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1.
Lancet ; 399(10332): 1281-1282, 2022 Apr 02.
Article in English | MEDLINE | ID: covidwho-1768610
2.
Proc Natl Acad Sci U S A ; 119(14): e2119093119, 2022 04 05.
Article in English | MEDLINE | ID: covidwho-1751830

ABSTRACT

SignificanceUsing SARS-CoV-2 as a relevant case study for infectious disease, we investigate the structure-function relationships that dictate antiviral spherical nucleic acid (SNA) vaccine efficacy. We show that the SNA architecture can be rapidly employed to target COVID-19 through incorporation of the receptor-binding domain, and that the resulting vaccine potently activates human cells in vitro and mice in vivo. Furthermore, when challenged with a lethal viral infection, only mice treated with the SNA vaccine survived. Taken together, this work underscores the importance of rational vaccine design for infectious disease to yield vaccines that elicit more potent immune responses to effectively fight disease.


Subject(s)
Communicable Disease Control , Nucleic Acids/immunology , Vaccines, DNA/immunology , Animals , Biotechnology , COVID-19/prevention & control , Communicable Disease Control/methods , Communicable Diseases/etiology , Communicable Diseases/immunology , Humans , Nucleic Acids/chemistry , SARS-CoV-2/immunology , Vaccines, DNA/genetics , Viral Vaccines/genetics , Viral Vaccines/immunology
3.
Front Immunol ; 13: 827605, 2022.
Article in English | MEDLINE | ID: covidwho-1742217

ABSTRACT

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a public health emergency of international concern, and an effective vaccine is urgently needed to control the pandemic. Envelope (E) and membrane (M) proteins are highly conserved structural proteins among SARS-CoV-2 and SARS-CoV and have been proposed as potential targets for the development of cross-protective vaccines. Here, synthetic DNA vaccines encoding SARS-CoV-2 E/M proteins (called p-SARS-CoV-2-E/M) were developed, and mice were immunised with three doses via intramuscular injection and electroporation. Significant cellular immune responses were elicited, whereas no robust humoral immunity was detected. In addition, novel H-2d-restricted T-cell epitopes were identified. Notably, although no drop in lung tissue virus titre was detected in DNA-vaccinated mice post-challenge with SARS-CoV-2, immunisation with either p-SARS-CoV-2-E or p-SARS-CoV-2-M provided minor protection and co-immunisation with p-SARS-CoV-2-E+M increased protection. Therefore, E/M proteins should be considered as vaccine candidates as they may be valuable in the optimisation of vaccination strategies against COVID-19.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , Coronavirus Envelope Proteins/genetics , Coronavirus M Proteins/genetics , SARS-CoV-2/physiology , T-Lymphocytes/immunology , Animals , Antibodies, Viral/blood , COVID-19 Vaccines/genetics , Female , Humans , Immunization , Mice , Mice, Inbred BALB C , Vaccines, DNA
4.
Int J Mol Sci ; 23(4)2022 Feb 16.
Article in English | MEDLINE | ID: covidwho-1708485

ABSTRACT

Despite the fact that a range of vaccines against COVID-19 have already been created and are used for mass vaccination, the development of effective, safe, technological, and affordable vaccines continues. We have designed a vaccine that combines the recombinant protein and DNA vaccine approaches in a self-assembled particle. The receptor-binding domain (RBD) of the spike protein of SARS-CoV-2 was conjugated to polyglucin:spermidine and mixed with DNA vaccine (pVAXrbd), which led to the formation of particles of combined coronavirus vaccine (CCV-RBD) that contain the DNA vaccine inside and RBD protein on the surface. CCV-RBD particles were characterized with gel filtration, electron microscopy, and biolayer interferometry. To investigate the immunogenicity of the combined vaccine and its components, mice were immunized with the DNA vaccine pVAXrbd or RBD protein as well as CCV-RBD particles. The highest antigen-specific IgG and neutralizing activity were induced by CCV-RBD, and the level of antibodies induced by DNA or RBD alone was significantly lower. The cellular immune response was detected only in the case of DNA or CCV-RBD vaccination. These results demonstrate that a combination of DNA vaccine and RBD protein in one construct synergistically increases the humoral response to RBD protein in mice.


