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1.
Sci Transl Med ; : eabn1252, 2022 Apr 12.
Article in English | MEDLINE | ID: covidwho-1784766

ABSTRACT

New variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continue to arise and prolong the coronavirus disease 2019 (COVID-19) pandemic. Here we used a cell-free expression workflow to rapidly screen and optimize constructs containing multiple computationally designed miniprotein inhibitors of SARS-CoV-2. We found the broadest efficacy with a homo-trimeric version of the 75-residue angiotensin converting enzyme 2 (ACE2) mimic AHB2 (TRI2-2) designed to geometrically match the trimeric spike architecture. In the cryo-electron microscopy structure, TRI2 formed a tripod on top of the spike protein which engaged all three receptor binding domains (RBDs) simultaneously as in the design model. TRI2-2 neutralized Omicron (B.1.1.529), Delta (B.1.617.2), and all other variants tested with greater potency than that of monoclonal antibodies used clinically for the treatment of COVID-19. TRI2-2 also conferred prophylactic and therapeutic protection against SARS-CoV-2 challenge when administered intranasally in mice. Designed miniprotein receptor mimics geometrically arrayed to match pathogen receptor binding sites could be a widely applicable antiviral therapeutic strategy with advantages over antibodies and native receptor traps. By comparison, the designed proteins have resistance to viral escape and antigenic drift by construction, precisely tuned avidity, and greatly reduced chance of autoimmune responses.

2.
Science ; 375(6579): 449-454, 2022 Jan 28.
Article in English | MEDLINE | ID: covidwho-1723472

ABSTRACT

Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures against SARS-CoV-2 variants and future zoonotic sarbecoviruses. We describe the isolation and characterization of a human monoclonal antibody, designated S2K146, that broadly neutralizes viruses belonging to SARS-CoV- and SARS-CoV-2-related sarbecovirus clades which use ACE2 as an entry receptor. Structural and functional studies show that most of the virus residues that directly bind S2K146 are also involved in binding to ACE2. This allows the antibody to potently inhibit receptor attachment. S2K146 protects against SARS-CoV-2 Beta challenge in hamsters and viral passaging experiments reveal a high barrier for emergence of escape mutants, making it a good candidate for clinical development. The conserved ACE2-binding residues present a site of vulnerability that might be leveraged for developing vaccines eliciting broad sarbecovirus immunity.


Subject(s)
Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Viral/immunology , Betacoronavirus/immunology , Broadly Neutralizing Antibodies/immunology , COVID-19/therapy , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/chemistry , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/metabolism , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Antibody Affinity , Broadly Neutralizing Antibodies/chemistry , Broadly Neutralizing Antibodies/metabolism , Broadly Neutralizing Antibodies/therapeutic use , COVID-19/immunology , Cross Reactions , Cryoelectron Microscopy , Epitopes , Humans , Immune Evasion , Mesocricetus , Models, Molecular , Molecular Mimicry , Mutation , Protein Conformation , Protein Domains , Receptors, Coronavirus/chemistry , Receptors, Coronavirus/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
3.
Nature ; 604(7904): 141-145, 2022 Apr.
Article in English | MEDLINE | ID: covidwho-1684082

ABSTRACT

Germinal centres (GC) are lymphoid structures in which B cells acquire affinity-enhancing somatic hypermutations (SHM), with surviving clones differentiating into memory B cells (MBCs) and long-lived bone marrow plasma cells1-5 (BMPCs). SARS-CoV-2 mRNA vaccination induces a persistent GC response that lasts for at least six months in humans6-8. The fate of responding GC B cells as well as the functional consequences of such persistence remain unknown. Here, we detected SARS-CoV-2 spike protein-specific MBCs in 42 individuals who had received two doses of the SARS-CoV-2 mRNA vaccine BNT162b2 six month earlier. Spike-specific IgG-secreting BMPCs were detected in 9 out of 11 participants. Using a combined approach of sequencing the B cell receptors of responding blood plasmablasts and MBCs, lymph node GC B cells and plasma cells and BMPCs from eight individuals and expression of the corresponding monoclonal antibodies, we tracked the evolution of 1,540 spike-specific B cell clones. On average, early blood spike-specific plasmablasts exhibited the lowest SHM frequencies. By contrast, SHM frequencies of spike-specific GC B cells increased by 3.5-fold within six months after vaccination. Spike-specific MBCs and BMPCs accumulated high levels of SHM, which corresponded with enhanced anti-spike antibody avidity in blood and enhanced affinity as well as neutralization capacity of BMPC-derived monoclonal antibodies. We report how the notable persistence of the GC reaction induced by SARS-CoV-2 mRNA vaccination in humans culminates in affinity-matured long-term antibody responses that potently neutralize the virus.


