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1.
Journal of Medical Virology ; n/a(n/a), 2022.
Article in English | Wiley | ID: covidwho-1802454

ABSTRACT

There is a potential risk for SARS-CoV-2 spread through human contact with seafood and the inanimate materials contaminated by the virus. In this study, we examined the stability of the virus in artificial seawater (ASW) and on the surface of selected materials. SARS-CoV-2 (3.75 log10 TCID50) in ASW at 22? maintained infectious about 3 days and at 4? the virus survived more than 7 days. It should be noticed that viable virus at high titer (5.50 log10 TCID50) may survive more than 20 days in ASW at 4? and for 7 days at 22?. SARS-CoV-2 on stainless steel and plastic bag maintained infectious for 3 days, and on non-woven fabric for 1 day at 22?. In addition, the virus remained infectious for 9 days on stainless steel and non-woven fabric, and on plastic bag for 12 days at 4?. It is important to highlight the role of inanimate material surfaces as a source of infection and the necessity for surface decontamination and disinfection.This article is protected by copyright. All rights reserved.

2.
Cell ; 185(8): 1389-1401.e18, 2022 Apr 14.
Article in English | MEDLINE | ID: covidwho-1788017

ABSTRACT

The effectiveness of SARS-CoV-2 vaccines and therapeutic antibodies have been limited by the continuous emergence of viral variants and by the restricted diffusion of antibodies from circulation into the sites of respiratory virus infection. Here, we report the identification of two highly conserved regions on the Omicron variant receptor-binding domain recognized by broadly neutralizing antibodies. Furthermore, we generated a bispecific single-domain antibody that was able to simultaneously and synergistically bind these two regions on a single Omicron variant receptor-binding domain as revealed by cryo-EM structures. We demonstrated that this bispecific antibody can be effectively delivered to lung via inhalation administration and exhibits exquisite neutralization breadth and therapeutic efficacy in mouse models of SARS-CoV-2 infections. Importantly, this study also deciphered an uncommon and highly conserved cryptic epitope within the spike trimeric interface that may have implications for the design of broadly protective SARS-CoV-2 vaccines and therapeutics.

4.
EBioMedicine ; 76: 103861, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1734342

ABSTRACT

BACKGROUND: Since late 2019, SARS-CoV-2 infection has resulted in COVID-19 accompanied by diverse clinical manifestations. However, the underlying mechanism of how SARS-CoV-2 interacts with host and develops multiple symptoms is largely unexplored. METHODS: Bioinformatics analysis determined the sequence similarity between SARS-CoV-2 and human genomes. Diverse fragments of SARS-CoV-2 genome containing Human Identical Sequences (HIS) were cloned into the lentiviral vector. HEK293T, MRC5 and HUVEC were infected with laboratory-packaged lentivirus or transfected with plasmids or antagomirs for HIS. Quantitative RT-PCR and chromatin immunoprecipitation assay detected gene expression and H3K27ac enrichment, respectively. UV-Vis spectroscopy assessed the interaction between HIS and their target locus. Enzyme-linked immunosorbent assay evaluated the hyaluronan (HA) levels of culture supernatant and plasma of COVID-19 patients. FINDINGS: Five short sequences (24-27 nt length) sharing identity between SARS-CoV-2 and human genome were identified. These RNA elements were highly conserved in primates. The genomic fragments containing HIS were predicted to form hairpin structures in silico similar to miRNA precursors. HIS may function through direct genomic interaction leading to activation of host enhancers, and upregulation of adjacent and distant genes, including cytokine genes and hyaluronan synthase 2 (HAS2). HIS antagomirs and Cas13d-mediated HIS degradation reduced HAS2 expression. Severe COVID-19 patients displayed decreased lymphocytes and elevated D-dimer, and C-reactive proteins, as well as increased plasma hyaluronan. Hymecromone inhibited hyaluronan production in vitro, and thus could be further investigated as a therapeutic option for preventing severe outcome in COVID-19 patients. INTERPRETATION: HIS of SARS-CoV-2 could promote COVID-19 progression by upregulating hyaluronan, providing novel targets for treatment. FUNDING: The National Key R&D Program of China (2018YFC1005004), Major Special Projects of Basic Research of Shanghai Science and Technology Commission (18JC1411101), and the National Natural Science Foundation of China (31872814, 32000505).