Subject(s)
COVID-19 Vaccines/chemistry , COVID-19 Vaccines/pharmacology , Immunity, Humoral/drug effects , Spike Glycoprotein, Coronavirus/chemistry , Animals , Binding Sites , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Dextrans/chemistry , Female , HEK293 Cells , Humans , Mice, Inbred BALB C , Protein Domains , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Spermidine/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccines, DNA/genetics , Vaccines, DNA/immunology , Vaccines, DNA/pharmacology , Vero Cells
5.
PLoS Pathog ; 17(9): e1009701, 2021 09.
Article in English | MEDLINE | ID: covidwho-1701737

ABSTRACT

The speed of development, versatility and efficacy of mRNA-based vaccines have been amply demonstrated in the case of SARS-CoV-2. DNA vaccines represent an important alternative since they induce both humoral and cellular immune responses in animal models and in human trials. We tested the immunogenicity and protective efficacy of DNA-based vaccine regimens expressing different prefusion-stabilized Wuhan-Hu-1 SARS-CoV-2 Spike antigens upon intramuscular injection followed by electroporation in rhesus macaques. Different Spike DNA vaccine regimens induced antibodies that potently neutralized SARS-CoV-2 in vitro and elicited robust T cell responses. The antibodies recognized and potently neutralized a panel of different Spike variants including Alpha, Delta, Epsilon, Eta and A.23.1, but to a lesser extent Beta and Gamma. The DNA-only vaccine regimens were compared to a regimen that included co-immunization of Spike DNA and protein in the same anatomical site, the latter of which showed significant higher antibody responses. All vaccine regimens led to control of SARS-CoV-2 intranasal/intratracheal challenge and absence of virus dissemination to the lower respiratory tract. Vaccine-induced binding and neutralizing antibody titers and antibody-dependent cellular phagocytosis inversely correlated with transient virus levels in the nasal mucosa. Importantly, the Spike DNA+Protein co-immunization regimen induced the highest binding and neutralizing antibodies and showed the strongest control against SARS-CoV-2 challenge in rhesus macaques.


Subject(s)
Macaca mulatta , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccines, DNA , Animals , COVID-19/immunology , COVID-19/therapy , Cohort Studies , DNA, Viral/immunology , Disease Models, Animal , Female , Immunization, Passive , Leukocytes, Mononuclear/immunology , Mice , RNA, Messenger/analysis , SARS-CoV-2/genetics , T-Lymphocytes/immunology , Vaccines, DNA/administration & dosage , Vaccines, DNA/immunology
6.
Front Immunol ; 12: 824728, 2021.
Article in English | MEDLINE | ID: covidwho-1686477

ABSTRACT

We generated an optimized COVID-19 vaccine candidate based on the modified vaccinia virus Ankara (MVA) vector expressing a full-length prefusion-stabilized SARS-CoV-2 spike (S) protein, termed MVA-CoV2-S(3P). The S(3P) protein was expressed at higher levels (2-fold) than the non-stabilized S in cells infected with the corresponding recombinant MVA viruses. One single dose of MVA-CoV2-S(3P) induced higher IgG and neutralizing antibody titers against parental SARS-CoV-2 and variants of concern than MVA-CoV2-S in wild-type C57BL/6 and in transgenic K18-hACE2 mice. In immunized C57BL/6 mice, two doses of MVA-CoV2-S or MVA-CoV2-S(3P) induced similar levels of SARS-CoV-2-specific B- and T-cell immune responses. Remarkably, a single administration of MVA-CoV2-S(3P) protected all K18-hACE2 mice from morbidity and mortality caused by SARS-CoV-2 infection, reducing SARS-CoV-2 viral loads, histopathological lesions, and levels of pro-inflammatory cytokines in the lungs. These results demonstrated that expression of a novel full-length prefusion-stabilized SARS-CoV-2 S protein by the MVA poxvirus vector enhanced immunogenicity and efficacy against SARS-CoV-2 in animal models, further supporting MVA-CoV2-S(3P) as an optimized vaccine candidate for clinical trials.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccines, DNA/immunology , Viral Vaccines/immunology , Aged , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19/mortality , COVID-19 Vaccines/genetics , Cell Line, Tumor , Chick Embryo , Chlorocebus aethiops , Cytokines/analysis , Female , HeLa Cells , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Plasmids/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccines, DNA/genetics , Vaccinia virus/immunology , Vero Cells , Viral Vaccines/genetics
7.
Viruses ; 14(2)2022 01 25.
Article in English | MEDLINE | ID: covidwho-1667339