Subject(s)
COVID-19 Vaccines , COVID-19 , Antibodies, Monoclonal , Antibodies, Viral , COVID-19/prevention & control , Germinal Center , Humans , RNA, Messenger/genetics , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus , Vaccination , Vaccines, Synthetic
4.
mBio ; : e0344221, 2022 Jan 25.
Article in English | MEDLINE | ID: covidwho-1649813

ABSTRACT

Recent studies have shown a temporal increase in the neutralizing antibody potency and breadth to SARS-CoV-2 variants in coronavirus disease 2019 (COVID-19) convalescent individuals. Here, we examined longitudinal antibody responses and viral neutralizing capacity to the B.1 lineage virus (Wuhan related), to variants of concern (VOC; Alpha, Beta, Gamma, and Delta), and to a local variant of interest (VOI; Lambda) in volunteers receiving the Sputnik V vaccine in Argentina. Longitudinal serum samples (N = 536) collected from 118 volunteers obtained between January and October 2021 were used. The analysis indicates that while anti-spike IgG levels significantly wane over time, the neutralizing capacity for the Wuhan-related lineages of SARS-CoV-2 and VOC is maintained within 6 months of vaccination. In addition, an improved antibody cross-neutralizing ability for circulating variants of concern (Beta and Gamma) was observed over time postvaccination. The viral variants that displayed higher escape to neutralizing antibodies with respect to the original virus (Beta and Gamma variants) were the ones showing the largest increase in susceptibility to neutralization over time after vaccination. Our observations indicate that serum neutralizing antibodies are maintained for at least 6 months and show a reduction of VOC escape to neutralizing antibodies over time after vaccination. IMPORTANCE Vaccines have been produced in record time for SARS-CoV-2, offering the possibility of halting the global pandemic. However, inequalities in vaccine accessibility in different regions of the world create a need to increase international cooperation. Sputnik V is a recombinant adenovirus-based vaccine that has been widely used in Argentina and other developing countries, but limited information is available about its elicited immune responses. Here, we examined longitudinal antibody levels and viral neutralizing capacity elicited by Sputnik V vaccination. Using a cohort of 118 volunteers, we found that while anti-spike antibodies wane over time, the neutralizing capacity to viral variants of concern and local variants of interest is maintained within 4 months of vaccination. In addition, we observed an increased cross-neutralization activity over time for the Beta and Gamma variants. This study provides valuable information about the immune response generated by a vaccine platform used in many parts of the world.

5.
mBio ; : e0337721, 2022 Jan 18.
Article in English | MEDLINE | ID: covidwho-1637923

ABSTRACT

Pathogenic coronaviruses are a major threat to global public health. Here, using a recombinant reporter virus-based compound screening approach, we identified small-molecule inhibitors that potently block the replication of severe acute respiratory syndrome virus 2 (SARS-CoV-2). Among them, JIB-04 inhibited SARS-CoV-2 replication in Vero E6 cells with a 50% effective concentration of 695 nM, with a specificity index of greater than 1,000. JIB-04 showed in vitro antiviral activity in multiple cell types, including primary human bronchial epithelial cells, against several DNA and RNA viruses, including porcine coronavirus transmissible gastroenteritis virus. In an in vivo porcine model of coronavirus infection, administration of JIB-04 reduced virus infection and associated tissue pathology, which resulted in improved weight gain and survival. These results highlight the potential utility of JIB-04 as an antiviral agent against SARS-CoV-2 and other viral pathogens. IMPORTANCE The coronavirus disease 2019 (COVID-19), the disease caused by SARS-CoV-2 infection, is an ongoing public health disaster worldwide. Although several vaccines are available as a preventive measure and the FDA approval of an orally bioavailable drug is on the horizon, there remains a need for developing antivirals against SARS-CoV-2 that could work on the early course of infection. By using infectious reporter viruses, we screened small-molecule inhibitors for antiviral activity against SARS-CoV-2. Among the top hits was JIB-04, a compound previously studied for its anticancer activity. Here, we showed that JIB-04 inhibits the replication of SARS-CoV-2 as well as different DNA and RNA viruses. Furthermore, JIB-04 conferred protection in a porcine model of coronavirus infection, although to a lesser extent when given as therapeutic rather than prophylactic doses. Our findings indicate a limited but still promising utility of JIB-04 as an antiviral agent in the combat against COVID-19 and potentially other viral diseases.