Subject(s)
Gene Regulatory Networks/genetics , Genome, Human , Hyaluronic Acid/metabolism , RNA, Viral/genetics , SARS-CoV-2/genetics , Antagomirs/metabolism , Argonaute Proteins/genetics , Base Sequence , COVID-19/pathology , COVID-19/virology , Cell Line , Disease Progression , Enhancer Elements, Genetic/genetics , Humans , Hyaluronan Synthases/genetics , Hyaluronan Synthases/metabolism , Hyaluronic Acid/blood , MicroRNAs/genetics , RNA, Viral/chemistry , SARS-CoV-2/isolation & purification , SARS-CoV-2/pathogenicity , Up-Regulation
6.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-324633

ABSTRACT

The receptor-binding domain (RBD) variants of SARS-CoV-2 could impair antibody-mediated neutralization of the virus by host immunity;thus, prospective surveillance for such antibody escape mutants is urgently needed. Here, we comprehensively profiled four antigenic sites of the RBD and mapped the binding hot spots for a panel of RBD-specific monoclonal antibodies isolated from COVID-19 convalescents, especially dominant VH3-53/3–66 antibodies, which are valuable indicators of antigenic changes in the RBD. We further demonstrated that several natural mutations, namely, K417N, F486L, N450K, L452R, E484K, F490S and R346S, significantly decreased the neutralizing activity of multiple human monoclonal antibodies and of human convalescent plasma obtained in the early stage of the COVID-19 pandemic. Of note, among the natural escape mutations, L452R enhanced ACE2 binding affinity, indicating that it potentially increased virulence. Overall, the in-depth maps may have far-reaching value for surveillance of SARS-CoV-2 immune escape variants and guidance of vaccine design.

7.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-315723

ABSTRACT

The pandemic of COVID-19 caused by SARS-CoV-2 has posed serious threats to global health and economy, thus calling for the development of safe and effective vaccines. The receptor-binding domain (RBD) in the spike protein of SARS-CoV-2 is responsible for its binding to ACE2 receptor. It contains multiple dominant neutralizing epitopes and serves as an important antigen for the development of COVID-19 vaccines. Here, we showed that immunization of mice with a candidate subunit vaccine consisting of SARS-CoV-2 RBD and Fc fragment of human IgG, as an immunopotentiator, elicited high titer of RBD-specific antibodies with robust neutralizing activity against both pseudotyped and live SARS-CoV-2 infections. The mouse antisera could also effectively neutralize infection by pseudotyped SARS-CoV-2 with several natural mutations in RBD and the IgG extracted from the mouse antisera could also show neutralization against pseudotyped SARS-CoV and SARS-related coronavirus (SARSr-CoV). Vaccination of human ACE2 transgenic mice with RBD-Fc could effectively protect mice from the SARS-CoV-2 challenge. These results suggest that SARS-CoV-2 RBD-Fc has good potential to be further developed as an effective and broad-spectrum vaccine to prevent infection of the current SARS-CoV-2 and its mutants, as well as future emerging SARSr-CoVs and re-emerging SARS-CoV.

