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1.
Cell Reports ; : 110799, 2022.
Article in English | ScienceDirect | ID: covidwho-1800157

ABSTRACT

SUMMARY Although vaccines and monoclonal antibody countermeasures have reduced the morbidity and mortality associated with SARS-CoV-2 infection, variants with constellations of mutations in the spike gene jeopardize their efficacy. Accordingly, antiviral interventions that are resistant to further virus evolution are needed. The host-derived cytokine IFN-λ has been proposed as a possible treatment based on studies in human COVID-19 patients. Here, we show IFN-λ protects against SARS-CoV-2 B.1.351 (Beta) and B.1.1.529 (Omicron) variants in three strains of conventional and human ACE2 transgenic mice. Prophylaxis or therapy with nasally-delivered IFN-λ2 limited infection of historical or variant SARS-CoV-2 strains in the upper and lower respiratory tracts without causing excessive inflammation. In the lung, IFN-λ was produced preferentially in epithelial cells and acted on radio-resistant cells to protect against of SARS-CoV-2 infection. Thus, inhaled IFN-λ may have promise as a treatment for evolving SARS-CoV-2 variants that develop resistance to antibody-based countermeasures.

2.
J Virol ; 96(1): e0151121, 2022 01 12.
Article in English | MEDLINE | ID: covidwho-1621995

ABSTRACT

The development of mouse models for coronavirus disease 2019 (COVID-19) has enabled testing of vaccines and therapeutics and defining aspects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pathogenesis. SARS-CoV-2 disease is severe in K18 transgenic mice (K18-hACE2 Tg) expressing human angiotensin-converting enzyme 2 (hACE2), the SARS-CoV-2 receptor, under an ectopic cytokeratin promoter, with high levels of infection measured in the lung and brain. Here, we evaluated SARS-CoV-2 infection in hACE2 knock-in (KI) mice that express hACE2 under an endogenous promoter in place of murine ACE2 (mACE2). Intranasal inoculation of hACE2 KI mice with SARS-CoV-2 WA1/2020 resulted in substantial viral replication within the upper and lower respiratory tracts with limited spread to extrapulmonary organs. However, SARS-CoV-2-infected hACE2 KI mice did not lose weight and developed limited pathology. Moreover, no significant differences in viral burden were observed in hACE2 KI mice infected with B.1.1.7 or B.1.351 variants compared to the WA1/2020 strain. Because the entry mechanisms of SARS-CoV-2 in mice remain uncertain, we evaluated the impact of the naturally occurring, mouse-adapting N501Y mutation by comparing infection of hACE2 KI, K18-hACE2 Tg, ACE2-deficient, and wild-type C57BL/6 mice. The N501Y mutation minimally affected SARS-CoV-2 infection in hACE2 KI mice but was required for viral replication in wild-type C57BL/6 mice in a mACE2-dependent manner and augmented pathogenesis in the K18-hACE2 Tg mice. Thus, the N501Y mutation likely enhances interactions with mACE2 or hACE2 in vivo. Overall, our study highlights the hACE2 KI mice as a model of mild SARS-CoV-2 infection and disease and clarifies the requirement of the N501Y mutation in mice. IMPORTANCE Mouse models of SARS-CoV-2 pathogenesis have facilitated the rapid evaluation of countermeasures. While the first generation of models developed pneumonia and severe disease after SARS-CoV-2 infection, they relied on ectopic expression of supraphysiological levels of human ACE2 (hACE2). This has raised issues with their relevance to humans, as the hACE2 receptor shows a more restricted expression pattern in the respiratory tract. Here, we evaluated SARS-CoV-2 infection and disease with viruses containing or lacking a key mouse-adapting mutation in the spike gene in hACE2 KI mice, which express hACE2 under an endogenous promoter in place of murine ACE2. While infection of hACE2 KI mice with multiple strains of SARS-CoV-2 including variants of concern resulted in viral replication within the upper and lower respiratory tracts, the animals did not sustain severe lung injury. Thus, hACE2 KI mice serve as a model of mild infection with both ancestral and emerging SARS-CoV-2 variant strains.