6.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294825

ABSTRACT

ABSTRACT Recent studies have shown a temporal increase in the neutralizing antibody potency and breadth to SARS-CoV-2 variants in coronavirus disease 2019 (COVID-19) convalescent individuals. Here, we examined longitudinal antibody responses and viral neutralizing capacity to the B.1 lineage virus (Wuhan related), to variants of concern (VOCs: Alpha, Beta, Gamma, and Delta) and a local variant of interest (VOI: Lambda) in volunteers receiving the Sputnik V vaccine in Argentina. A collection of 472 serum samples obtained between January and September 2021 was used. The analysis indicates that while anti-spike IgG levels significantly wane over time, the neutralizing capacity to the first-wave linages of SARS-CoV-2 and VOC are maintained within four months of vaccination. In addition, an improved antibody cross-neutralizing ability to circulating variants of concern (Beta, Gamma and Delta) was observed over time of vaccination. The viral variants that displayed higher escape to neutralizing antibodies with respect to the original virus (Beta and Gamma variants) were the ones showing the largest increase in susceptibility to neutralization over time after vaccination. Our observations indicate that serum neutralizing antibodies are maintained for at least four month and show a reduction of VOC escape over time of vaccination.

7.
Ann Intern Med ; 174(11): 1572-1585, 2021 11.
Article in English | MEDLINE | ID: covidwho-1547666

ABSTRACT

BACKGROUND: Patients with chronic inflammatory disease (CID) treated with immunosuppressive medications have increased risk for severe COVID-19. Although mRNA-based SARS-CoV-2 vaccination provides protection in immunocompetent persons, immunogenicity in immunosuppressed patients with CID is unclear. OBJECTIVE: To determine the immunogenicity of mRNA-based SARS-CoV-2 vaccines in patients with CID. DESIGN: Prospective observational cohort study. SETTING: Two U.S. CID referral centers. PARTICIPANTS: Volunteer sample of adults with confirmed CID eligible for early COVID-19 vaccination, including hospital employees of any age and patients older than 65 years. Immunocompetent participants were recruited separately from hospital employees. All participants received 2 doses of mRNA vaccine against SARS-CoV-2 between 10 December 2020 and 20 March 2021. Participants were assessed within 2 weeks before vaccination and 20 days after final vaccination. MEASUREMENTS: Anti-SARS-CoV-2 spike (S) IgG+ binding in all participants, and neutralizing antibody titers and circulating S-specific plasmablasts in a subset to assess humoral response after vaccination. RESULTS: Most of the 133 participants with CID (88.7%) and all 53 immunocompetent participants developed antibodies in response to mRNA-based SARS-CoV-2 vaccination, although some with CID developed numerically lower titers of anti-S IgG. Anti-S IgG antibody titers after vaccination were lower in participants with CID receiving glucocorticoids (n = 17) than in those not receiving them; the geometric mean of anti-S IgG antibodies was 357 (95% CI, 96 to 1324) for participants receiving prednisone versus 2190 (CI, 1598 to 3002) for those not receiving it. Anti-S IgG antibody titers were also lower in those receiving B-cell depletion therapy (BCDT) (n = 10). Measures of immunogenicity differed numerically between those who were and those who were not receiving antimetabolites (n = 48), tumor necrosis factor inhibitors (n = 39), and Janus kinase inhibitors (n = 11); however, 95% CIs were wide and overlapped. Neutralization titers seemed generally consistent with anti-S IgG results. Results were not adjusted for differences in baseline clinical factors, including other immunosuppressant therapies. LIMITATIONS: Small sample that lacked demographic diversity, and residual confounding. CONCLUSION: Compared with nonusers, patients with CID treated with glucocorticoids and BCDT seem to have lower SARS-CoV-2 vaccine-induced antibody responses. These preliminary findings require confirmation in a larger study. PRIMARY FUNDING SOURCE: The Leona M. and Harry B. Helmsley Charitable Trust, Marcus Program in Precision Medicine Innovation, National Center for Advancing Translational Sciences, and National Institute of Arthritis and Musculoskeletal and Skin Diseases.

