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1.
Structure ; 2022 Jul 12.
Article in English | MEDLINE | ID: covidwho-1937225

ABSTRACT

Immunization with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike elicits diverse antibodies, but it is unclear if any of the antibodies can neutralize broadly against other beta-coronaviruses. Here, we report antibody WS6 from a mouse immunized with mRNA encoding the SARS-CoV-2 spike. WS6 bound diverse beta-coronavirus spikes and neutralized SARS-CoV-2 variants, SARS-CoV, and related sarbecoviruses. Epitope mapping revealed WS6 to target a region in the S2 subunit, which was conserved among SARS-CoV-2, Middle East respiratory syndrome (MERS)-CoV, and hCoV-OC43. The crystal structure at 2 Å resolution of WS6 revealed recognition to center on a conserved S2 helix, which was occluded in both pre- and post-fusion spike conformations. Structural and neutralization analyses indicated WS6 to neutralize by inhibiting fusion and post-viral attachment. Comparison of WS6 with other recently identified antibodies that broadly neutralize beta-coronaviruses indicated a stem-helical supersite-centered on hydrophobic residues Phe1148, Leu1152, Tyr1155, and Phe1156-to be a promising target for vaccine design.

2.
EuropePMC; 2022.
Preprint in English | EuropePMC | ID: ppcovidwho-331567

ABSTRACT

While humoral immune responses to infection or vaccination with ancestral SARS-CoV-2 have been well-characterized, responses elicited by infection with variants are less understood. Here we characterized the repertoire, epitope specificity, and cross-reactivity of antibodies elicited by Beta and Gamma variant infection compared to ancestral virus. We developed a high-throughput approach to obtain single-cell immunoglobulin sequences and isolate monoclonal antibodies for functional assessment. Spike-, RBD- and NTD-specific antibodies elicited by Beta- or Gamma-infection exhibited a remarkably similar hierarchy of epitope immunodominance for RBD and convergent V gene usage when compared to ancestral virus infection. Additionally, similar public B cell clones were elicited regardless of infecting variant. These convergent responses may account for the broad cross-reactivity and continued efficacy of vaccines based on a single ancestral variant. One Sentence Summary WA1, Beta and Gamma variants of SARS-CoV-2 all elicit antibody responses targeting similar RBD epitopes;public and cross-reactive clones are common.

3.
Science ; 376(6591): eabn8897, 2022 04 22.
Article in English | MEDLINE | ID: covidwho-1759268

ABSTRACT

The rapid spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (Omicron) variant and its resistance to neutralization by vaccinee and convalescent sera are driving a search for monoclonal antibodies with potent neutralization. To provide insight into effective neutralization, we determined cryo-electron microscopy structures and evaluated receptor binding domain (RBD) antibodies for their ability to bind and neutralize B.1.1.529. Mutations altered 16% of the B.1.1.529 RBD surface, clustered on an RBD ridge overlapping the angiotensin-converting enzyme 2 (ACE2)-binding surface and reduced binding of most antibodies. Substantial inhibitory activity was retained by select monoclonal antibodies-including A23-58.1, B1-182.1, COV2-2196, S2E12, A19-46.1, S309, and LY-CoV1404-that accommodated these changes and neutralized B.1.1.529. We identified combinations of antibodies with synergistic neutralization. The analysis revealed structural mechanisms for maintenance of potent neutralization against emerging variants.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Monoclonal , Antibodies, Neutralizing , Antibodies, Viral , COVID-19/therapy , Cryoelectron Microscopy , Humans , Immunization, Passive , Neutralization Tests , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus
4.
EuropePMC;
Preprint in English | EuropePMC | ID: ppcovidwho-327132

ABSTRACT

Immunization with SARS-CoV-2 spike elicits diverse antibodies, but can any of these neutralize broadly? Here, we report the isolation and characterization of antibody WS6, from a mouse immunized with mRNA encoding the SARS-CoV-2 spike. WS6 bound diverse beta-coronavirus spikes and neutralized SARS-CoV-2 variants, SARS-CoV, and related sarbecoviruses. Epitope mapping revealed WS6 to target a region in the S2 subunit, which was conserved among SARS-CoV-2, MERS-CoV, and hCoV-OC43. The crystal structure at 2-angstrom resolution of WS6 with its S2 epitope revealed recognition to center on a conserved helix, which was occluded in both prefusion and post-fusion spike conformations. Structural and neutralization analyses indicated WS6 to neutralize by inhibiting fusion, post-viral attachment. Comparison of WS6 to other antibodies recently identified from convalescent donors or mice immunized with diverse spikes indicated a stem-helical supersite - centered on hydrophobic residues Phe1148, Leu1152, Tyr1155, and Phe1156 - to be a promising target for vaccine design.