Subject(s)
Angiotensin-Converting Enzyme 2/genetics , COVID-19/virology , Lung/virology , SARS-CoV-2/pathogenicity , Angiotensin-Converting Enzyme 2/metabolism , Animals , COVID-19/pathology , Disease Models, Animal , Gene Expression , Gene Knock-In Techniques , Humans , Inflammation , Lung/metabolism , Lung/pathology , Mice , Mice, Transgenic , Mutation , SARS-CoV-2/genetics , Viral Load , Virus Replication
3.
Non-conventional in English | MEDLINE, Grey literature | ID: grc-750513

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of human infections and hundreds of thousands of deaths. Accordingly, an effective vaccine is of critical importance in mitigating coronavirus induced disease 2019 (COVID-19) and curtailing the pandemic. We developed a replication-competent vesicular stomatitis virus (VSV)-based vaccine by introducing a modified form of the SARS-CoV-2 spike gene in place of the native glycoprotein gene (VSV-eGFP-SARS-CoV-2). Immunization of mice with VSV-eGFP-SARS-CoV-2 elicits high titers of antibodies that neutralize SARS-CoV-2 infection and target the receptor binding domain that engages human angiotensin converting enzyme-2 (ACE2). Upon challenge with a human isolate of SARS-CoV-2, mice expressing human ACE2 and immunized with VSV-eGFP-SARS-CoV-2 show profoundly reduced viral infection and inflammation in the lung indicating protection against pneumonia. Finally, passive transfer of sera from VSV-eGFP-SARS-CoV-2-immunized animals protects naïve mice from SARS-CoV-2 challenge. These data support development of VSV-eGFP-SARS-CoV-2 as an attenuated, replication-competent vaccine against SARS-CoV-2.

4.
Non-conventional in English | [Unspecified Source], Grey literature | ID: grc-750512

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2) emerged in late 2019 and has spread worldwide resulting in the Coronavirus Disease 2019 (COVID-19) pandemic. Although animal models have been evaluated for SARS-CoV-2 infection, none have recapitulated the severe lung disease phenotypes seen in hospitalized human cases. Here, we evaluate heterozygous transgenic mice expressing the human ACE2 receptor driven by the epithelial cell cytokeratin-18 gene promoter (K18-hACE2) as a model of SARS-CoV-2 infection. Intranasal inoculation of SARS-CoV-2 in K18-hACE2 mice results in high levels of viral infection in lung tissues with additional spread to other organs. Remarkably, a decline in pulmonary function, as measured by static and dynamic tests of respiratory capacity, occurs 4 days after peak viral titer and correlates with an inflammatory response marked by infiltration into the lung of monocytes, neutrophils, and activated T cells resulting in pneumonia. Cytokine profiling and RNA sequencing analysis of SARS-CoV-2-infected lung tissues show a massively upregulated innate immune response with prominent signatures of NF-kB-dependent, type I and II interferon signaling, and leukocyte activation pathways. Thus, the K18-hACE2 model of SARS-CoV-2 infection recapitulates many features of severe COVID-19 infection in humans and can be used to define the mechanistic basis of lung disease and test immune and antiviral-based countermeasures.

6.
Immunity ; 54(10): 2399-2416.e6, 2021 10 12.
Article in English | MEDLINE | ID: covidwho-1364126

ABSTRACT

With the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with increased transmissibility and potential resistance, antibodies and vaccines with broadly inhibitory activity are needed. Here, we developed a panel of neutralizing anti-SARS-CoV-2 monoclonal antibodies (mAbs) that bound the receptor binding domain of the spike protein at distinct epitopes and blocked virus attachment to its host receptor, human angiotensin converting enzyme-2 (hACE2). Although several potently neutralizing mAbs protected K18-hACE2 transgenic mice against infection caused by ancestral SARS-CoV-2 strains, others induced escape variants in vivo or lost neutralizing activity against emerging strains. One mAb, SARS2-38, potently neutralized all tested SARS-CoV-2 variants of concern and protected mice against challenge by multiple SARS-CoV-2 strains. Structural analysis showed that SARS2-38 engaged a conserved epitope proximal to the receptor binding motif. Thus, treatment with or induction of neutralizing antibodies that bind conserved spike epitopes may limit the loss of potency of therapies or vaccines against emerging SARS-CoV-2 variants.