8.
Cell Rep ; 37(4): 109881, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1458602

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has necessitated the rapid development of antibody-based therapies and vaccines as countermeasures. Here, we use cryoelectron microscopy (cryo-EM) to characterize two protective anti-SARS-CoV-2 murine monoclonal antibodies (mAbs) in complex with the spike protein, revealing similarities between epitopes targeted by human and murine B cells. The more neutralizing mAb, 2B04, binds the receptor-binding motif (RBM) of the receptor-binding domain (RBD) and competes with angiotensin-converting enzyme 2 (ACE2). By contrast, 2H04 binds adjacent to the RBM and does not compete for ACE2 binding. Naturally occurring sequence variants of SARS-CoV-2 and corresponding neutralization escape variants selected in vitro map to our structurally defined epitopes, suggesting that SARS-CoV-2 might evade therapeutic antibodies with a limited set of mutations, underscoring the importance of combination mAb therapeutics. Finally, we show that 2B04 neutralizes SARS-CoV-2 infection by preventing ACE2 engagement, whereas 2H04 reduces host cell attachment without directly disrupting ACE2-RBM interactions, providing distinct inhibitory mechanisms used by RBD-specific mAbs.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/metabolism , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/chemistry , Antibodies, Viral/chemistry , Cryoelectron Microscopy , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/immunology , Humans , Mice , Protein Interaction Domains and Motifs/immunology , Protein Structure, Quaternary , Spike Glycoprotein, Coronavirus/chemistry
9.
Immunity ; 54(9): 2159-2166.e6, 2021 09 14.
Article in English | MEDLINE | ID: covidwho-1454205

ABSTRACT

The emergence of SARS-CoV-2 antigenic variants with increased transmissibility is a public health threat. Some variants show substantial resistance to neutralization by SARS-CoV-2 infection- or vaccination-induced antibodies. Here, we analyzed receptor binding domain-binding monoclonal antibodies derived from SARS-CoV-2 mRNA vaccine-elicited germinal center B cells for neutralizing activity against the WA1/2020 D614G SARS-CoV-2 strain and variants of concern. Of five monoclonal antibodies that potently neutralized the WA1/2020 D614G strain, all retained neutralizing capacity against the B.1.617.2 variant, four also neutralized the B.1.1.7 variant, and only one, 2C08, also neutralized the B.1.351 and B.1.1.28 variants. 2C08 reduced lung viral load and morbidity in hamsters challenged with the WA1/2020 D614G, B.1.351, or B.1.617.2 strains. Clonal analysis identified 2C08-like public clonotypes among B cells responding to SARS-CoV-2 infection or vaccination in 41 out of 181 individuals. Thus, 2C08-like antibodies can be induced by SARS-CoV-2 vaccines and mitigate resistance by circulating variants of concern.


Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , B-Lymphocytes/immunology , COVID-19 Vaccines/immunology , COVID-19/immunology , Germinal Center/immunology , Lung/virology , SARS-CoV-2/physiology , Animals , Cells, Cultured , Clone Cells , Cricetinae , Disease Models, Animal , Humans , Neutralization Tests , Spike Glycoprotein, Coronavirus/immunology , Vaccination , Viral Load
10.
mBio ; 12(5): e0239521, 2021 10 26.
Article in English | MEDLINE | ID: covidwho-1406605