ABSTRACT

In 2014 and 2021, two nucleic-acid vaccine candidates named MAV E2 and VGX-3100 completed phase III clinical trials in Mexico and U.S., respectively, for patients with human papillomavirus (HPV)-related, high-grade squamous intraepithelial lesions (HSIL). These well-tolerated but still unlicensed vaccines encode distinct HPV antigens (E2 versus E6+E7) to elicit cell-mediated immune responses; their clinical efficacy, as measured by HSIL regression or cure, was modest when compared with placebo or surgery (conization), but both proved highly effective in clearing HPV infection, which should help further optimize strategies for enhancing vaccine immunogenicity, toward an ultimate goal of preventing malignancies in millions of patients who are living with persistent, oncogenic HPV infection but are not expected to benefit from current, prophylactic vaccines. The major roadblocks to a highly efficacious and practical product remain challenging and can be classified into five categories: (i) getting the vaccines into the right cells for efficient expression and presentation of HPV antigens (fusion proteins or epitopes); (ii) having adequate coverage of oncogenic HPV types, beyond the current focus on HPV-16 and -18; (iii) directing immune protection to various epithelial niches, especially anogenital mucosa and upper aerodigestive tract where HPV-transformed cells wreak havoc; (iv) establishing the time window and vaccination regimen, including dosage, interval and even combination therapy, for achieving maximum efficacy; and (v) validating therapeutic efficacy in patients with poor prognosis because of advanced, recurrent or non-resectable malignancies. Overall, the room for improvements is still large enough that continuing efforts for research and development will very likely extend into the next decade.


Subject(s)
Cancer Vaccines/therapeutic use , Cervical Intraepithelial Neoplasia/therapy , Neoplasms/therapy , Papillomavirus Infections/therapy , Papillomavirus Vaccines/therapeutic use , Uterine Cervical Neoplasms/therapy , Vaccines, DNA/therapeutic use , Animals , Cervical Intraepithelial Neoplasia/immunology , Clinical Trials as Topic , Female , Humans , Immunogenicity, Vaccine , Neoplasms/immunology , Neoplasms/virology , Papillomavirus Infections/immunology , Papillomavirus Vaccines/immunology , Squamous Intraepithelial Lesions of the Cervix/therapy , Uterine Cervical Neoplasms/virology , Vaccines, DNA/immunology , /therapeutic use
8.
Exp Biol Med (Maywood) ; 247(4): 338-344, 2022 02.
Article in English | MEDLINE | ID: covidwho-1649460

ABSTRACT

The current SARS-CoV-2 pandemic diffused worldwide has encouraged the rapid development of vaccines to counter the spread of the virus. At present in Italy, 75.01% of the population completed the vaccination course (AIFA.gov.it) and very few adverse events have been recorded by now. Side-effects related to a theoretical over-reaction of the immune system in response to vaccines administration have been described, and the possibility that an autoimmune or a hyperinflammatory condition may occur was recently observed. Herein, we report four cases of hyperinflammatory syndrome with features indicative of Adult-onset Still's disease (AOSD) and macrophage activation syndrome (MAS), occurred after anti-SARS-CoV-2 vaccine injection and seen at our Unit between March and May 2021. Since interleukin (IL)-1 is one of the pivotal cytokines involved in AOSD pathogenesis, the inhibition of IL-1 is crucial in ameliorating the clinical symptoms of those patients. Moreover, it has been highlighted the central role of IL-1 as a hallmark of the hyperinflammatory status elicited by SARS-CoV-2 infection. In this case series, we successfully employed the IL-1 receptor antagonist anakinra to curb the cytokine release likely unleashed by the vaccine stimulation in potentially predisposed subjects. We also made a literature search to detect other patients with hyperinflammation temporally related to vaccines injection who benefited from IL-1 inhibition, while other AOSD/MAS-like described syndromes improved with other immunomodulatory strategies.