8.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-313429

ABSTRACT

Accumulating mutations on SARS-CoV-2 Spike (S) protein may increase the possibility of immune escape, challenging the present COVID-19 prophylaxis and clinical interventions. Here, in a panel of receptor binding domain (S-RBD) specific monoclonal antibodies (mAbs) with high neutralizing potency against authentic SARS-CoV-2, at least 6 of them were found to efficiently block the pseudovirus of 501Y.V2, a highly transmissible SARS-CoV-2 variant with escape mutations. The top 3 neutralizing Abs (13G9, 58G6 and 510A5) exhibited comparative ultrapotency as those being actively pursued for clinical development. Interestingly, the antigenic sites for the majority of our neutralizing Abs overlapped with a single epitope (13G9e) on S-RBD. Further, the 3-dimensional structures of 2 ultrapotent neutralizing Abs 13G9 or 58G6 in complex with SARS-CoV-2 S trimer demonstrated that both Abs bound to a steric region within S 472–490 . Moreover, a specific linear region (S 450–457 ) was identified as an additional target for 58G6. Importantly, our cryo-electron microscopy (cryo-EM) analysis revealed a unique phenomenon that the S-RBDs interacting with the fragments of antigen binding (Fabs) of 13G9 or 58G6 encoded by the IGHV1-58 and the IGKV3-20 gene segments were universally in the ‘up’ conformation in all observed particles. The potent neutralizing Abs presented in the current study may be promising candidates to fulfill the urgent needs for the current pandemic of SARS-CoV-2, and may of fundamental value for the next-generation vaccine development.

9.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-311951

ABSTRACT

After the epidemic of COVID-19, neutralizing antibodies (NAbs) against SARS-CoV-2 has been developed for the preventative and therapeutic purposes. However, few methodologies are reported in detail on how to rapidly and efficiently generate NAbs of interest. Here, we present a strategically optimized screening method for NAbs, which has enabled us to obtain SARS-CoV-2 receptor-binding domain (RBD) specific monoclonal Abs within 4 days, followed by additional 2 days to evaluate their neutralizing activities. Using this method, we obtained 198 specific Abs against SARS-CoV-2 RBD from the blood samples of COVID-19 convalescent patients, and 96 of them showed neutralizing activity. At least 20% of these NAbs exhibited high neutralizing potency. The top 2 NAbs showed the half-maximal inhibitory concentration (IC50) to block authentic SARS-CoV-2 at 9.88 and 11.13 ng/ml, respectively. Altogether, our study provides a fundamental methodology for discovering NAbs with potential preventative and therapeutic value for emerging infectious diseases.

10.
Nat Biomed Eng ; 6(3): 276-285, 2022 03.
Article in English | MEDLINE | ID: covidwho-1671563

ABSTRACT

The detection of samples at ultralow concentrations (one to ten copies in 100 µl) in biofluids is hampered by the orders-of-magnitude higher amounts of 'background' biomolecules. Here we report a molecular system, immobilized on a liquid-gated graphene field-effect transistor and consisting of an aptamer probe bound to a flexible single-stranded DNA cantilever linked to a self-assembled stiff tetrahedral double-stranded DNA structure, for the rapid and ultrasensitive electromechanical detection (down to one to two copies in 100 µl) of unamplified nucleic acids in biofluids, and also of ions, small molecules and proteins, as we show for Hg2+, adenosine 5'-triphosphate and thrombin. We implemented an electromechanical biosensor for the detection of SARS-CoV-2 into an integrated and portable prototype device, and show that it detected SARS-CoV-2 RNA in less than four minutes in all nasopharyngeal samples from 33 patients with COVID-19 (with cycle threshold values of 24.9-41.3) and in none of the 54 COVID-19-negative controls, without the need for RNA extraction or nucleic acid amplification.


Subject(s)
COVID-19 , Graphite , COVID-19/diagnosis , Humans , Ions , RNA, Viral/genetics , SARS-CoV-2/genetics
11.
Chem Commun (Camb) ; 58(11): 1804-1807, 2022 Feb 03.
Article in English | MEDLINE | ID: covidwho-1639537

ABSTRACT

We present the finding of a dimeric ACE2 peptide mimetic designed through side chain cross-linking and covalent dimerization. It has a binding affinity of 16 nM for the SARS-CoV-2 spike RBD, and effectively inhibits the SARS-CoV-2 pseudovirus in Huh7-hACE2 cells with an IC50 of 190 nM and neutralizes the authentic SARS-CoV-2 in Caco2 cells with an IC50 of 2.4 µM. Our study should provide a new insight for the optimization of peptide-based anti-SARS-CoV-2 inhibitors.