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein is the main target for neutralizing antibodies. These antibodies can be elicited through immunization or passively transferred as therapeutics in the form of convalescent-phase sera or monoclonal antibodies (MAbs). Potently neutralizing antibodies are expected to confer protection; however, it is unclear whether weakly neutralizing antibodies contribute to protection. Also, their mechanism of action in vivo is incompletely understood. Here, we demonstrate that 2B04, an antibody with an ultrapotent neutralizing activity (50% inhibitory concentration [IC50] of 0.04 µg/ml), protects hamsters against SARS-CoV-2 in a prophylactic and therapeutic infection model. Protection is associated with reduced weight loss and viral loads in nasal turbinates and lungs after challenge. MAb 2B04 also blocked aerosol transmission of the virus to naive contacts. We next examined three additional MAbs (2C02, 2C03, and 2E06), recognizing distinct epitopes within the receptor binding domain of spike protein that possess either minimal (2C02 and 2E06, IC50 > 20 µg/ml) or weak (2C03, IC50 of 5 µg/ml) virus neutralization capacity in vitro. Only 2C03 protected Syrian hamsters from weight loss and reduced lung viral load after SARS-CoV-2 infection. Finally, we demonstrated that Fc-Fc receptor interactions were not required for protection when 2B04 and 2C03 were administered prophylactically. These findings inform the mechanism of protection and support the rational development of antibody-mediated protection against SARS-CoV-2 infections. IMPORTANCE The ongoing coronavirus disease 2019 (COVID-19) pandemic, caused by SARS-CoV-2, has resulted in the loss of millions of lives. Safe and effective vaccines are considered the ultimate remedy for the global social and economic disruption caused by the pandemic. However, a thorough understanding of the immune correlates of protection against this virus is lacking. Here, we characterized four different monoclonal antibodies and evaluated their ability to prevent or treat SARS-CoV-2 infection in Syrian hamsters. These antibodies varied in their ability to neutralize the virus in vitro. Prophylactic administration of potent and weakly neutralizing antibodies protected against SARS-CoV-2 infection, and this effect was Fc receptor independent. The potent neutralizing antibody also had therapeutic efficacy and eliminated onward aerosol transmission. In contrast, minimally neutralizing antibodies provided no protection against infection with SARS-CoV-2 in Syrian hamsters. Combined, these studies highlight the significance of weakly neutralizing antibodies in the protection against SARS-CoV-2 infection and associated disease.


Subject(s)
Antibodies, Monoclonal/metabolism , Antibodies, Neutralizing/metabolism , COVID-19/metabolism , Receptors, Fc/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Animals , COVID-19/prevention & control , Cricetinae , Male , Mesocricetus , Protein Binding
11.
Cell Host Microbe ; 29(1): 44-57.e9, 2021 01 13.
Article in English | MEDLINE | ID: covidwho-1385265

ABSTRACT

Antibodies targeting the SARS-CoV-2 spike receptor-binding domain (RBD) are being developed as therapeutics and are a major contributor to neutralizing antibody responses elicited by infection. Here, we describe a deep mutational scanning method to map how all amino-acid mutations in the RBD affect antibody binding and apply this method to 10 human monoclonal antibodies. The escape mutations cluster on several surfaces of the RBD that broadly correspond to structurally defined antibody epitopes. However, even antibodies targeting the same surface often have distinct escape mutations. The complete escape maps predict which mutations are selected during viral growth in the presence of single antibodies. They further enable the design of escape-resistant antibody cocktails-including cocktails of antibodies that compete for binding to the same RBD surface but have different escape mutations. Therefore, complete escape-mutation maps enable rational design of antibody therapeutics and assessment of the antigenic consequences of viral evolution.


Subject(s)
SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology , Spike Glycoprotein, Coronavirus/metabolism , Angiotensin-Converting Enzyme 2/chemistry , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Binding Sites , Epitopes/immunology , Gene Library , High-Throughput Nucleotide Sequencing , Humans , Protein Domains , SARS-CoV-2/genetics , Saccharomyces cerevisiae/genetics , Spike Glycoprotein, Coronavirus/chemistry
12.
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
13.
Nature ; 597(7874): 103-108, 2021 09.
Article in English | MEDLINE | ID: covidwho-1316713