Subject(s)
Antibodies, Neutralizing/immunology , Epitopes/immunology , SARS-CoV-2/immunology , Amino Acid Motifs , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/therapeutic use , COVID-19/prevention & control , COVID-19/virology , Epitopes/chemistry , Epitopes/metabolism , Humans , Immunoglobulin Light Chains/chemistry , Immunoglobulin Light Chains/metabolism , Mice , Neutralization Tests , Protein Domains , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
7.
Cell Rep ; 36(8): 109604, 2021 08 24.
Article in English | MEDLINE | ID: covidwho-1347524

ABSTRACT

Unrelated individuals can produce genetically similar clones of antibodies, known as public clonotypes, which have been seen in responses to different infectious diseases, as well as healthy individuals. Here we identify 37 public clonotypes in memory B cells from convalescent survivors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or in plasmablasts from an individual after vaccination with mRNA-encoded spike protein. We identify 29 public clonotypes, including clones recognizing the receptor-binding domain (RBD) in the spike protein S1 subunit (including a neutralizing, angiotensin-converting enzyme 2 [ACE2]-blocking clone that protects in vivo) and others recognizing non-RBD epitopes that bind the S2 domain. Germline-revertant forms of some public clonotypes bind efficiently to spike protein, suggesting these common germline-encoded antibodies are preconfigured for avid recognition. Identification of large numbers of public clonotypes provides insight into the molecular basis of efficacy of SARS-CoV-2 vaccines and sheds light on the immune pressures driving the selection of common viral escape mutants.

8.
Cell Host Microbe ; 29(7): 1151-1161.e5, 2021 07 14.
Article in English | MEDLINE | ID: covidwho-1283986

ABSTRACT

Despite the introduction of public health measures and spike protein-based vaccines to mitigate the COVID-19 pandemic, SARS-CoV-2 infections and deaths continue to have a global impact. Previously, we used a structural design approach to develop picomolar range miniproteins targeting the SARS-CoV-2 spike receptor-binding domain. Here, we investigated the capacity of modified versions of one lead miniprotein, LCB1, to protect against SARS-CoV-2-mediated lung disease in mice. Systemic administration of LCB1-Fc reduced viral burden, diminished immune cell infiltration and inflammation, and completely prevented lung disease and pathology. A single intranasal dose of LCB1v1.3 reduced SARS-CoV-2 infection in the lung when given as many as 5 days before or 2 days after virus inoculation. Importantly, LCB1v1.3 protected in vivo against a historical strain (WA1/2020), an emerging B.1.1.7 strain, and a strain encoding key E484K and N501Y spike protein substitutions. These data support development of LCB1v1.3 for prevention or treatment of SARS-CoV-2 infection.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Protein Binding , SARS-CoV-2/immunology , Administration, Intranasal , Angiotensin-Converting Enzyme 2 , Animals , COVID-19/immunology , COVID-19 Vaccines/administration & dosage , Disease Models, Animal , Female , Humans , Lung/immunology , Male , Mice , Mice, Inbred C57BL , Pandemics/prevention & control , Serine C-Palmitoyltransferase , Spike Glycoprotein, Coronavirus/chemistry , Viral Load
9.
Nature ; 596(7870): 103-108, 2021 08.
Article in English | MEDLINE | ID: covidwho-1275940