Subject(s)
Antiviral Agents/pharmacology , Peptide Fragments/pharmacology , Peptidomimetics/pharmacology , SARS-CoV-2/drug effects , Amino Acid Sequence , Angiotensin-Converting Enzyme 2/chemistry , Antiviral Agents/chemical synthesis , Antiviral Agents/metabolism , Cell Line, Tumor , Humans , Microbial Sensitivity Tests , Peptide Fragments/chemical synthesis , Peptide Fragments/metabolism , Peptidomimetics/chemical synthesis , Peptidomimetics/metabolism , Protein Binding , Protein Domains , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
12.
Cell Res ; 32(3): 269-287, 2022 03.
Article in English | MEDLINE | ID: covidwho-1634806

ABSTRACT

The emergence of SARS-CoV-2 variants and potentially other highly pathogenic sarbecoviruses in the future highlights the need for pan-sarbecovirus vaccines. Here, we discovered a new STING agonist, CF501, and found that CF501-adjuvanted RBD-Fc vaccine (CF501/RBD-Fc) elicited significantly stronger neutralizing antibody (nAb) and T cell responses than Alum- and cGAMP-adjuvanted RBD-Fc in mice. Vaccination of rabbits and rhesus macaques (nonhuman primates, NHPs) with CF501/RBD-Fc elicited exceptionally potent nAb responses against SARS-CoV-2 and its nine variants and 41 S-mutants, SARS-CoV and bat SARSr-CoVs. CF501/RBD-Fc-immunized hACE2-transgenic mice were almost completely protected against SARS-CoV-2 challenge, even 6 months after the initial immunization. NHPs immunized with a single dose of CF501/RBD-Fc produced high titers of nAbs. The immunized macaques also exhibited durable humoral and cellular immune responses and showed remarkably reduced viral load in the upper and lower airways upon SARS-CoV-2 challenge even at 108 days post the final immunization. Thus, CF501/RBD-Fc can be further developed as a novel pan-sarbecovirus vaccine to combat current and future outbreaks of sarbecovirus diseases.


Subject(s)
COVID-19 , Vaccines , Animals , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/prevention & control , COVID-19 Vaccines , Macaca mulatta , Mice , Rabbits , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , T-Lymphocytes
13.
Emerg Microbes Infect ; 11(1): 351-367, 2022 Dec.
Article in English | MEDLINE | ID: covidwho-1585238

ABSTRACT

The emergence of multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern threatens the efficacy of currently approved vaccines and authorized therapeutic monoclonal antibodies (MAbs). It is hence important to continue searching for SARS-CoV-2 broadly neutralizing MAbs and defining their epitopes. Here, we isolate 9 neutralizing mouse MAbs raised against the spike protein of a SARS-CoV-2 prototype strain and evaluate their neutralizing potency towards a panel of variants, including B.1.1.7, B.1.351, B.1.617.1, and B.1.617.2. By using a combination of biochemical, virological, and cryo-EM structural analyses, we identify three types of cross-variant neutralizing MAbs, represented by S5D2, S5G2, and S3H3, respectively, and further define their epitopes. S5D2 binds the top lateral edge of the receptor-binding motif within the receptor-binding domain (RBD) with a binding footprint centred around the loop477-489, and efficiently neutralizes all variant pseudoviruses, but the potency against B.1.617.2 was observed to decrease significantly. S5G2 targets the highly conserved RBD core region and exhibits comparable neutralization towards the variant panel. S3H3 binds a previously unreported epitope located within the evolutionarily stable SD1 region and is able to near equally neutralize all of the variants tested. Our work thus defines three distinct cross-variant neutralizing sites on the SARS-CoV-2 spike protein, providing guidance for design and development of broadly effective vaccines and MAb-based therapies.