ABSTRACT

The recent emergence of SARS-CoV-2 variants of concern1-10 and the recurrent spillovers of coronaviruses11,12 into the human population highlight the need for broadly neutralizing antibodies that are not affected by the ongoing antigenic drift and that can prevent or treat future zoonotic infections. Here we describe a human monoclonal antibody designated S2X259, which recognizes a highly conserved cryptic epitope of the receptor-binding domain and cross-reacts with spikes from all clades of sarbecovirus. S2X259 broadly neutralizes spike-mediated cell entry of SARS-CoV-2, including variants of concern (B.1.1.7, B.1.351, P.1, and B.1.427/B.1.429), as well as a wide spectrum of human and potentially zoonotic sarbecoviruses through inhibition of angiotensin-converting enzyme 2 (ACE2) binding to the receptor-binding domain. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses an escape profile that is limited to a single substitution, G504D. We show that prophylactic and therapeutic administration of S2X259 protects Syrian hamsters (Mesocricetus auratus) against challenge with the prototypic SARS-CoV-2 and the B.1.351 variant of concern, which suggests that this monoclonal antibody is a promising candidate for the prevention and treatment of emergent variants and zoonotic infections. Our data reveal a key antigenic site that is targeted by broadly neutralizing antibodies and will guide the design of vaccines that are effective against all sarbecoviruses.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/therapeutic use , Antibodies, Viral/immunology , Broadly Neutralizing Antibodies/immunology , Broadly Neutralizing Antibodies/therapeutic use , COVID-19/prevention & control , SARS-CoV-2/classification , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Viral/chemistry , Antibodies, Viral/therapeutic use , Broadly Neutralizing Antibodies/chemistry , COVID-19/immunology , COVID-19/virology , Cross Reactions/immunology , Disease Models, Animal , Female , Humans , Immune Evasion/genetics , Immune Evasion/immunology , Mesocricetus/immunology , Mesocricetus/virology , Mutation , Neutralization Tests , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Viral Zoonoses/immunology , Viral Zoonoses/prevention & control , Viral Zoonoses/virology
14.
Nature ; 597(7874): 97-102, 2021 09.
Article in English | MEDLINE | ID: covidwho-1309448

ABSTRACT

An ideal therapeutic anti-SARS-CoV-2 antibody would resist viral escape1-3, have activity against diverse sarbecoviruses4-7, and be highly protective through viral neutralization8-11 and effector functions12,13. Understanding how these properties relate to each other and vary across epitopes would aid the development of therapeutic antibodies and guide vaccine design. Here we comprehensively characterize escape, breadth and potency across a panel of SARS-CoV-2 antibodies targeting the receptor-binding domain (RBD). Despite a trade-off between in vitro neutralization potency and breadth of sarbecovirus binding, we identify neutralizing antibodies with exceptional sarbecovirus breadth and a corresponding resistance to SARS-CoV-2 escape. One of these antibodies, S2H97, binds with high affinity across all sarbecovirus clades to a cryptic epitope and prophylactically protects hamsters from viral challenge. Antibodies that target the angiotensin-converting enzyme 2 (ACE2) receptor-binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency. Nevertheless, we also characterize a potent RBM antibody (S2E128) with breadth across sarbecoviruses related to SARS-CoV-2 and a high barrier to viral escape. These data highlight principles underlying variation in escape, breadth and potency among antibodies that target the RBD, and identify epitopes and features to prioritize for therapeutic development against the current and potential future pandemics.


Subject(s)
Broadly Neutralizing Antibodies/immunology , COVID-19/virology , Cross Reactions/immunology , Immune Evasion , SARS-CoV-2/classification , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Viral/chemistry , Antibodies, Viral/immunology , Antibody Affinity , Broadly Neutralizing Antibodies/chemistry , COVID-19/drug therapy , COVID-19/immunology , COVID-19 Vaccines/chemistry , COVID-19 Vaccines/immunology , Cell Line , Cricetinae , Epitopes, B-Lymphocyte/chemistry , Epitopes, B-Lymphocyte/genetics , Epitopes, B-Lymphocyte/immunology , Female , Humans , Immune Evasion/genetics , Immune Evasion/immunology , Male , Mesocricetus , Middle Aged , Models, Molecular , SARS-CoV-2/chemistry , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Vaccinology
15.
Hum Vaccin Immunother ; : 1-10, 2021 Jul 06.
Article in English | MEDLINE | ID: covidwho-1297358