ABSTRACT

Rapidly emerging SARS-CoV-2 variants jeopardize antibody-based countermeasures. Although cell culture experiments have demonstrated a loss of potency of several anti-spike neutralizing antibodies against variant strains of SARS-CoV-21-3, the in vivo importance of these results remains uncertain. Here we report the in vitro and in vivo activity of a panel of monoclonal antibodies (mAbs), which correspond to many in advanced clinical development by Vir Biotechnology, AbbVie, AstraZeneca, Regeneron and Lilly, against SARS-CoV-2 variant viruses. Although some individual mAbs showed reduced or abrogated neutralizing activity in cell culture against B.1.351, B.1.1.28, B.1.617.1 and B.1.526 viruses with mutations at residue E484 of the spike protein, low prophylactic doses of mAb combinations protected against infection by many variants in K18-hACE2 transgenic mice, 129S2 immunocompetent mice and hamsters, without the emergence of resistance. Exceptions were LY-CoV555 monotherapy and LY-CoV555 and LY-CoV016 combination therapy, both of which lost all protective activity, and the combination of AbbVie 2B04 and 47D11, which showed a partial loss of activity. When administered after infection, higher doses of several mAb cocktails protected in vivo against viruses with a B.1.351 spike gene. Therefore, many-but not all-of the antibody products with Emergency Use Authorization should retain substantial efficacy against the prevailing variant strains of SARS-CoV-2.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/pharmacology , Antibodies, Viral/therapeutic use , COVID-19/virology , Neutralization Tests , SARS-CoV-2/drug effects , SARS-CoV-2/immunology , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/pharmacology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , COVID-19/genetics , COVID-19/immunology , COVID-19/prevention & control , Chlorocebus aethiops , Female , Humans , Male , Mesocricetus/immunology , Mesocricetus/virology , Mice , Mice, Transgenic , Post-Exposure Prophylaxis , Pre-Exposure Prophylaxis , SARS-CoV-2/genetics , Serine Endopeptidases/genetics , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
10.
Immunity ; 54(6): 1290-1303.e7, 2021 06 08.
Article in English | MEDLINE | ID: covidwho-1237724

ABSTRACT

Dissecting the evolution of memory B cells (MBCs) against SARS-CoV-2 is critical for understanding antibody recall upon secondary exposure. Here, we used single-cell sequencing to profile SARS-CoV-2-reactive B cells in 38 COVID-19 patients. Using oligo-tagged antigen baits, we isolated B cells specific to the SARS-CoV-2 spike, nucleoprotein (NP), open reading frame 8 (ORF8), and endemic human coronavirus (HCoV) spike proteins. SARS-CoV-2 spike-specific cells were enriched in the memory compartment of acutely infected and convalescent patients several months post symptom onset. With severe acute infection, substantial populations of endemic HCoV-reactive antibody-secreting cells were identified and possessed highly mutated variable genes, signifying preexisting immunity. Finally, MBCs exhibited pronounced maturation to NP and ORF8 over time, especially in older patients. Monoclonal antibodies against these targets were non-neutralizing and non-protective in vivo. These findings reveal antibody adaptation to non-neutralizing intracellular antigens during infection, emphasizing the importance of vaccination for inducing neutralizing spike-specific MBCs.


Subject(s)
Antibodies, Viral/immunology , Antibody Formation/immunology , B-Lymphocytes/immunology , COVID-19/immunology , Host-Pathogen Interactions/immunology , Immunodominant Epitopes/immunology , SARS-CoV-2/immunology , Antibodies, Neutralizing/immunology , Antibody Formation/genetics , B-Lymphocytes/metabolism , Computational Biology/methods , Cross Reactions/immunology , Epitope Mapping , Female , Gene Expression Profiling , High-Throughput Nucleotide Sequencing , Host-Pathogen Interactions/genetics , Humans , Immunodominant Epitopes/genetics , Immunologic Memory , Male , Neutralization Tests , Single-Cell Analysis/methods , Spike Glycoprotein, Coronavirus/immunology , Transcriptome
11.
Cell ; 184(9): 2316-2331.e15, 2021 04 29.
Article in English | MEDLINE | ID: covidwho-1135277