Subject(s)
COVID-19/virology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , Epitope Mapping , Female , Humans , Mice , Mice, Inbred BALB C , Neutralization Tests , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics
14.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-296092

ABSTRACT

The recurrent outbreak of coronaviruses and variants underscores the need for broadly reactive antivirals and vaccines. Here, a novel broad-spectrum human antibody named 76E1 was isolated from a COVID-19 convalescent patient and showed broad neutralization activity against multiple α- and β-coronaviruses, including the SARS-CoV-2 variants and also exhibited the binding breath to peptides containing the epitope from γ- and δ- coronaviruses. 76E1 cross-protects mice from SARS-CoV-2 and HCoV-OC43 infection in both prophylactic and treatment models. The epitope including the fusion peptide and S2’ cleavage site recognized by 76E1 was significantly conserved among α-, β-, γ- and δ- coronaviruses. We uncovered a novel mechanism of antibody neutralization that the epitope of 76E1 was proportionally less exposed in the prefusion trimeric structure of spike protein but could be unmasked by binding to the receptor ACE2. Once the epitope exposed, 76E1 inhibited S2’ cleavage, thus blocked the membrane fusion process. Our data demonstrate a key epitope targeted by broadly-neutralizing antibodies and will guide next-generation epitope-based pan-coronavirus vaccine design.

15.
Genome Med ; 13(1): 164, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1542128

ABSTRACT

BACKGROUND: The receptor-binding domain (RBD) variants of SARS-CoV-2 could impair antibody-mediated neutralization of the virus by host immunity; thus, prospective surveillance of antibody escape mutants and understanding the evolution of RBD are urgently needed. METHODS: Using the single B cell cloning technology, we isolated and characterized 93 RBD-specific antibodies from the memory B cells of four COVID-19 convalescent individuals in the early stage of the pandemic. Then, global RBD alanine scanning with a panel of 19 selected neutralizing antibodies (NAbs), including several broadly reactive NAbs, was performed. Furthermore, we assessed the impact of single natural mutation or co-mutations of concern at key positions of RBD on the neutralization escape and ACE2 binding function by recombinant proteins and pseudoviruses. RESULTS: Thirty-three amino acid positions within four independent antigenic sites (1 to 4) of RBD were identified as valuable indicators of antigenic changes in the RBD. The comprehensive escape mutation map not only confirms the widely circulating strains carrying important immune escape RBD mutations such as K417N, E484K, and L452R, but also facilitates the discovery of new immune escape-enabling mutations such as F486L, N450K, F490S, and R346S. Of note, these escape mutations could not affect the ACE2 binding affinity of RBD, among which L452R even enhanced binding. Furthermore, we showed that RBD co-mutations K417N, E484K, and N501Y present in B.1.351 appear more resistant to NAbs and human convalescent plasma from the early stage of the pandemic, possibly due to an additive effect. Conversely, double mutations E484Q and L452R present in B.1.617.1 variant show partial antibody evasion with no evidence for an additive effect. CONCLUSIONS: Our study provides a global view of the determinants for neutralizing antibody recognition, antigenic conservation, and RBD conformation. The in-depth escape maps may have value for prospective surveillance of SARS-CoV-2 immune escape variants. Special attention should be paid to the accumulation of co-mutations at distinct major antigenic sites. Finally, the new broadly reactive NAbs described here represent new potential opportunities for the prevention and treatment of COVID-19.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 , Immune Evasion , Mutation , SARS-CoV-2 , Spike Glycoprotein, Coronavirus , Adult , Aged , B-Lymphocytes/immunology , COVID-19/genetics , COVID-19/immunology , Female , Humans , Immunologic Memory , Male , Middle Aged , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
16.
Cell Res ; 32(1): 24-37, 2022 01.
Article in English | MEDLINE | ID: covidwho-1537308

