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1.
Cell ; 2024 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-39383863

RESUMO

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolution has resulted in viral escape from clinically authorized monoclonal antibodies (mAbs), creating a need for mAbs that are resilient to epitope diversification. Broadly neutralizing coronavirus mAbs that are sufficiently potent for clinical development and retain activity despite viral evolution remain elusive. We identified a human mAb, designated VIR-7229, which targets the viral receptor-binding motif (RBM) with unprecedented cross-reactivity to all sarbecovirus clades, including non-ACE2-utilizing bat sarbecoviruses, while potently neutralizing SARS-CoV-2 variants since 2019, including the recent EG.5, BA.2.86, and JN.1. VIR-7229 tolerates extraordinary epitope variability, partly attributed to its high binding affinity, receptor molecular mimicry, and interactions with RBM backbone atoms. Consequently, VIR-7229 features a high barrier for selection of escape mutants, which are rare and associated with reduced viral fitness, underscoring its potential to be resilient to future viral evolution. VIR-7229 is a strong candidate to become a next-generation medicine.

2.
Cell ; 184(9): 2332-2347.e16, 2021 04 29.
Artigo em Inglês | MEDLINE | ID: mdl-33761326

RESUMO

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.


Assuntos
Antígenos Virais/imunologia , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , COVID-19/virologia , Cricetinae , Mapeamento de Epitopos , Variação Genética , Modelos Moleculares , Mutação/genética , Testes de Neutralização , Domínios Proteicos , RNA Viral/genética , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/ultraestrutura
3.
Cell ; 184(21): 5432-5447.e16, 2021 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-34619077

RESUMO

Understanding vaccine-elicited protection against SARS-CoV-2 variants and other sarbecoviruses is key for guiding public health policies. We show that a clinical stage multivalent SARS-CoV-2 spike receptor-binding domain nanoparticle (RBD-NP) vaccine protects mice from SARS-CoV-2 challenge after a single immunization, indicating a potential dose-sparing strategy. We benchmarked serum neutralizing activity elicited by RBD-NPs in non-human primates against a lead prefusion-stabilized SARS-CoV-2 spike (HexaPro) using a panel of circulating mutants. Polyclonal antibodies elicited by both vaccines are similarly resilient to many RBD residue substitutions tested, although mutations at and surrounding position 484 have negative consequences for neutralization. Mosaic and cocktail nanoparticle immunogens displaying multiple sarbecovirus RBDs elicit broad neutralizing activity in mice and protect mice against SARS-CoV challenge even in the absence of SARS-CoV RBD in the vaccine. This study provides proof of principle that multivalent sarbecovirus RBD-NPs induce heterotypic protection and motivates advancing such broadly protective sarbecovirus vaccines to the clinic.

4.
Nature ; 603(7903): 913-918, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35114688

RESUMO

Two different sarbecoviruses have caused major human outbreaks in the past two decades1,2. Both of these sarbecoviruses, SARS-CoV-1 and SARS-CoV-2, engage ACE2 through the spike receptor-binding domain2-6. However, binding to ACE2 orthologues of humans, bats and other species has been observed only sporadically among the broader diversity of bat sarbecoviruses7-11. Here we use high-throughput assays12 to trace the evolutionary history of ACE2 binding across a diverse range of sarbecoviruses and ACE2 orthologues. We find that ACE2 binding is an ancestral trait of sarbecovirus receptor-binding domains that has subsequently been lost in some clades. Furthermore, we reveal that bat sarbecoviruses from outside Asia can bind to ACE2. Moreover, ACE2 binding is highly evolvable-for many sarbecovirus receptor-binding domains, there are single amino-acid mutations that enable binding to new ACE2 orthologues. However, the effects of individual mutations can differ considerably between viruses, as shown by the N501Y mutation, which enhances the human ACE2-binding affinity of several SARS-CoV-2 variants of concern12 but substantially decreases it for SARS-CoV-1. Our results point to the deep ancestral origin and evolutionary plasticity of ACE2 binding, broadening the range of sarbecoviruses that should be considered to have spillover potential.


Assuntos
Enzima de Conversão de Angiotensina 2 , Evolução Molecular , SARS-CoV-2 , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Glicoproteína da Espícula de Coronavírus , Enzima de Conversão de Angiotensina 2/química , Enzima de Conversão de Angiotensina 2/genética , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Sítios de Ligação , COVID-19/virologia , Quirópteros/virologia , Humanos , Ligação Proteica , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/classificação , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/metabolismo , SARS-CoV-2/química , SARS-CoV-2/classificação , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
5.
Nature ; 603(7902): 706-714, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35104837