Subject(s)
COVID-19 Vaccines/adverse effects , Inflammation/chemically induced , Inflammation/drug therapy , Interleukin 1 Receptor Antagonist Protein/therapeutic use , /adverse effects , /adverse effects , Female , Humans , Interleukin-1/immunology , Interleukin-1/metabolism , Male , Middle Aged , Still's Disease, Adult-Onset/chemically induced , Still's Disease, Adult-Onset/etiology , Vaccines, DNA/adverse effects
9.
Biologicals ; 75: 12-15, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1616379

ABSTRACT

BACKGROUND: The successful development of messenger RNA vaccines for SARS-CoV-2 opened up venues for clinical nucleotide-based vaccinations. For development of DNA vaccines, we tested whether the EGF domain peptide of Developmentally regulated endothelial locus1 (E3 peptide) enhances uptake of extracellularly applied plasmid DNA. METHODS: DNA plasmid encoding lacZ or GFP was applied with a conditioned culture medium containing E3 peptide to cell lines in vitro or mouse soleus muscles in vivo, respectively. After 48 h incubation, gene expression was examined by ß-galactosidase (ß-gal) assay and fluorescent microscope, respectively. RESULTS: Application of E3 peptide-containing medium to cultured cell lines induced intense ß-gal activity in a dose-dependent manner. Intra-gastrocnemius injection of E3 peptide-containing medium to mouse soleus muscle succeeded in the induction of GFP fluorescence in many cells around the injection site. CONCLUSIONS: The administration of E3 peptide facilitates transmembrane uptake of extracellular DNA plasmid which induces sufficient extrinsic gene expression.


Subject(s)
DNA/genetics , Epidermal Growth Factor/chemistry , Gene Expression , Peptides , Plasmids/genetics , Plasmids/metabolism , Protein Domains , Animals , COVID-19 Vaccines , Cell Membrane/metabolism , DNA/metabolism , Genes, Reporter , Green Fluorescent Proteins/genetics , Mice , Muscle, Skeletal , Vaccines, DNA/genetics , Vaccines, DNA/metabolism
10.
EBioMedicine ; 75: 103762, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1587929

ABSTRACT

BACKGROUND: Vaccines in emergency use are efficacious against COVID-19, yet vaccine-induced prevention against nasal SARS-CoV-2 infection remains suboptimal. METHODS: Since mucosal immunity is critical for nasal prevention, we investigated the efficacy of an intramuscular PD1-based receptor-binding domain (RBD) DNA vaccine (PD1-RBD-DNA) and intranasal live attenuated influenza-based vaccines (LAIV-CA4-RBD and LAIV-HK68-RBD) against SARS-CoV-2. FINDINGS: Substantially higher systemic and mucosal immune responses, including bronchoalveolar lavage IgA/IgG and lung polyfunctional memory CD8 T cells, were induced by the heterologous PD1-RBD-DNA/LAIV-HK68-RBD as compared with other regimens. When vaccinated animals were challenged at the memory phase, prevention of robust SARS-CoV-2 infection in nasal turbinate was achieved primarily by the heterologous regimen besides consistent protection in lungs. The regimen-induced antibodies cross-neutralized variants of concerns. Furthermore, LAIV-CA4-RBD could boost the BioNTech vaccine for improved mucosal immunity. INTERPRETATION: Our results demonstrated that intranasal influenza-based boost vaccination induces mucosal and systemic immunity for effective SARS-CoV-2 prevention in both upper and lower respiratory systems. FUNDING: This study was supported by the Research Grants Council Collaborative Research Fund, General Research Fund and Health and Medical Research Fund in Hong Kong; Outbreak Response to Novel Coronavirus (COVID-19) by the Coalition for Epidemic Preparedness Innovations; Shenzhen Science and Technology Program and matching fund from Shenzhen Immuno Cure BioTech Limited; the Health@InnoHK, Innovation and Technology Commission of Hong Kong; National Program on Key Research Project of China; donations from the Friends of Hope Education Fund; the Theme-Based Research Scheme.


Subject(s)
COVID-19 Vaccines , COVID-19/prevention & control , Immunization, Secondary , Influenza Vaccines , SARS-CoV-2 , Vaccines, DNA , Administration, Intranasal , Animals , COVID-19/genetics , COVID-19/immunology , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Disease Models, Animal , Dogs , Female , HEK293 Cells , Humans , Immunity, Mucosal , Influenza Vaccines/genetics , Influenza Vaccines/immunology , Madin Darby Canine Kidney Cells , Male , Mice , Mice, Inbred BALB C , Mice, Transgenic , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Vaccines, DNA/genetics , Vaccines, DNA/immunology , Vero Cells
11.
Methods Mol Biol ; 2410: 229-263, 2022.
Article in English | MEDLINE | ID: covidwho-1575944

