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1.
NPJ Vaccines ; 6(1): 156, 2021 Dec 20.
Article in English | MEDLINE | ID: covidwho-1585846

ABSTRACT

New generation plasmid DNA vaccines may be a safe, fast and simple emergency vaccine platform for preparedness against emerging viral pathogens. Applying platform optimization strategies, we tested the pre-clinical immunogenicity and protective effect of a candidate DNA plasmid vaccine specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The DNA vaccine induced spike-specific binding IgG and neutralizing antibodies in mice, rabbits, and rhesus macaques together with robust Th1 dominant cellular responses in small animals. Intradermal and intramuscular needle-free administration of the DNA vaccine yielded comparable immune responses. In a vaccination-challenge study of rhesus macaques, the vaccine demonstrated protection from viral replication in the lungs following intranasal and intratracheal inoculation with SARS-CoV-2. In conclusion, the candidate plasmid DNA vaccine encoding the SARS-CoV-2 spike protein is immunogenic in different models and confers protection against lung infection in nonhuman primates. Further evaluation of this DNA vaccine candidate in clinical trials is warranted.

2.
JCI Insight ; 6(10)2021 04 28.
Article in English | MEDLINE | ID: covidwho-1206097

ABSTRACT

Effective SARS-CoV-2 vaccines are urgently needed. Although most vaccine strategies have focused on systemic immunization, here we compared the protective efficacy of 2 adjuvanted subunit vaccines with spike protein S1: an intramuscularly primed/boosted vaccine and an intramuscularly primed/intranasally boosted mucosal vaccine in rhesus macaques. The intramuscular-alum-only vaccine induced robust binding and neutralizing antibody and persistent cellular immunity systemically and mucosally, whereas intranasal boosting with nanoparticles, including IL-15 and TLR agonists, elicited weaker T cell and Ab responses but higher dimeric IgA and IFN-α. Nevertheless, following SARS-CoV-2 challenge, neither group showed detectable subgenomic RNA in upper or lower respiratory tracts versus naive controls, indicating full protection against viral replication. Although mucosal and systemic protective mechanisms may differ, results demonstrate both vaccines can protect against respiratory SARS-CoV-2 exposure. In summary, we have demonstrated that the mucosal vaccine was safe after multiple doses and cleared the input virus more efficiently in the nasal cavity and thus may act as a potent complementary reinforcing boost for conventional systemic vaccines to provide overall better protection.


Subject(s)
COVID-19 Vaccines/therapeutic use , COVID-19/veterinary , Macaca mulatta/immunology , SARS-CoV-2/immunology , Adaptive Immunity , Animals , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/pathology , COVID-19/prevention & control , Humans , Immunity, Cellular , Immunity, Humoral , Vaccines, Subunit/therapeutic use
3.
Immunity ; 53(4): 724-732.e7, 2020 10 13.
Article in English | MEDLINE | ID: covidwho-710374

ABSTRACT

SARS-CoV-2 infection has emerged as a serious global pandemic. Because of the high transmissibility of the virus and the high rate of morbidity and mortality associated with COVID-19, developing effective and safe vaccines is a top research priority. Here, we provide a detailed evaluation of the immunogenicity of lipid nanoparticle-encapsulated, nucleoside-modified mRNA (mRNA-LNP) vaccines encoding the full-length SARS-CoV-2 spike protein or the spike receptor binding domain in mice. We demonstrate that a single dose of these vaccines induces strong type 1 CD4+ and CD8+ T cell responses, as well as long-lived plasma and memory B cell responses. Additionally, we detect robust and sustained neutralizing antibody responses and the antibodies elicited by nucleoside-modified mRNA vaccines do not show antibody-dependent enhancement of infection in vitro. Our findings suggest that the nucleoside-modified mRNA-LNP vaccine platform can induce robust immune responses and is a promising candidate to combat COVID-19.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Betacoronavirus/drug effects , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , RNA, Messenger/immunology , RNA, Viral/immunology , Viral Vaccines/administration & dosage , Animals , B-Lymphocytes/drug effects , B-Lymphocytes/immunology , B-Lymphocytes/virology , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , CD4-Positive T-Lymphocytes/drug effects , CD4-Positive T-Lymphocytes/immunology , CD4-Positive T-Lymphocytes/virology , CD8-Positive T-Lymphocytes/drug effects , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/virology , COVID-19 , COVID-19 Vaccines , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Disease Models, Animal , Furin/genetics , Furin/immunology , Humans , Immunity, Humoral/drug effects , Immunization/methods , Immunogenicity, Vaccine , Immunologic Memory/drug effects , Lymphocyte Activation/drug effects , Mice , Mice, Inbred BALB C , Nanoparticles/administration & dosage , Nanoparticles/chemistry , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , RNA, Messenger/genetics , RNA, Viral/genetics , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vaccines, Synthetic , Viral Vaccines/biosynthesis , Viral Vaccines/genetics
4.
N Engl J Med ; 383(16): 1544-1555, 2020 10 15.
Article in English | MEDLINE | ID: covidwho-680559

ABSTRACT

BACKGROUND: Vaccines to prevent coronavirus disease 2019 (Covid-19) are urgently needed. The effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines on viral replication in both upper and lower airways is important to evaluate in nonhuman primates. METHODS: Nonhuman primates received 10 or 100 µg of mRNA-1273, a vaccine encoding the prefusion-stabilized spike protein of SARS-CoV-2, or no vaccine. Antibody and T-cell responses were assessed before upper- and lower-airway challenge with SARS-CoV-2. Active viral replication and viral genomes in bronchoalveolar-lavage (BAL) fluid and nasal swab specimens were assessed by polymerase chain reaction, and histopathological analysis and viral quantification were performed on lung-tissue specimens. RESULTS: The mRNA-1273 vaccine candidate induced antibody levels exceeding those in human convalescent-phase serum, with live-virus reciprocal 50% inhibitory dilution (ID50) geometric mean titers of 501 in the 10-µg dose group and 3481 in the 100-µg dose group. Vaccination induced type 1 helper T-cell (Th1)-biased CD4 T-cell responses and low or undetectable Th2 or CD8 T-cell responses. Viral replication was not detectable in BAL fluid by day 2 after challenge in seven of eight animals in both vaccinated groups. No viral replication was detectable in the nose of any of the eight animals in the 100-µg dose group by day 2 after challenge, and limited inflammation or detectable viral genome or antigen was noted in lungs of animals in either vaccine group. CONCLUSIONS: Vaccination of nonhuman primates with mRNA-1273 induced robust SARS-CoV-2 neutralizing activity, rapid protection in the upper and lower airways, and no pathologic changes in the lung. (Funded by the National Institutes of Health and others.).


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/immunology , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , 2019-nCoV Vaccine mRNA-1273 , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/physiology , CD4 Antigens , COVID-19 , COVID-19 Vaccines , Coronavirus Infections/pathology , Coronavirus Infections/therapy , Disease Models, Animal , Dose-Response Relationship, Immunologic , Immunization, Passive , Lung/pathology , Lung/virology , Macaca mulatta , Pneumonia, Viral/pathology , Pneumonia, Viral/therapy , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , T-Lymphocytes/immunology , Viral Load , Viral Vaccines/administration & dosage , Virus Replication
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