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with amino-acid substitutions and deletions in spike protein (S) can reduce the effectiveness of monoclonal antibodies (mAbs) and may compromise immunity induced by vaccines. We report a polyclonal, fully human, anti-SARS-CoV-2 immunoglobulin produced in transchromosomic bovines (Tc-hIgG-SARS-CoV-2) hyperimmunized with two doses of plasmid DNA encoding the SARS-CoV-2 Wuhan strain S gene, followed by repeated immunization with S protein purified from insect cells. The resulting Tc-hIgG-SARS-CoV-2, termed SAB-185, efficiently neutralizes SARS-CoV-2, and vesicular stomatitis virus (VSV) SARS-CoV-2 chimeras in vitro. Neutralization potency was retained for S variants including S477N, E484K, and N501Y, substitutions present in recent variants of concern. In contrast to the ease of selection of escape variants with mAbs and convalescent human plasma, we were unable to isolate VSV-SARS-CoV-2 mutants resistant to Tc-hIgG-SARS-CoV-2 neutralization. This fully human immunoglobulin that potently inhibits SARS-CoV-2 infection may provide an effective therapeutic to combat COVID-19.

16.
Cell Rep ; 36(2): 109364, 2021 07 13.
Article in English | MEDLINE | ID: covidwho-1283971

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) variants govern transmissibility, responsiveness to vaccination, and disease severity. In a screen for new models of SARS-CoV-2 infection, we identify human H522 lung adenocarcinoma cells as naturally permissive to SARS-CoV-2 infection despite complete absence of angiotensin-converting enzyme 2 (ACE2) expression. Remarkably, H522 infection requires the E484D S variant; viruses expressing wild-type S are not infectious. Anti-S monoclonal antibodies differentially neutralize SARS-CoV-2 E484D S in H522 cells as compared to ACE2-expressing cells. Sera from vaccinated individuals block this alternative entry mechanism, whereas convalescent sera are less effective. Although the H522 receptor remains unknown, depletion of surface heparan sulfates block H522 infection. Temporally resolved transcriptomic and proteomic profiling reveal alterations in cell cycle and the antiviral host cell response, including MDA5-dependent activation of type I interferon signaling. These findings establish an alternative SARS-CoV-2 host cell receptor for the E484D SARS-CoV-2 variant, which may impact tropism of SARS-CoV-2 and consequently human disease pathogenesis.


Subject(s)
COVID-19/immunology , COVID-19/metabolism , Receptors, Virus , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Substitution , Angiotensin-Converting Enzyme 2 , Animals , Antibodies, Monoclonal/immunology , Antibodies, Viral/immunology , Cell Cycle , Cell Line, Tumor , Chlorocebus aethiops , Gene Expression Profiling , Heparitin Sulfate/metabolism , Humans , Interferon Type I/metabolism , Interferon-Induced Helicase, IFIH1/metabolism , Models, Biological , Protein Binding , Protein Domains , Proteomics , Receptors, Virus/metabolism , SARS-CoV-2 , Serine Endopeptidases/metabolism , Signal Transduction , Spike Glycoprotein, Coronavirus/genetics , Vero Cells , Virus Internalization , Virus Replication
17.
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
18.
Res Sq ; 2021 Apr 23.
Article in English | MEDLINE | ID: covidwho-1237037

