 1 subtypes, along with HLA class 2, as well as B cell epitopes. Beta-defensin 3 and PADRE sequence were used as adjuvants in the structure of the vaccine. KK, GPGPG, and AAY linkers were used to fuse the selected epitopes. The nucleotide sequence was cloned into pET26b(+) vector using restriction enzymes XhoI and NdeI, and HisTag sequence was considered in the C-terminal of the construct. The results showed that the proposed candidate vaccine is a 70.87 kDa protein with high antigenicity and immunogenicity as well as non-allergenic and non-toxic. A total of 95% of the selected epitopes have conservancy with similar sequences. Molecular docking showed a strong binding between the vaccine structure and tool-like receptor (TLR) 7/8. The docking, molecular dynamics, and MM/PBSA analysis showed that the vaccine established a stable interaction with both structures of TLR7 and TLR8. Simulation of immune stimulation by this vaccine showed that it evokes immune responses related to humoral and cellular immunity.


Subject(s)
COVID-19 Vaccines/immunology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , SARS-CoV-2/immunology , Amino Acid Sequence , Base Sequence , COVID-19/prevention & control , COVID-19 Vaccines/genetics , COVID-19 Vaccines/metabolism , Computational Biology , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/genetics , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/genetics , HLA Antigens/immunology , Humans , Immunogenicity, Vaccine , Molecular Docking Simulation , Molecular Dynamics Simulation , Molecular Weight , Recombinant Fusion Proteins/chemistry , Recombinant Fusion Proteins/genetics , Recombinant Fusion Proteins/immunology , Toll-Like Receptor 7/chemistry , Toll-Like Receptor 8/chemistry , Vaccines, Subunit/genetics , Vaccines, Subunit/immunology , Vaccines, Subunit/metabolism , Vaccinology , Viral Proteins/chemistry , Viral Proteins/genetics , Viral Proteins/immunology
4.
J Am Chem Soc ; 143(36): 14748-14765, 2021 09 15.
Article in English | MEDLINE | ID: covidwho-1397838

ABSTRACT

The COVID-19 pandemic highlights the need for platform technologies enabling rapid development of vaccines for emerging viral diseases. The current vaccines target the SARS-CoV-2 spike (S) protein and thus far have shown tremendous efficacy. However, the need for cold-chain distribution, a prime-boost administration schedule, and the emergence of variants of concern (VOCs) call for diligence in novel SARS-CoV-2 vaccine approaches. We studied 13 peptide epitopes from SARS-CoV-2 and identified three neutralizing epitopes that are highly conserved among the VOCs. Monovalent and trivalent COVID-19 vaccine candidates were formulated by chemical conjugation of the peptide epitopes to cowpea mosaic virus (CPMV) nanoparticles and virus-like particles (VLPs) derived from bacteriophage Qß. Efficacy of this approach was validated first using soluble vaccine candidates as solo or trivalent mixtures and subcutaneous prime-boost injection. The high thermal stability of our vaccine candidates allowed for formulation into single-dose injectable slow-release polymer implants, manufactured by melt extrusion, as well as microneedle (MN) patches, obtained through casting into micromolds, for prime-boost self-administration. Immunization of mice yielded high titers of antibodies against the target epitope and S protein, and data confirms that antibodies block receptor binding and neutralize SARS-CoV and SARS-CoV-2 against infection of human cells. We present a nanotechnology vaccine platform that is stable outside the cold-chain and can be formulated into delivery devices enabling single administration or self-administration. CPMV or Qß VLPs could be stockpiled, and epitopes exchanged to target new mutants or emergent diseases as the need arises.