ABSTRACT

Most human monoclonal antibodies (mAbs) neutralizing SARS-CoV-2 recognize the spike (S) protein receptor-binding domain and block virus interactions with the cellular receptor angiotensin-converting enzyme 2. We describe a panel of human mAbs binding to diverse epitopes on the N-terminal domain (NTD) of S protein from SARS-CoV-2 convalescent donors and found a minority of these possessed neutralizing activity. Two mAbs (COV2-2676 and COV2-2489) inhibited infection of authentic SARS-CoV-2 and recombinant VSV/SARS-CoV-2 viruses. We mapped their binding epitopes by alanine-scanning mutagenesis and selection of functional SARS-CoV-2 S neutralization escape variants. Mechanistic studies showed that these antibodies neutralize in part by inhibiting a post-attachment step in the infection cycle. COV2-2676 and COV2-2489 offered protection either as prophylaxis or therapy, and Fc effector functions were required for optimal protection. Thus, natural infection induces a subset of potent NTD-specific mAbs that leverage neutralizing and Fc-mediated activities to protect against SARS-CoV-2 infection using multiple functional attributes.


Subject(s)
Antibodies, Monoclonal/pharmacology , Antibodies, Neutralizing/pharmacology , Protective Agents/pharmacology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Animals , Binding, Competitive , COVID-19/immunology , COVID-19/virology , Chemokines/metabolism , Chlorocebus aethiops , HEK293 Cells , Humans , Immunoglobulin Fab Fragments/metabolism , Immunoglobulin G/metabolism , Lung/metabolism , Mice, Inbred C57BL , Models, Molecular , Mutagenesis/genetics , Neutralization Tests , Protein Domains , Vero Cells
12.
JACC Basic Transl Sci ; 6(4): 331-345, 2021 Apr.
Article in English | MEDLINE | ID: covidwho-1122096

ABSTRACT

There is ongoing debate as to whether cardiac complications of coronavirus disease-2019 (COVID-19) result from myocardial viral infection or are secondary to systemic inflammation and/or thrombosis. We provide evidence that cardiomyocytes are infected in patients with COVID-19 myocarditis and are susceptible to severe acute respiratory syndrome coronavirus 2. We establish an engineered heart tissue model of COVID-19 myocardial pathology, define mechanisms of viral pathogenesis, and demonstrate that cardiomyocyte severe acute respiratory syndrome coronavirus 2 infection results in contractile deficits, cytokine production, sarcomere disassembly, and cell death. These findings implicate direct infection of cardiomyocytes in the pathogenesis of COVID-19 myocardial pathology and provides a model system to study this emerging disease.

13.
Nat Med ; 27(4): 717-726, 2021 04.
Article in English | MEDLINE | ID: covidwho-1118812

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the global COVID-19 pandemic. Rapidly spreading SARS-CoV-2 variants may jeopardize newly introduced antibody and vaccine countermeasures. Here, using monoclonal antibodies (mAbs), animal immune sera, human convalescent sera and human sera from recipients of the BNT162b2 mRNA vaccine, we report the impact on antibody neutralization of a panel of authentic SARS-CoV-2 variants including a B.1.1.7 isolate, chimeric strains with South African or Brazilian spike genes and isogenic recombinant viral variants. Many highly neutralizing mAbs engaging the receptor-binding domain or N-terminal domain and most convalescent sera and mRNA vaccine-induced immune sera showed reduced inhibitory activity against viruses containing an E484K spike mutation. As antibodies binding to spike receptor-binding domain and N-terminal domain demonstrate diminished neutralization potency in vitro against some emerging variants, updated mAb cocktails targeting highly conserved regions, enhancement of mAb potency or adjustments to the spike sequences of vaccines may be needed to prevent loss of protection in vivo.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , SARS-CoV-2/immunology , Animals , COVID-19/prevention & control , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Cricetinae , Humans , Mice , Mutation , Neutralization Tests , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
14.
Virology ; 557: 70-85, 2021 05.
Article in English | MEDLINE | ID: covidwho-1108783

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged into the human population in late 2019 and caused the global COVID-19 pandemic. SARS-CoV-2 has spread to more than 215 countries and infected many millions of people. Despite the introduction of numerous governmental and public health measures to control disease spread, infections continue at an unabated pace, suggesting that effective vaccines and antiviral drugs will be required to curtail disease, end the pandemic, and restore societal norms. Here, we review the current developments in antibody and vaccine countermeasures to limit or prevent disease.