ABSTRACT

Host cellular receptors play key roles in the determination of virus tropism and pathogenesis. However, little is known about SARS-CoV-2 host receptors with the exception of ACE2. Furthermore, ACE2 alone cannot explain the multi-organ tropism of SARS-CoV-2 nor the clinical differences between SARS-CoV-2 and SARS-CoV, suggesting the involvement of other receptor(s). Here, we performed genomic receptor profiling to screen 5054 human membrane proteins individually for interaction with the SARS-CoV-2 capsid spike (S) protein. Twelve proteins, including ACE2, ASGR1, and KREMEN1, were identified with diverse S-binding affinities and patterns. ASGR1 or KREMEN1 is sufficient for the entry of SARS-CoV-2 but not SARS-CoV in vitro and in vivo. SARS-CoV-2 utilizes distinct ACE2/ASGR1/KREMEN1 (ASK) receptor combinations to enter different cell types, and the expression of ASK together displays a markedly stronger correlation with virus susceptibility than that of any individual receptor at both the cell and tissue levels. The cocktail of ASK-related neutralizing antibodies provides the most substantial blockage of SARS-CoV-2 infection in human lung organoids when compared to individual antibodies. Our study revealed an interacting host receptome of SARS-CoV-2, and identified ASGR1 and KREMEN1 as alternative functional receptors that play essential roles in ACE2-independent virus entry, providing insight into SARS-CoV-2 tropism and pathogenesis, as well as a community resource and potential therapeutic strategies for further COVID-19 investigations.


Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Asialoglycoprotein Receptor , Humans , Membrane Proteins , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Virus Internalization
17.
Bioorg Med Chem ; 53: 116523, 2022 01 01.
Article in English | MEDLINE | ID: covidwho-1525708

ABSTRACT

Since the end of 2019, the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has evolved into a global pandemic. There is an urgent need for effective and low-toxic antiviral drugs to remedy Remdesivir's limitation. Hydroxychloroquine, a broad spectrum anti-viral drug, showed inhibitory activity against SARS-CoV-2 in some studies. Thus, we adopted a drug repurposing strategy, and further investigated hydroxychloroquine. We obtained different configurations of hydroxychloroquine side chains by using chiral resolution technique, and successfully furnished R-/S-hydroxychloroquine sulfate through chemical synthesis. The R configuration of hydroxychloroquine was found to exhibit higher antiviral activity (EC50 = 3.05 µM) and lower toxicity in vivo. Therefore, R-HCQ is a promising lead compound against SARS-CoV-2. Our research provides new strategy for the subsequent research on small molecule inhibitors against SARS-CoV-2.


Subject(s)
Antiviral Agents/pharmacology , Hydroxychloroquine/pharmacology , SARS-CoV-2/drug effects , Animals , Antiviral Agents/chemical synthesis , Antiviral Agents/toxicity , Chlorocebus aethiops , Drug Repositioning , Female , Hydroxychloroquine/chemical synthesis , Hydroxychloroquine/toxicity , Male , Mice , Microbial Sensitivity Tests , Stereoisomerism , Vero Cells
18.
Nat Commun ; 12(1): 6304, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1500462

ABSTRACT

Accumulating mutations in the SARS-CoV-2 Spike (S) protein can increase the possibility of immune escape, challenging the present COVID-19 prophylaxis and clinical interventions. Here, 3 receptor binding domain (RBD) specific monoclonal antibodies (mAbs), 58G6, 510A5 and 13G9, with high neutralizing potency blocking authentic SARS-CoV-2 virus display remarkable efficacy against authentic B.1.351 virus. Surprisingly, structural analysis has revealed that 58G6 and 13G9 both recognize the steric region S470-495 on the RBD, overlapping the E484K mutation presented in B.1.351. Also, 58G6 directly binds to another region S450-458 in the RBD. Significantly, 58G6 and 510A5 both demonstrate prophylactic efficacy against authentic SARS-CoV-2 and B.1.351 viruses in the transgenic mice expressing human ACE2 (hACE2), protecting weight loss and reducing virus loads. Together, we have evidenced 2 potent neutralizing Abs with unique mechanism targeting authentic SARS-CoV-2 mutants, which can be promising candidates to fulfill the urgent needs for the prolonged COVID-19 pandemic.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/prevention & control , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/administration & dosage , Antibodies, Neutralizing/chemistry , Antibodies, Viral/administration & dosage , Antibodies, Viral/chemistry , Binding Sites , COVID-19/pathology , COVID-19/virology , Epitopes , Humans , Mice , Mice, Transgenic , Mutation , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Viral Load/drug effects , Weight Loss/drug effects
19.
Signal Transduct Target Ther ; 6(1): 378, 2021 11 03.
Article in English | MEDLINE | ID: covidwho-1500450