Subject(s)
COVID-19 Vaccines/metabolism , COVID-19/epidemiology , COVID-19/prevention & control , Delayed-Action Preparations/chemistry , SARS-CoV-2/metabolism , Vaccines, Subunit/metabolism , Animals , Comovirus , Computer Simulation , Drug Compounding , Epitopes/chemistry , Hot Temperature , Humans , Male , Mice, Inbred BALB C , Nanoparticles/chemistry , Peptides/chemistry , Vaccination , Vaccines, Virus-Like Particle/chemistry
5.
J Phys Chem Lett ; 11(22): 9920-9930, 2020 Nov 19.
Article in English | MEDLINE | ID: covidwho-919398

ABSTRACT

The emergence of severe acute respiratory syndrome from novel Coronavirus (SARS-CoV-2) has put an immense pressure worldwide where vaccination is believed to be an efficient way for developing hard immunity. Herein, we employ immunoinformatic tools to identify B-cell, T-cell epitopes associated with the spike protein of SARS-CoV-2, which is important for genome release. The results showed that the highly immunogenic epitopes located at the stalk part are mostly conserved compared to the receptor binding domain (RDB). Further, two vaccine candidates were computationally modeled from the linear B-cell, T-cell epitopes. Molecular docking reveals the crucial interactions of the vaccines with immune-receptors, and their stability is assessed by MD simulation studies. The chimeric vaccines showed remarkable binding affinity toward the immune cell receptors computed by the MM/PBSA method. van der Waals and electrostatic interactions are found to be the dominant factors for the stability of the complexes. The molecular-level interaction obtained from this study may provide deeper insight into the process of vaccine development against the pandemic of COVID-19.


Subject(s)
COVID-19 Vaccines/immunology , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Subunit/immunology , Amino Acid Sequence , COVID-19/prevention & control , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/metabolism , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/metabolism , Epitopes, T-Lymphocyte/chemistry , Epitopes, T-Lymphocyte/metabolism , Molecular Docking Simulation , Molecular Dynamics Simulation , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Vaccines, Subunit/chemistry , Vaccines, Subunit/metabolism
6.
Infect Genet Evol ; 85: 104517, 2020 11.
Article in English | MEDLINE | ID: covidwho-737519

ABSTRACT

The present study aimed to predict a novel chimeric vaccine by simultaneously targeting four major structural proteins via the establishment of ancestral relationship among different strains of coronaviruses. Conserved regions from the homologous protein sets of spike glycoprotein, membrane protein, envelope protein and nucleocapsid protein were identified through multiple sequence alignment. The phylogeny analyses of whole genome stated that four proteins reflected the close ancestral relation of SARS-CoV-2 to SARS-COV-1 and bat coronavirus. Numerous immunogenic epitopes (both T cell and B cell) were generated from the common fragments which were further ranked on the basis of antigenicity, transmembrane topology, conservancy level, toxicity and allergenicity pattern and population coverage analysis. Top putative epitopes were combined with appropriate adjuvants and linkers to construct a novel multiepitope subunit vaccine against COVID-19. The designed constructs were characterized based on physicochemical properties, allergenicity, antigenicity and solubility which revealed the superiority of construct V3 in terms safety and efficacy. Essential molecular dynamics and normal mode analysis confirmed minimal deformability of the refined model at molecular level. In addition, disulfide engineering was investigated to accelerate the stability of the protein. Molecular docking study ensured high binding affinity between construct V3 and HLA cells, as well as with different host receptors. Microbial expression and translational efficacy of the constructs were checked using pET28a(+) vector of E. coli strain K12. However, the in vivo and in vitro validation of suggested vaccine molecule might be ensured with wet lab trials using model animals for the implementation of the presented data.


Subject(s)
Epitopes, B-Lymphocyte/genetics , Epitopes, T-Lymphocyte/genetics , SARS-CoV-2/classification , Vaccines, Subunit/genetics , Viral Structural Proteins/genetics , Epitopes, B-Lymphocyte/immunology , Epitopes, T-Lymphocyte/immunology , Escherichia coli/genetics , Escherichia coli/growth & development , Evolution, Molecular , Genome, Viral , Humans , Models, Molecular , Molecular Docking Simulation , Molecular Dynamics Simulation , Phylogeny , Protein Conformation , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Vaccines, Subunit/chemistry , Vaccines, Subunit/metabolism , Viral Structural Proteins/chemistry , Viral Structural Proteins/immunology , Viral Vaccines/chemistry , Viral Vaccines/genetics , Viral Vaccines/metabolism
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