Subject(s)
Antibodies, Viral/biosynthesis , COVID-19 Vaccines/immunology , COVID-19/prevention & control , Pandemics , SARS-CoV-2/immunology , Animals , COVID-19/epidemiology , COVID-19/immunology , COVID-19/therapy , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/biosynthesis , Clinical Trials as Topic , Disease Models, Animal , Genetic Vectors/chemistry , Genetic Vectors/immunology , Humans , Immunity, Innate/drug effects , Immunization, Passive/methods , Immunogenicity, Vaccine , Patient Safety , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicity , Vaccines, Attenuated , Vaccines, DNA , Vaccines, Subunit , Vaccines, Virus-Like Particle/administration & dosage , Vaccines, Virus-Like Particle/biosynthesis , Vaccines, Virus-Like Particle/immunology
15.
Cell ; 184(7): 1804-1820.e16, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-1084553

ABSTRACT

SARS-CoV-2 has caused the global COVID-19 pandemic. Although passively delivered neutralizing antibodies against SARS-CoV-2 show promise in clinical trials, their mechanism of action in vivo is incompletely understood. Here, we define correlates of protection of neutralizing human monoclonal antibodies (mAbs) in SARS-CoV-2-infected animals. Whereas Fc effector functions are dispensable when representative neutralizing mAbs are administered as prophylaxis, they are required for optimal protection as therapy. When given after infection, intact mAbs reduce SARS-CoV-2 burden and lung disease in mice and hamsters better than loss-of-function Fc variant mAbs. Fc engagement of neutralizing antibodies mitigates inflammation and improves respiratory mechanics, and transcriptional profiling suggests these phenotypes are associated with diminished innate immune signaling and preserved tissue repair. Immune cell depletions establish that neutralizing mAbs require monocytes and CD8+ T cells for optimal clinical and virological benefit. Thus, potently neutralizing mAbs utilize Fc effector functions during therapy to mitigate lung infection and disease.


Subject(s)
Antibodies, Monoclonal , Antibodies, Neutralizing , Antibodies, Viral , CD8-Positive T-Lymphocytes , COVID-19 , Immunoglobulin Fc Fragments/immunology , Animals , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , CD8-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/immunology , CHO Cells , COVID-19/immunology , COVID-19/therapy , Chlorocebus aethiops , Cricetulus , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , SARS-CoV-2/immunology , Vero Cells , Viral Load
16.
Nature ; 591(7849): 293-299, 2021 03.
Article in English | MEDLINE | ID: covidwho-1046014

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-a new coronavirus that has led to a worldwide pandemic1-has a furin cleavage site (PRRAR) in its spike protein that is absent in other group-2B coronaviruses2. To explore whether the furin cleavage site contributes to infection and pathogenesis in this virus, we generated a mutant SARS-CoV-2 that lacks the furin cleavage site (ΔPRRA). Here we report that replicates of ΔPRRA SARS-CoV-2 had faster kinetics, improved fitness in Vero E6 cells and reduced spike protein processing, as compared to parental SARS-CoV-2. However, the ΔPRRA mutant had reduced replication in a human respiratory cell line and was attenuated in both hamster and K18-hACE2 transgenic mouse models of SARS-CoV-2 pathogenesis. Despite reduced disease, the ΔPRRA mutant conferred protection against rechallenge with the parental SARS-CoV-2. Importantly, the neutralization values of sera from patients with coronavirus disease 2019 (COVID-19) and monoclonal antibodies against the receptor-binding domain of SARS-CoV-2 were lower against the ΔPRRA mutant than against parental SARS-CoV-2, probably owing to an increased ratio of particles to plaque-forming units in infections with the former. Together, our results demonstrate a critical role for the furin cleavage site in infection with SARS-CoV-2 and highlight the importance of this site for evaluating the neutralization activities of antibodies.