5.
Science ; 373(6556)2021 Aug 13.
Article in English | MEDLINE | ID: covidwho-1559379

ABSTRACT

The emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identified four receptor binding domain-targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 23 variants, including the B.1.1.7, B.1.351, P.1, B.1.429, B.1.526, and B.1.617 VOCs. Two antibodies are ultrapotent, with subnanomolar neutralization titers [half-maximal inhibitory concentration (IC50) 0.3 to 11.1 nanograms per milliliter; IC80 1.5 to 34.5 nanograms per milliliter). We define the structural and functional determinants of binding for all four VOC-targeting antibodies and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting their potential in mitigating resistance development.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/metabolism , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Antibody Affinity , Antigen-Antibody Reactions , COVID-19/virology , Humans , Immune Evasion , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/metabolism , Mutation , Neutralization Tests , Protein Domains , Receptors, Coronavirus/antagonists & inhibitors , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
6.
Sci Transl Med ; 13(616): eabj5413, 2021 Oct 20.
Article in English | MEDLINE | ID: covidwho-1406601

ABSTRACT

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern threatens the efficacy of existing vaccines and therapeutic antibodies and underscores the need for additional antibody-based tools that potently neutralize variants by targeting multiple sites of the spike protein. We isolated 216 monoclonal antibodies targeting SARS-CoV-2 from plasmablasts and memory B cells collected from patients with coronavirus disease 2019. The three most potent antibodies targeted distinct regions of the receptor binding domain (RBD), and all three neutralized the SARS-CoV-2 Alpha and Beta variants. The crystal structure of the most potent antibody, CV503, revealed that it binds to the ridge region of SARS-CoV-2 RBD, competes with the angiotensin-converting enzyme 2 receptor, and has limited contact with key variant residues K417, E484, and N501. We designed bispecific antibodies by combining nonoverlapping specificities and identified five bispecific antibodies that inhibit SARS-CoV-2 infection at concentrations of less than 1 ng/ml. Through a distinct mode of action, three bispecific antibodies cross-linked adjacent spike proteins using dual N-terminal domain­RBD specificities. One bispecific antibody was greater than 100-fold more potent than a cocktail of its parent monoclonals in vitro and prevented clinical disease in a hamster model at a dose of 2.5 mg/kg. Two bispecific antibodies in our panel comparably neutralized the Alpha, Beta, Gamma, and Delta variants and wild-type virus. Furthermore, a bispecific antibody that neutralized the Beta variant protected hamsters against SARS-CoV-2 expressing the E484K mutation. Thus, bispecific antibodies represent a promising next-generation countermeasure against SARS-CoV-2 variants of concern.


Subject(s)
Antibodies, Bispecific , Spike Glycoprotein, Coronavirus/immunology , Antibodies, Bispecific/immunology , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19 , Humans , SARS-CoV-2
7.
Science ; 373(6556)2021 Aug 13.
Article in English | MEDLINE | ID: covidwho-1295159

ABSTRACT

The emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) that are resistant to therapeutic antibodies highlights the need for continuing discovery of broadly reactive antibodies. We identified four receptor binding domain-targeting antibodies from three early-outbreak convalescent donors with potent neutralizing activity against 23 variants, including the B.1.1.7, B.1.351, P.1, B.1.429, B.1.526, and B.1.617 VOCs. Two antibodies are ultrapotent, with subnanomolar neutralization titers [half-maximal inhibitory concentration (IC50) 0.3 to 11.1 nanograms per milliliter; IC80 1.5 to 34.5 nanograms per milliliter). We define the structural and functional determinants of binding for all four VOC-targeting antibodies and show that combinations of two antibodies decrease the in vitro generation of escape mutants, suggesting their potential in mitigating resistance development.


Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , COVID-19/immunology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Spike Glycoprotein, Coronavirus/immunology , Angiotensin-Converting Enzyme 2/antagonists & inhibitors , Angiotensin-Converting Enzyme 2/metabolism , Antibodies, Neutralizing/chemistry , Antibodies, Neutralizing/metabolism , Antibodies, Viral/chemistry , Antibodies, Viral/metabolism , Antibody Affinity , Antigen-Antibody Reactions , COVID-19/virology , Humans , Immune Evasion , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/metabolism , Mutation , Neutralization Tests , Protein Domains , Receptors, Coronavirus/antagonists & inhibitors , Receptors, Coronavirus/metabolism , SARS-CoV-2/genetics , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/metabolism
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