ABSTRACT

Vaccines are one of mankind's greatest medical advances, and their use has drastically reduced and in some cases eliminated (e.g., smallpox) disease and death caused by infectious agents. Traditional vaccine modalities including live-attenuated pathogen vaccines, wholly inactivated pathogen vaccines, and protein-based pathogen subunit vaccines have successfully been used to create efficacious vaccines against measles, mumps, rubella, polio, and yellow fever. These traditional vaccine modalities, however, take many months to years to develop and have thus proven less effective for use in creating vaccines to emerging or reemerging infectious diseases (EIDs) including influenza, Human immunodeficiency virus (HIV), dengue virus (DENV), chikungunya virus (CHIKV), West Nile virus (WNV), Middle East respiratory syndrome (MERS), and the severe acute respiratory syndrome coronaviruses 1 and 2 (SARS-CoV and SARS-CoV-2). As factors such as climate change and increased globalization continue to increase the pace of EID development, newer vaccine modalities are required to develop vaccines that can prevent or attenuate EID outbreaks throughout the world. One such modality, DNA vaccines, has been studied for over 30 years and has numerous qualities that make them ideal for meeting the challenge of EIDs including; (1) DNA vaccine candidates can be designed within hours of publishing of a pathogens genetic sequence; (2) they can be manufactured cheaply and rapidly in large quantities; (3) they are thermostable and have reduced requirement for a cold-chain during distribution, and (4) they have a remarkable safety record in the clinic. Optimizations made in plasmid design as well as in DNA vaccine delivery have greatly improved the immunogenicity of these vaccines. Here we describe the process of making a DNA vaccine to an EID pathogen and describe methods used for assessing the immunogenicity and protective efficacy of DNA vaccines in small animal models.


Subject(s)
Communicable Diseases, Emerging , Vaccines, DNA , Viral Vaccines , Animals , COVID-19 , Communicable Diseases, Emerging/prevention & control , Humans , Immunity , SARS Virus , SARS-CoV-2 , Vaccines, Attenuated/immunology , Vaccines, DNA/immunology , Vaccines, Inactivated/immunology , Vaccines, Synthetic/immunology , Viral Vaccines/genetics , Viral Vaccines/immunology
12.
J Virol ; 96(3): e0150421, 2022 02 09.
Article in English | MEDLINE | ID: covidwho-1546442

ABSTRACT

In the age of COVID, nucleic acid vaccines have garnered much attention, at least in part, because of the simplicity of construction, production, and flexibility to adjust and adapt to an evolving outbreak. Orthopoxviruses remain a threat on multiple fronts, especially as emerging zoonoses. In response, we developed a DNA vaccine, termed 4pox, that protected nonhuman primates against monkeypox virus (MPXV)-induced severe disease. Here, we examined the protective efficacy of the 4pox DNA vaccine delivered by intramuscular (i.m.) electroporation (EP) in rabbits challenged with aerosolized rabbitpox virus (RPXV), a model that recapitulates the respiratory route of exposure and low dose associated with natural smallpox exposure in humans. We found that 4pox-vaccinated rabbits developed immunogen-specific antibodies, including neutralizing antibodies, and did not develop any clinical disease, indicating protection against aerosolized RPXV. In contrast, unvaccinated animals developed significant signs of disease, including lesions, and were euthanized. These findings demonstrate that an unformulated, nonadjuvanted DNA vaccine delivered i.m. can protect against an aerosol exposure. IMPORTANCE The eradication of smallpox and subsequent cessation of vaccination have left a majority of the population susceptible to variola virus or other emerging poxviruses. This is exemplified by human monkeypox, as evidenced by the increase in reported endemic and imported cases over the past decades. Therefore, a malleable vaccine technology that can be mass produced and does not require complex conditions for distribution and storage is sought. Herein, we show that a DNA vaccine, in the absence of a specialized formulation or adjuvant, can protect against a lethal aerosol insult of rabbitpox virus.


