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1.
Signal Transduct Target Ther ; 7(1): 114, 2022 Apr 05.
Article in English | MEDLINE | ID: covidwho-1778593

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel coronavirus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor-binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo. Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.


Subject(s)
Antibodies, Monoclonal , Antibodies, Viral , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Antibodies, Monoclonal/chemistry , Antibodies, Viral/chemistry , COVID-19 , Cryoelectron Microscopy , Humans , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology
2.
Signal Transduct Target Ther ; 7(1): 7, 2022 01 04.
Article in English | MEDLINE | ID: covidwho-1606287

ABSTRACT

Activation-induced cytidine deaminase (AID) initiates class-switch recombination and somatic hypermutation (SHM) in antibody genes. Protein expression and activity are tightly controlled by various mechanisms. However, it remains unknown whether a signal from the extracellular environment directly affects the AID activity in the nucleus where it works. Here, we demonstrated that a deubiquitinase USP10, which specifically stabilizes nuclear AID protein, can translocate into the nucleus after AKT-mediated phosphorylation at its T674 within the NLS domain. Interestingly, the signals from BCR and TLR1/2 synergistically promoted this phosphorylation. The deficiency of USP10 in B cells significantly decreased AID protein levels, subsequently reducing neutralizing antibody production after immunization with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or human immunodeficiency virus type 1 (HIV-1) nanoparticle vaccines. Collectively, we demonstrated that USP10 functions as an integrator for both BCR and TLR signals and directly regulates nuclear AID activity. Its manipulation could be used for the development of vaccines and adjuvants.


Subject(s)
AIDS Vaccines/immunology , B-Cell Activating Factor/immunology , COVID-19 Vaccines/immunology , Cytidine Deaminase/immunology , HIV-1/immunology , Nanoparticles , SARS-CoV-2/immunology , Signal Transduction/immunology , Ubiquitin Thiolesterase/immunology , Ubiquitination/immunology , AIDS Vaccines/genetics , Animals , B-Cell Activating Factor/genetics , COVID-19 Vaccines/genetics , Cytidine Deaminase/genetics , HEK293 Cells , HIV-1/genetics , Humans , Mice , Mice, Knockout , SARS-CoV-2/genetics , Signal Transduction/genetics , Ubiquitin Thiolesterase/genetics
3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-293463

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel corona virus disease (COVID-19). The neutralizing monoclonal antibodies (mAbs) targeting the receptor binding domain (RBD) of SARS-CoV-2 are among the most promising strategies to prevent and treat COVID-19. However, SARS-CoV-2 variants of concern (VOCs) profoundly reduced the efficacies of most of mAbs and vaccines approved for clinical use. Herein, we demonstrated mAb 35B5 efficiently neutralizes both wild-type (WT) SARS-CoV-2 and VOCs, including B.1.617.2 (delta) variant, in vitro and in vivo . Cryo-electron microscopy (cryo-EM) revealed that 35B5 neutralizes SARS-CoV-2 by targeting a unique epitope that avoids the prevailing mutation sites on RBD identified in circulating VOCs, providing the molecular basis for its pan-neutralizing efficacy. The 35B5-binding epitope could also be exploited for the rational design of a universal SARS-CoV-2 vaccine.

4.
Proc Natl Acad Sci U S A ; 118(23)2021 06 08.
Article in English | MEDLINE | ID: covidwho-1238060

ABSTRACT

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic and has claimed over 2 million lives worldwide. Although the genetic sequences of SARS-CoV and SARS-CoV-2 have high homology, the clinical and pathological characteristics of COVID-19 differ significantly from those of SARS. How and whether SARS-CoV-2 evades (cellular) immune surveillance requires further elucidation. In this study, we show that SARS-CoV-2 infection leads to major histocompability complex class Ι (MHC-Ι) down-regulation both in vitro and in vivo. The viral protein encoded by open reading frame 8 (ORF8) of SARS-CoV-2, which shares the least homology with SARS-CoV among all viral proteins, directly interacts with MHC-Ι molecules and mediates their down-regulation. In ORF8-expressing cells, MHC-Ι molecules are selectively targeted for lysosomal degradation via autophagy. Thus, SARS-CoV-2-infected cells are much less sensitive to lysis by cytotoxic T lymphocytes. Because ORF8 protein impairs the antigen presentation system, inhibition of ORF8 could be a strategy to improve immune surveillance.