ABSTRACT

Rapidly-emerging variants jeopardize antibody-based countermeasures against SARS-CoV-2. While recent cell culture experiments have demonstrated loss of potency of several anti-spike neutralizing antibodies against SARS-CoV-2 variant strains1-3, the in vivo significance of these results remains uncertain. Here, using a panel of monoclonal antibodies (mAbs) corresponding to many in advanced clinical development by Vir Biotechnology, AbbVie, AstraZeneca, Regeneron, and Lilly we report the impact on protection in animals against authentic SARS-CoV-2 variants including WA1/2020 strains, a B.1.1.7 isolate, and chimeric strains with South African (B.1.351) or Brazilian (B.1.1.28) spike genes. Although some individual mAbs showed reduced or abrogated neutralizing activity against B.1.351 and B.1.1.28 viruses with E484K spike protein mutations in cell culture, low prophylactic doses of mAb combinations protected against infection in K18-hACE2 transgenic mice, 129S2 immunocompetent mice, and hamsters without emergence of resistance. Two exceptions were mAb LY-CoV555 monotherapy which lost all protective activity in vivo, and AbbVie 2B04/47D11, which showed partial loss of activity. When administered after infection as therapy, higher doses of mAb cocktails protected in vivo against viruses displaying a B.1.351 spike gene. Thus, many, but not all, of the antibody products with Emergency Use Authorization should retain substantial efficacy against the prevailing SARS-CoV-2 variant strains.

19.
Cell ; 184(9): 2332-2347.e16, 2021 04 29.
Article in English | MEDLINE | ID: covidwho-1135276

ABSTRACT

The SARS-CoV-2 spike (S) glycoprotein contains an immunodominant receptor-binding domain (RBD) targeted by most neutralizing antibodies (Abs) in COVID-19 patient plasma. Little is known about neutralizing Abs binding to epitopes outside the RBD and their contribution to protection. Here, we describe 41 human monoclonal Abs (mAbs) derived from memory B cells, which recognize the SARS-CoV-2 S N-terminal domain (NTD) and show that a subset of them neutralize SARS-CoV-2 ultrapotently. We define an antigenic map of the SARS-CoV-2 NTD and identify a supersite (designated site i) recognized by all known NTD-specific neutralizing mAbs. These mAbs inhibit cell-to-cell fusion, activate effector functions, and protect Syrian hamsters from SARS-CoV-2 challenge, albeit selecting escape mutants in some animals. Indeed, several SARS-CoV-2 variants, including the B.1.1.7, B.1.351, and P.1 lineages, harbor frequent mutations within the NTD supersite, suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs for protective immunity and vaccine design.


Subject(s)
Antigens, Viral/immunology , SARS-CoV-2/immunology , Animals , Antibodies, Monoclonal/chemistry , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , COVID-19/immunology , COVID-19/virology , Cricetinae , Epitope Mapping , Genetic Variation , Models, Molecular , Mutation/genetics , Neutralization Tests , Protein Domains , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , SARS-CoV-2/ultrastructure
20.
Cell Host Microbe ; 29(3): 477-488.e4, 2021 03 10.
Article in English | MEDLINE | ID: covidwho-1053270

ABSTRACT

Neutralizing antibodies against the SARS-CoV-2 spike (S) protein are a goal of COVID-19 vaccines and have received emergency use authorization as therapeutics. However, viral escape mutants could compromise efficacy. To define immune-selected mutations in the S protein, we exposed a VSV-eGFP-SARS-CoV-2-S chimeric virus, in which the VSV glycoprotein is replaced with the S protein, to 19 neutralizing monoclonal antibodies (mAbs) against the receptor-binding domain (RBD) and generated 50 different escape mutants. Each mAb had a unique resistance profile, although many shared residues within an epitope of the RBD. Some variants (e.g., S477N) were resistant to neutralization by multiple mAbs, whereas others (e.g., E484K) escaped neutralization by convalescent sera. Additionally, sequential selection identified mutants that escape neutralization by antibody cocktails. Comparing these antibody-mediated mutations with sequence variation in circulating SARS-CoV-2 revealed substitutions that may attenuate neutralizing immune responses in some humans and thus warrant further investigation.


Subject(s)
Antibodies, Monoclonal/blood , Antibodies, Viral/blood , Mutation , Neutralization Tests/methods , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/genetics , Amino Acid Substitution , Angiotensin-Converting Enzyme 2/genetics , Animals , Antibodies, Monoclonal/immunology , Antibodies, Neutralizing/immunology , Antibodies, Neutralizing/pharmacology , Antibodies, Viral/immunology , COVID-19/virology , COVID-19 Vaccines/immunology , Chlorocebus aethiops , Female , Humans , Mice , Mice, Inbred BALB C , Models, Molecular , Protein Binding , Receptors, Virus/metabolism , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vero Cells
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