Subject(s)
/immunology , Orthopoxvirus/immunology , Poxviridae Infections/prevention & control , Vaccinia virus/immunology , Vaccinia/prevention & control , Viral Proteins/immunology , Viral Vaccines/immunology , Animals , B-Lymphocytes/immunology , B-Lymphocytes/metabolism , Dose-Response Relationship, Immunologic , Electroporation , Female , Immunization/methods , Immunogenicity, Vaccine , Lymphocyte Activation/immunology , Oligodeoxyribonucleotides/administration & dosage , Oligodeoxyribonucleotides/immunology , Rabbits , Vaccines, DNA/immunology , Vaccinia virus/genetics , Viral Vaccines/administration & dosage
13.
Nat Commun ; 12(1): 6871, 2021 11 26.
Article in English | MEDLINE | ID: covidwho-1537309

ABSTRACT

Several effective SARS-CoV-2 vaccines are currently in use, but effective boosters are needed to maintain or increase immunity due to waning responses and the emergence of novel variants. Here we report that intranasal vaccinations with adenovirus 5 and 19a vectored vaccines following a systemic plasmid DNA or mRNA priming result in systemic and mucosal immunity in mice. In contrast to two intramuscular applications of an mRNA vaccine, intranasal boosts with adenoviral vectors induce high levels of mucosal IgA and lung-resident memory T cells (TRM); mucosal neutralization of virus variants of concern is also enhanced. The mRNA prime provokes a comprehensive T cell response consisting of circulating and lung TRM after the boost, while the plasmid DNA prime induces mostly mucosal T cells. Concomitantly, the intranasal boost strategies lead to complete protection against a SARS-CoV-2 infection in mice. Our data thus suggest that mucosal booster immunizations after mRNA priming is a promising approach to establish mucosal immunity in addition to systemic responses.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Immunity, Mucosal , Immunization, Secondary/methods , SARS-CoV-2/immunology , Adenoviridae/genetics , Administration, Intranasal , Animals , Antibodies, Viral/immunology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/genetics , Genetic Vectors , Immunization Schedule , Immunogenicity, Vaccine , Mice , Vaccines, DNA/administration & dosage , Vaccines, DNA/genetics , Vaccines, DNA/immunology , /immunology
14.
Curr Opin Immunol ; 71: 111-116, 2021 08.
Article in English | MEDLINE | ID: covidwho-1531148

ABSTRACT

COVID-19 is a pandemic of unprecedented proportions in recent human history. Less than 18 months since the onset of the pandemic, there are close to two hundred million confirmed cases and four million deaths worldwide. There have also been massive efforts geared towards finding safe and effective vaccines. By July 2021 there were 184 COVID-19 vaccine candidates in pre-clinical development, 105 in clinical development, and 18 vaccines approved for emergency use by at least one regulatory authority. These vaccines include whole virus live attenuated or inactivated, protein-based, viral vector, and nucleic acid vaccines. By mid-2021 three billion doses of COVID-19 vaccine have been administered around the world, mostly in high-income countries. COVID-19 vaccination provides hope for an end to the pandemic, if and only if there would be equal access and optimal uptake in all countries around the world.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/immunology , COVID-19/prevention & control , Humans , Pandemics/prevention & control , SARS-CoV-2/immunology , Vaccines, DNA/immunology , Vaccines, Inactivated/immunology
15.
Nat Biotechnol ; 39(12): 1479-1482, 2021 12.
Article in English | MEDLINE | ID: covidwho-1521715
16.
Vaccine ; 39(49): 7175-7181, 2021 12 03.
Article in English | MEDLINE | ID: covidwho-1508202

ABSTRACT

The development of new, low-cost vaccines and effective gene therapies requires accurate delivery and high-level expression of candidate genes. We developed a plasmid vector, pIDV-II, that allows for both easy manipulation and high expression of exogenous genes in mammalian cells. This plasmid is based upon the pVax1 plasmid and shares a common structure with typical mammalian transcription units. It is composed of a chicken ß-actin promoter (CAG), followed by an intron and flanked by two restriction sites, and also includes a post-transcriptional regulatory element, followed by a transcriptional termination signal. While the modification of pVax1 elements either decreased eGFP expression levels or had no effect at all, replacement of the promoter, the poly-A signal, deletion of the T7 and AmpR promoters, and inversion of the ORI-Neo/Kan cassette, significantly increased in vitro eGFP expression with the modified plasmid called pIDV-II. To further evaluate our vector, expression levels of three viral antigens were compared in cell lines transfected either with pVax1 or pCAGGS backbones as controls. Higher transgene expression was consistently observed with pIDV-II. The humoral and cellular responses generated in mice immunized with pIDV-II vs pVax1 expressing each viral antigen individually were superior by 2-fold or more as measured by ELISA and ELISPOT assays. Overall these results indicate that pIDV-II induces robust transgene expression, with concomitant improved cellular and humoral immune responses against the transgene of interest over pVax1. The new vector, pIDV-II, offers an additional alternative for DNA based vaccination and gene therapy for animal and human use.