Subject(s)
Antigen Presentation , COVID-19/immunology , Down-Regulation/immunology , Histocompatibility Antigens Class I/immunology , Immune Evasion , SARS-CoV-2/immunology , Viral Proteins/immunology , Animals , Autophagy/genetics , Autophagy/immunology , COVID-19/genetics , Chlorocebus aethiops , HEK293 Cells , Histocompatibility Antigens Class I/genetics , Humans , Lysosomes/genetics , Lysosomes/immunology , Lysosomes/virology , Mice , Mice, Transgenic , SARS-CoV-2/genetics , Vero Cells , Viral Proteins/genetics
5.
Signal Transduct Target Ther ; 6(1): 189, 2021 05 12.
Article in English | MEDLINE | ID: covidwho-1226420

ABSTRACT

Since the outbreak of coronavirus disease 2019 (COVID-19), it has become a global pandemic. The spike (S) protein of etiologic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) specifically recognizes human angiotensin-converting enzyme 2 (hACE2) as its receptor, which is recently identified as an interferon (IFN)-stimulated gene. Here, we find that hACE2 exists on the surface of exosomes released by different cell types, and the expression of exosomal hACE2 is increased by IFNα/ß treatment. In particular, exosomal hACE2 can specifically block the cell entry of SARS-CoV-2, subsequently inhibit the replication of SARS-CoV-2 in vitro and ex vivo. Our findings have indicated that IFN is able to upregulate a viral receptor on the exosomes which competitively block the virus entry, exhibiting a potential antiviral strategy.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Exosomes/metabolism , Interferon-alpha/pharmacology , Interferon-beta/pharmacology , SARS-CoV-2/physiology , Virus Internalization/drug effects , Virus Replication/drug effects , Angiotensin-Converting Enzyme 2/genetics , Animals , Chlorocebus aethiops , Exosomes/genetics , Exosomes/virology , HEK293 Cells , Humans , Mice , Mice, Transgenic , Vero Cells
6.
mBio ; 12(1)2021 01 19.
Article in English | MEDLINE | ID: covidwho-1066818

ABSTRACT

The etiologic agent of COVID-19 is highly contagious and has caused a severe global pandemic. Until now, there has been no simple and reliable system available in a lower-biosafety-grade laboratory for SARS-CoV-2 virologic research and inhibitor screening. In this study, we reported a replicon system which consists of four plasmids expressing the required segments of SARS-CoV-2. Our study revealed that the features for viral RNA synthesis and responses to antivirus drugs of the replicon are similar to those of wild-type viruses. Further analysis indicated that ORF6 provided potent in trans stimulation of the viral replication. Some viral variations, such as 5'UTR-C241T and ORF8-(T28144C) L84S mutation, also exhibit their different impact upon viral replication. Besides, the screening of clinically used drugs identified that several tyrosine kinase inhibitors and DNA-Top II inhibitors potently inhibit the replicon, as well as authentic SARS-CoV-2 viruses. Collectively, this replicon system provides a biosafety-worry-free platform for studying SARS-CoV-2 virology, monitoring the functional impact of viral mutations, and developing viral inhibitors.IMPORTANCE COVID-19 has caused a severe global pandemic. Until now, there has been no simple and reliable system available in a lower-biosafety-grade laboratory for SARS-CoV-2 virologic research and inhibitor screening. We reported a replicon system which consists of four ordinary plasmids expressing the required segments of SARS-CoV-2. Using the replicon system, we developed three application scenarios: (i) to identify the effects of viral proteins on virus replication, (ii) to identify the effects of mutations on viral replication during viral epidemics, and (iii) to perform high-throughput screening of antiviral drugs. Collectively, this replicon system would be useful for virologists to study SARS-CoV-2 virology, for epidemiologists to monitor virus mutations, and for industry to develop antiviral drugs.