RESUMO

The SARS-CoV-2 Omicron BA.1 variant emerged in 20211 and has multiple mutations in its spike protein2. Here we show that the spike protein of Omicron has a higher affinity for ACE2 compared with Delta, and a marked change in its antigenicity increases Omicron's evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralizing antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralization. Importantly, the antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared with Delta. The differences in replication were mapped to the entry efficiency of the virus on the basis of spike-pseudotyped virus assays. The defect in entry of Omicron pseudotyped virus to specific cell types effectively correlated with higher cellular RNA expression of TMPRSS2, and deletion of TMPRSS2 affected Delta entry to a greater extent than Omicron. Furthermore, drug inhibitors targeting specific entry pathways3 demonstrated that the Omicron spike inefficiently uses the cellular protease TMPRSS2, which promotes cell entry through plasma membrane fusion, with greater dependency on cell entry through the endocytic pathway. Consistent with suboptimal S1/S2 cleavage and inability to use TMPRSS2, syncytium formation by the Omicron spike was substantially impaired compared with the Delta spike. The less efficient spike cleavage of Omicron at S1/S2 is associated with a shift in cellular tropism away from TMPRSS2-expressing cells, with implications for altered pathogenesis.


Assuntos
COVID-19/patologia , COVID-19/virologia , Fusão de Membrana , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidade , Serina Endopeptidases/metabolismo , Internalização do Vírus , Adulto , Idoso , Idoso de 80 Anos ou mais , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/imunologia , Vacinas contra COVID-19/imunologia , Linhagem Celular , Membrana Celular/metabolismo , Membrana Celular/virologia , Chlorocebus aethiops , Convalescença , Feminino , Humanos , Soros Imunes/imunologia , Intestinos/patologia , Intestinos/virologia , Pulmão/patologia , Pulmão/virologia , Masculino , Pessoa de Meia-Idade , Mutação , Mucosa Nasal/patologia , Mucosa Nasal/virologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Técnicas de Cultura de Tecidos , Virulência , Replicação Viral
6.
Nature ; 602(7898): 664-670, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35016195

RESUMO

The recently emerged SARS-CoV-2 Omicron variant encodes 37 amino acid substitutions in the spike protein, 15 of which are in the receptor-binding domain (RBD), thereby raising concerns about the effectiveness of available vaccines and antibody-based therapeutics. Here we show that the Omicron RBD binds to human ACE2 with enhanced affinity, relative to the Wuhan-Hu-1 RBD, and binds to mouse ACE2. Marked reductions in neutralizing activity were observed against Omicron compared to the ancestral pseudovirus in plasma from convalescent individuals and from individuals who had been vaccinated against SARS-CoV-2, but this loss was less pronounced after a third dose of vaccine. Most monoclonal antibodies that are directed against the receptor-binding motif lost in vitro neutralizing activity against Omicron, with only 3 out of 29 monoclonal antibodies retaining unaltered potency, including the ACE2-mimicking S2K146 antibody1. Furthermore, a fraction of broadly neutralizing sarbecovirus monoclonal antibodies neutralized Omicron through recognition of antigenic sites outside the receptor-binding motif, including sotrovimab2, S2X2593 and S2H974. The magnitude of Omicron-mediated immune evasion marks a major antigenic shift in SARS-CoV-2. Broadly neutralizing monoclonal antibodies that recognize RBD epitopes that are conserved among SARS-CoV-2 variants and other sarbecoviruses may prove key to controlling the ongoing pandemic and future zoonotic spillovers.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Antivirais/imunologia , Deriva e Deslocamento Antigênicos/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Testes de Neutralização , SARS-CoV-2/imunologia , Enzima de Conversão de Angiotensina 2/metabolismo , Animais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Deriva e Deslocamento Antigênicos/genética , Vacinas contra COVID-19/imunologia , Linhagem Celular , Convalescença , Epitopos de Linfócito B/imunologia , Humanos , Evasão da Resposta Imune , Camundongos , SARS-CoV-2/química , SARS-CoV-2/classificação , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Vesiculovirus/genética
7.
Nature ; 597(7874): 103-108, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34280951

RESUMO

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.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Amplamente Neutralizantes/uso terapêutico , COVID-19/prevenção & controle , SARS-CoV-2/classificação , SARS-CoV-2/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Antivirais/química , Anticorpos Antivirais/uso terapêutico , Anticorpos Amplamente Neutralizantes/química , COVID-19/imunologia , COVID-19/virologia , Reações Cruzadas/imunologia , Modelos Animais de Doenças , Feminino , Humanos , Evasão da Resposta Imune/genética , Evasão da Resposta Imune/imunologia , Mesocricetus/imunologia , Mesocricetus/virologia , Mutação , Testes de Neutralização , SARS-CoV-2/química , SARS-CoV-2/genética , Zoonoses Virais/imunologia , Zoonoses Virais/prevenção & controle , Zoonoses Virais/virologia
8.
Nicotine Tob Res ; 23(11): 1928-1935, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34228120