Subject(s)
Vaccines, DNA , Animals , DNA , Immunity, Humoral , Mice , Mice, Inbred BALB C , Transgenes , Vaccines, DNA/genetics
17.
Sci Adv ; 7(45): eabj0611, 2021 11 05.
Article in English | MEDLINE | ID: covidwho-1515256

ABSTRACT

This work reports a suction-based cutaneous delivery method for in vivo DNA transfection. Following intradermal Mantoux injection of plasmid DNA in a rat model, a moderate negative pressure is applied to the injection site, a technique similar to Chinese báguàn and Middle Eastern hijama cupping therapies. Strong GFP expression was demonstrated with pEGFP-N1 plasmids where fluorescence was observed as early as 1 hour after dosing. Modeling indicates a strong correlation between focal strain/stress and expression patterns. The absence of visible and/or histological tissue injury contrasts with current in vivo transfection systems such as electroporation. Specific utility was demonstrated with a synthetic SARS-CoV-2 DNA vaccine, which generated host humoral immune response in rats with notable antibody production. This method enables an easy-to-use, cost-effective, and highly scalable platform for both laboratorial transfection needs and clinical applications for nucleic acid­based therapeutics and vaccines.


Subject(s)
COVID-19 Vaccines , COVID-19 , DNA , SARS-CoV-2 , Skin/immunology , Transfection , Vaccines, DNA , Administration, Cutaneous , Animals , COVID-19/genetics , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/genetics , COVID-19 Vaccines/immunology , COVID-19 Vaccines/pharmacology , DNA/genetics , DNA/immunology , DNA/pharmacology , Male , Rats , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Suction , Vaccines, DNA/genetics , Vaccines, DNA/immunology , Vaccines, DNA/pharmacology
18.
Lancet Microbe ; 3(1): e11-e20, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1505678

ABSTRACT

BACKGROUND: ChAdOx1-vectored vaccine candidates against several pathogens have been developed and tested in clinical trials and ChAdOx1 nCoV-19 has now been licensed for emergency use for COVID-19. We assessed the safety and immunogenicity of the ChAdOx1 MERS vaccine in a phase 1b trial in healthy Middle Eastern adults. METHOD: MERS002 is an open-label, non-randomised, dose-escalation, phase 1b trial. Healthy Middle Eastern adults aged 18-50 years were included in the study. ChAdOx1 MERS was administered as a single intramuscular injection into the deltoid muscle of the non-dominant arm at three different dose groups: 5·0 × 109 viral particles in a low-dose group, 2·5 × 1010 viral particles in an intermediate-dose group, and 5·0 × 1010 viral particles in a high-dose group. The primary objective was to assess the safety and tolerability of ChAdOx1 MERS, measured by the occurrence of solicited and unsolicited adverse events after vaccination for up to 28 days and occurrence of serious adverse events up to 6 months. The study is registered with ClinicalTrials.gov, NCT04170829. FINDINGS: Between Dec 17, 2019, and June 1, 2020, 24 participants were enrolled (six to the low-dose, nine to the intermediate-dose, and nine to the high-dose group) and received a dose; 23 were available for follow-up at 6 months. The one dose of ChAdOx1 MERS vaccine was well tolerated with no serious adverse event reported during the 6 months of follow-up. Most adverse events were mild (67, 74%) and moderate (17, 19%). Six (7%) severe adverse events were reported by two participants in the intermediate-dose group (two feverish, two headache, one joint pain, and one muscle pain). Pain at the injection site was the most common local and overall adverse event, reported by 15 (63%) of the 24 participants. The most common systemic adverse event was headache, reported by 14 (58%), followed by muscle pain reported by 13 (54%). The vaccine induced both antibody and T cell immune responses in all volunteers; antibodies peaked at day 28 and T cell responses peaked at day 14; and continued until the end of follow-up at 6 months. INTERPRETATION: The acceptable safety and immunogenicity data from this phase 1b trial of ChAdOx1 MERS vaccine candidate in Healthy Middle Eastern adults, combined with previous safety and immunogenicity data from a trial in the UK, support selecting the ChAdOx1 MERS vaccine for advancement into phase 2 clinical evaluation. FUNDING: UK Department of Health and Social Care, using UK Aid funding, managed by the UK National Institute for Health Research; and King Abdullah International Medical Research Center.