Subject(s)
COVID-19/virology , Furin/metabolism , Mutation , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Sequence , Animals , Antibodies, Neutralizing/immunology , COVID-19/pathology , COVID-19/physiopathology , Cell Line , Chlorocebus aethiops , Cricetinae , Female , Humans , Lung Diseases/pathology , Lung Diseases/physiopathology , Lung Diseases/virology , Male , Mice , Mice, Transgenic , Models, Molecular , Mutant Proteins/chemistry , Mutant Proteins/genetics , Mutant Proteins/metabolism , Proteolysis , SARS-CoV-2/chemistry , SARS-CoV-2/metabolism , Serine Endopeptidases/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Vero Cells , Virus Replication/genetics
17.
Nat Immunol ; 21(11): 1327-1335, 2020 11.
Article in English | MEDLINE | ID: covidwho-728991

ABSTRACT

Although animal models have been evaluated for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, none have fully recapitulated the lung disease phenotypes seen in humans who have been hospitalized. Here, we evaluate transgenic mice expressing the human angiotensin I-converting enzyme 2 (ACE2) receptor driven by the cytokeratin-18 (K18) gene promoter (K18-hACE2) as a model of SARS-CoV-2 infection. Intranasal inoculation of SARS-CoV-2 in K18-hACE2 mice results in high levels of viral infection in lungs, with spread to other organs. A decline in pulmonary function occurs 4 days after peak viral titer and correlates with infiltration of monocytes, neutrophils and activated T cells. SARS-CoV-2-infected lung tissues show a massively upregulated innate immune response with signatures of nuclear factor-κB-dependent, type I and II interferon signaling, and leukocyte activation pathways. Thus, the K18-hACE2 model of SARS-CoV-2 infection shares many features of severe COVID-19 infection and can be used to define the basis of lung disease and test immune and antiviral-based countermeasures.


Subject(s)
Betacoronavirus/immunology , Coronavirus Infections/pathology , Immunity, Innate/immunology , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/pathology , Pneumonia/pathology , Angiotensin-Converting Enzyme 2 , Animals , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/immunology , Disease Models, Animal , Female , Humans , Interferon Type I/immunology , Interferon-gamma/immunology , Keratin-18/genetics , Leukocytes/immunology , Lymphocyte Activation/immunology , Male , Mice , Mice, Transgenic , Monocytes/immunology , NF-kappa B/immunology , Neutrophil Infiltration/immunology , Neutrophils/immunology , Pandemics , Pneumonia/genetics , Pneumonia/virology , Pneumonia, Viral/immunology , Promoter Regions, Genetic/genetics , SARS-CoV-2 , T-Lymphocytes/immunology , Vero Cells , Virus Replication/immunology
18.
Cell ; 183(1): 169-184.e13, 2020 10 01.
Article in English | MEDLINE | ID: covidwho-720448

ABSTRACT

The coronavirus disease 2019 pandemic has made deployment of an effective vaccine a global health priority. We evaluated the protective activity of a chimpanzee adenovirus-vectored vaccine encoding a prefusion stabilized spike protein (ChAd-SARS-CoV-2-S) in challenge studies with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mice expressing the human angiotensin-converting enzyme 2 receptor. Intramuscular dosing of ChAd-SARS-CoV-2-S induces robust systemic humoral and cell-mediated immune responses and protects against lung infection, inflammation, and pathology but does not confer sterilizing immunity, as evidenced by detection of viral RNA and induction of anti-nucleoprotein antibodies after SARS-CoV-2 challenge. In contrast, a single intranasal dose of ChAd-SARS-CoV-2-S induces high levels of neutralizing antibodies, promotes systemic and mucosal immunoglobulin A (IgA) and T cell responses, and almost entirely prevents SARS-CoV-2 infection in both the upper and lower respiratory tracts. Intranasal administration of ChAd-SARS-CoV-2-S is a candidate for preventing SARS-CoV-2 infection and transmission and curtailing pandemic spread.