ABSTRACT

The current COVID-19 pandemic has heavily burdened the global public health system and may keep simmering for years. The frequent emergence of immune escape variants have spurred the search for prophylactic vaccines and therapeutic antibodies that confer broad protection against SARS-CoV-2 variants. Here we show that the bivalency of an affinity maturated fully human single-domain antibody (n3113.1-Fc) exhibits exquisite neutralizing potency against SARS-CoV-2 pseudovirus, and confers effective prophylactic and therapeutic protection against authentic SARS-CoV-2 in the host cell receptor angiotensin-converting enzyme 2 (ACE2) humanized mice. The crystal structure of n3113 in complex with the receptor-binding domain (RBD) of SARS-CoV-2, combined with the cryo-EM structures of n3113 and spike ecto-domain, reveals that n3113 binds to the side surface of up-state RBD with no competition with ACE2. The binding of n3113 to this novel epitope stabilizes spike in up-state conformations but inhibits SARS-CoV-2 S mediated membrane fusion, expanding our recognition of neutralization by antibodies against SARS-CoV-2. Binding assay and pseudovirus neutralization assay show no evasion of recently prevalent SARS-CoV-2 lineages, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), and Delta (B.1.617.2) for n3113.1-Fc with Y58L mutation, demonstrating the potential of n3113.1-Fc (Y58L) as a promising candidate for clinical development to treat COVID-19.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , COVID-19 , SARS-CoV-2/chemistry , Single-Chain Antibodies/chemistry , Angiotensin-Converting Enzyme 2/immunology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/therapeutic use , Antibodies, Viral/immunology , Antibodies, Viral/therapeutic use , Crystallography, X-Ray , Epitopes/chemistry , Epitopes/immunology , Humans , Mice , SARS-CoV-2/immunology , Single-Chain Antibodies/immunology , Single-Chain Antibodies/therapeutic use
20.
Nano Lett ; 21(22): 9450-9457, 2021 11 24.
Article in English | MEDLINE | ID: covidwho-1500414

ABSTRACT

Direct SARS-CoV-2 nucleic acid testing with fast speed and high frequency is crucial for controlling the COVID-19 pandemic. Here, direct testing of SARS-CoV-2 nucleic acid is realized by field-effect transistors (FETs) with an electro-enrichable liquid gate (LG) anchored by tetrahedral DNA nanostructures (TDNs). The applied gate bias electrostatically preconcentrates nucleic acids, while the liquid gate with TDNs provides efficient analyte recognition and signal transduction. The average diagnosis time is ∼80 s, and the limit of detection approaches 1-2 copies in 100 µL of clinical samples without nucleic acid extraction and amplification. As such, TDN-LG FETs solve the dilemma of COVID-19 testing on mass scale that diagnosis accuracy and speed undergo trade-off. In addition, TDN-LG FETs achieve unamplified 10-in-1 pooled nucleic acid testing for the first time, and the results are consistent with PCR. Thus, this technology promises on-site and wide population COVID-19 screening and ensures safe world-reopening.


Subject(s)
COVID-19 , Nanostructures , Nucleic Acids , COVID-19 Testing , DNA/genetics , Humans , Pandemics , SARS-CoV-2 , Sensitivity and Specificity
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