Subject(s)
COVID-19 , Adult , Antibodies, Viral , COVID-19/prevention & control , Coronavirus Infections/prevention & control , Headache , Humans , Immunogenicity, Vaccine , Myalgia , Vaccines, DNA , Viral Vaccines
19.
Bioelectrochemistry ; 144: 107994, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1499650

ABSTRACT

Gene therapies are revolutionizing medicine by providing a way to cure hitherto incurable diseases. The scientific and technological advances have enabled the first gene therapies to become clinically approved. In addition, with the ongoing COVID-19 pandemic, we are witnessing record speeds in the development and distribution of gene-based vaccines. For gene therapy to take effect, the therapeutic nucleic acids (RNA or DNA) need to overcome several barriers before they can execute their function of producing a protein or silencing a defective or overexpressing gene. This includes the barriers of the interstitium, the cell membrane, the cytoplasmic barriers and (in case of DNA) the nuclear envelope. Gene electrotransfer (GET), i.e., transfection by means of pulsed electric fields, is a non-viral technique that can overcome these barriers in a safe and effective manner. GET has reached the clinical stage of investigations where it is currently being evaluated for its therapeutic benefits across a wide variety of indications. In this review, we formalize our current understanding of GET from a biophysical perspective and critically discuss the mechanisms by which electric field can aid in overcoming the barriers. We also identify the gaps in knowledge that are hindering optimization of GET in vivo.


Subject(s)
Electroporation , Gene Transfer Techniques , Genetic Therapy , Animals , COVID-19/prevention & control , Electroporation/instrumentation , Electroporation/methods , Equipment Design , Gene Transfer Techniques/instrumentation , Genetic Therapy/methods , Humans , Vaccines, DNA/administration & dosage , Vaccines, DNA/genetics , Vaccines, DNA/therapeutic use , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/therapeutic use , /genetics , /therapeutic use
20.
Proc Natl Acad Sci U S A ; 118(43)2021 10 26.
Article in English | MEDLINE | ID: covidwho-1481965

ABSTRACT

Self-amplifying RNA replicons are promising platforms for vaccine generation. Their defects in one or more essential functions for viral replication, particle assembly, or dissemination make them highly safe as vaccines. We previously showed that the deletion of the envelope (E) gene from the Middle East respiratory syndrome coronavirus (MERS-CoV) produces a replication-competent propagation-defective RNA replicon (MERS-CoV-ΔE). Evaluation of this replicon in mice expressing human dipeptidyl peptidase 4, the virus receptor, showed that the single deletion of the E gene generated an attenuated mutant. The combined deletion of the E gene with accessory open reading frames (ORFs) 3, 4a, 4b, and 5 resulted in a highly attenuated propagation-defective RNA replicon (MERS-CoV-Δ[3,4a,4b,5,E]). This RNA replicon induced sterilizing immunity in mice after challenge with a lethal dose of a virulent MERS-CoV, as no histopathological damage or infectious virus was detected in the lungs of challenged mice. The four mutants lacking the E gene were genetically stable, did not recombine with the E gene provided in trans during their passage in cell culture, and showed a propagation-defective phenotype in vivo. In addition, immunization with MERS-CoV-Δ[3,4a,4b,5,E] induced significant levels of neutralizing antibodies, indicating that MERS-CoV RNA replicons are highly safe and promising vaccine candidates.


Subject(s)
Coronavirus Infections/prevention & control , Middle East Respiratory Syndrome Coronavirus/genetics , Middle East Respiratory Syndrome Coronavirus/immunology , RNA, Viral/administration & dosage , Replicon , Viral Vaccines/administration & dosage , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/virology , Defective Viruses/genetics , Defective Viruses/immunology , Female , Gene Deletion , Genes, env , Humans , Mice , Mice, Inbred C57BL , Mice, Transgenic , Middle East Respiratory Syndrome Coronavirus/pathogenicity , RNA, Viral/genetics , RNA, Viral/immunology , Vaccines, DNA , Vaccines, Virus-Like Particle/administration & dosage , Vaccines, Virus-Like Particle/genetics , Vaccines, Virus-Like Particle/immunology , Viral Vaccines/genetics , Viral Vaccines/immunology , Virulence/genetics , Virulence/immunology
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