Subject(s)
Coronavirus Infections/immunology , Immunogenicity, Vaccine , Pneumonia, Viral/immunology , Viral Vaccines/immunology , Adenoviridae/genetics , Administration, Intranasal , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , COVID-19 , COVID-19 Vaccines , Chlorocebus aethiops , Coronavirus Infections/pathology , Coronavirus Infections/prevention & control , Female , HEK293 Cells , Humans , Injections, Intramuscular , Mice , Mice, Inbred BALB C , Pandemics , Pneumonia, Viral/pathology , Respiratory Mucosa/immunology , Respiratory Mucosa/pathology , Respiratory Mucosa/virology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Vero Cells , Viral Vaccines/administration & dosage
19.
Cell Host Microbe ; 28(3): 465-474.e4, 2020 09 09.
Article in English | MEDLINE | ID: covidwho-710174

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of human infections, and an effective vaccine is critical to mitigate coronavirus-induced disease 2019 (COVID-19). Previously, we developed a replication-competent vesicular stomatitis virus (VSV) expressing a modified form of the SARS-CoV-2 spike gene in place of the native glycoprotein gene (VSV-eGFP-SARS-CoV-2). Here, we show that vaccination with VSV-eGFP-SARS-CoV-2 generates neutralizing immune responses and protects mice from SARS-CoV-2. Immunization of mice with VSV-eGFP-SARS-CoV-2 elicits high antibody titers that neutralize SARS-CoV-2 and target the receptor binding domain that engages human angiotensin-converting enzyme-2 (ACE2). Upon challenge with a human isolate of SARS-CoV-2, mice that expressed human ACE2 and were immunized with VSV-eGFP-SARS-CoV-2 show profoundly reduced viral infection and inflammation in the lung, indicating protection against pneumonia. Passive transfer of sera from VSV-eGFP-SARS-CoV-2-immunized animals also protects naive mice from SARS-CoV-2 challenge. These data support development of VSV-SARS-CoV-2 as an attenuated, replication-competent vaccine against SARS-CoV-2.


Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Vesicular stomatitis Indiana virus/genetics , Viral Vaccines/genetics , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Neutralizing/blood , Antibodies, Viral/blood , Betacoronavirus/immunology , Betacoronavirus/pathogenicity , COVID-19 , COVID-19 Vaccines , Chlorocebus aethiops , Coronavirus Infections/genetics , Coronavirus Infections/immunology , Coronavirus Infections/virology , Disease Models, Animal , Genetic Vectors , Green Fluorescent Proteins/genetics , Host Microbial Interactions/immunology , Humans , Lung/immunology , Lung/pathology , Lung/virology , Mice , Mice, Inbred BALB C , Mice, Transgenic , Peptidyl-Dipeptidase A/genetics , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Receptors, Virus/genetics , SARS-CoV-2 , Vaccines, Synthetic/genetics , Vaccines, Synthetic/immunology , Vaccines, Synthetic/pharmacology , Vero Cells , Vesicular stomatitis Indiana virus/immunology , Viral Vaccines/immunology , Viral Vaccines/pharmacology
20.
bioRxiv ; 2020 Jul 10.
Article in English | MEDLINE | ID: covidwho-663086

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of human infections and hundreds of thousands of deaths. Accordingly, an effective vaccine is of critical importance in mitigating coronavirus induced disease 2019 (COVID-19) and curtailing the pandemic. We developed a replication-competent vesicular stomatitis virus (VSV)-based vaccine by introducing a modified form of the SARS-CoV-2 spike gene in place of the native glycoprotein gene (VSV-eGFP-SARS-CoV-2). Immunization of mice with VSV-eGFP-SARS-CoV-2 elicits high titers of antibodies that neutralize SARS-CoV-2 infection and target the receptor binding domain that engages human angiotensin converting enzyme-2 (ACE2). Upon challenge with a human isolate of SARS-CoV-2, mice expressing human ACE2 and immunized with VSV-eGFP-SARS-CoV-2 show profoundly reduced viral infection and inflammation in the lung indicating protection against pneumonia. Finally, passive transfer of sera from VSV-eGFP-SARS-CoV-2-immunized animals protects naïve mice from SARS-CoV-2 challenge. These data support development of VSV-eGFP-SARS-CoV-2 as an attenuated, replication-competent vaccine against SARS-CoV-2.

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