Subject(s)
Antiviral Agents/pharmacology , COVID-19/virology , RNA, Viral/biosynthesis , Replicon/drug effects , SARS-CoV-2/drug effects , SARS-CoV-2/genetics , Drug Evaluation, Preclinical/methods , Female , Genetic Engineering , HEK293 Cells , High-Throughput Screening Assays , Humans , Inhibitory Concentration 50 , Mutation , Pandemics , RNA, Viral/genetics , Replicon/genetics , SARS-CoV-2/metabolism , Virus Replication/drug effects
7.
Immunity ; 53(6): 1315-1330.e9, 2020 12 15.
Article in English | MEDLINE | ID: covidwho-967948

ABSTRACT

Various vaccine strategies have been proposed in response to the global COVID-19 pandemic, each with unique strategies for eliciting immune responses. Here, we developed nanoparticle vaccines by covalently conjugating the self-assembled 24-mer ferritin to the receptor binding domain (RBD) and/or heptad repeat (HR) subunits of the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) spike (S) protein. Compared to monomer vaccines, nanoparticle vaccines elicited more robust neutralizing antibodies and cellular immune responses. RBD and RBD-HR nanoparticle vaccinated hACE2 transgenic mice vaccinated with RBD and/or RBD-HR nanoparticles exhibited reduced viral load in the lungs after SARS-CoV-2 challenge. RBD-HR nanoparticle vaccines also promoted neutralizing antibodies and cellular immune responses against other coronaviruses. The nanoparticle vaccination of rhesus macaques induced neutralizing antibodies, and T and B cell responses prior to boost immunization; these responses persisted for more than three months. RBD- and HR-based nanoparticles thus present a promising vaccination approach against SARS-CoV-2 and other coronaviruses.


Subject(s)
Bacterial Proteins/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Ferritins/immunology , Helicobacter pylori/metabolism , Recombinant Fusion Proteins/immunology , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/genetics , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , Bacterial Proteins/chemistry , COVID-19 Vaccines/chemistry , Ferritins/chemistry , Humans , Macaca mulatta , Mice , Mice, Inbred BALB C , Nanoparticles/chemistry , Pandemics , Protein Binding , Spike Glycoprotein, Coronavirus/chemistry , Vaccination
8.
Cell Mol Immunol ; 17(10): 1098-1100, 2020 10.
Article in English | MEDLINE | ID: covidwho-772968
9.
Signal Transduct Target Ther ; 5(1): 180, 2020 09 02.
Article in English | MEDLINE | ID: covidwho-744367

ABSTRACT

COVID-19 patients exhibit differential disease severity after SARS-CoV-2 infection. It is currently unknown as to the correlation between the magnitude of neutralizing antibody (NAb) responses and the disease severity in COVID-19 patients. In a cohort of 59 recovered patients with disease severity including severe, moderate, mild, and asymptomatic, we observed the positive correlation between serum neutralizing capacity and disease severity, in particular, the highest NAb capacity in sera from the patients with severe disease, while a lack of ability of asymptomatic patients to mount competent NAbs. Furthermore, the compositions of NAb subtypes were also different between recovered patients with severe symptoms and with mild-to-moderate symptoms. These results reveal the tremendous heterogeneity of SARS-CoV-2-specific NAb responses and their correlations to disease severity, highlighting the needs of future vaccination in COVID-19 patients recovered from asymptomatic or mild illness.


Subject(s)
Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Betacoronavirus/immunology , Coronavirus Infections/immunology , Coronavirus Infections/pathology , Pneumonia, Viral/immunology , Pneumonia, Viral/pathology , Adult , Betacoronavirus/pathogenicity , COVID-19 , Case-Control Studies , Convalescence , Coronavirus Infections/blood , Coronavirus Infections/virology , Female , Humans , Male , Middle Aged , Neutralization Tests , Pandemics , Pneumonia, Viral/blood , Pneumonia, Viral/virology , SARS-CoV-2 , Severity of Illness Index
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