RESUMO

INTRODUCTION: In response to high rates of youth tobacco use, many states and localities are considering regulations on flavored tobacco products. The purpose of this study was to assess whether flavored tobacco restrictions (FTRs) in Massachusetts curb youth tobacco use over time and whether a dose-response effect of length of policy implementation on tobacco-related outcomes exists. AIMS AND METHODS: Using a quasiexperimental design, two municipalities with a FTR (adopting municipalities) were matched to a comparison municipality without a FTR. Surveys were administered before (December 2015) and after (January and February 2018) policy implementation to high school students in these municipalities (more than 2000 surveys completed at both timepoints). At follow-up, adopting municipalities had a policy in place for 1 and 2 years, respectively. In 2019, focus groups were conducted with high school students in each municipality. RESULTS: Increases seen in current tobacco use from baseline to follow-up were significantly smaller in adopting municipalities compared to the comparison (-9.4% [-14.2%, -4.6%] and -6.3% [-10.8%, -1.8%], respectively). However, policy impact was greater in one adopting municipality despite shorter length of implementation. Focus groups indicated reasons for differential impact, including proximity to localities without FTRs. CONCLUSIONS: Restrictions implemented in adopting municipalities had positive impacts on youth tobacco awareness and use 1-2 years postimplementation. Policy impact varies depending on remaining points of access to flavored tobacco, as such policy effectiveness may increase as more localities restrict these products. IMPLICATIONS: In response to high rates of youth flavored tobacco use (including flavored vape products), federal, state, and localities have passed FTRs that reduce availability of flavored tobacco in youth-accessible stores. Previous research has found that FTRs may curb youth tobacco use in the short-term; however, the long-term effectiveness remains unknown.This is the first study to show FTRs can curb youth tobacco use and reduce youth awareness of tobacco prices and brands even 2 years after policy passage. Municipality-specific factors, including proximity to localities without FTRs, may attenuate policy impact, highlighting the importance of widespread policy adoption.


Assuntos
Nicotiana , Produtos do Tabaco , Adolescente , Aromatizantes , Humanos , Massachusetts/epidemiologia , Uso de Tabaco
9.
J Gerontol Nurs ; 45(8): 23-31, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31355896

RESUMO

Involuntary discharge of nursing home (NH) residents is a prominent reason for NH complaints in the United States, but little is known about facility-initiated involuntary discharge (FID). A literature review was conducted to improve understanding of FID. The findings distinguish between six types of FID, identify populations at risk of FID, and differentiate between legal and unlawful FID practices and processes. The findings also characterize common FID destinations; show how policy, regulatory, and financial factors impact FID; and indicate that FID outcomes are commonly detrimental to the health and well-being of NH residents. Findings highlight challenges with understanding FID, including differentiating legal from unlawful FID. Although more research about NH FID is needed, the current study indicates that FID outcomes are regularly adverse, protections against unlawful FID are needed for Medicaid beneficiaries and NH residents with dementia, and stronger enforcement of existing policies and regulations regarding NH FID-including NH bed-hold requirements-are needed. [Journal of Gerontological Nursing, 45(8), 23-31.].


Assuntos
Casas de Saúde/organização & administração , Alta do Paciente , Idoso , Idoso de 80 Anos ou mais , Demência/enfermagem , Demência/psicologia , Feminino , Humanos , Masculino , Transtornos Mentais , Estados Unidos
10.
Nat Commun ; 14(1): 1164, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36859493

RESUMO

Advances in cryo-electron microscopy (cryoEM) and deep-learning guided protein structure prediction have expedited structural studies of protein complexes. However, methods for accurately determining ligand conformations are lacking. In this manuscript, we develop EMERALD, a tool for automatically determining ligand structures guided by medium-resolution cryoEM density. We show this method is robust at predicting ligands along with surrounding side chains in maps as low as 4.5 Å local resolution. Combining this with a measure of placement confidence and running on all protein/ligand structures in the EMDB, we show that 57% of ligands replicate the deposited model, 16% confidently find alternate conformations, 22% have ambiguous density where multiple conformations might be present, and 5% are incorrectly placed. For five cases where our approach finds an alternate conformation with high confidence, high-resolution crystal structures validate our placement. EMERALD and the resulting analysis should prove critical in using cryoEM to solve protein-ligand complexes.


Assuntos
Processos Mentais , Corrida , Microscopia Crioeletrônica , Ligantes
11.
bioRxiv ; 2023 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-37745523

RESUMO

Although Rhinolophus bats harbor diverse clade 3 sarbecoviruses, the structural determinants of receptor tropism along with the antigenicity of their spike (S) glycoproteins remain uncharacterized. Here, we show that the African Rinolophus bat clade 3 sarbecovirus PRD-0038 S has a broad ACE2 usage and that RBD mutations further expand receptor promiscuity and enable human ACE2 utilization. We determined a cryoEM structure of the PRD-0038 RBD bound to R. alcyone ACE2, explaining receptor tropism and highlighting differences with SARS-CoV-1 and SARS-CoV-2. Characterization of PRD-0038 S using cryoEM and monoclonal antibody reactivity revealed its distinct antigenicity relative to SARS-CoV-2 and identified PRD-0038 cross-neutralizing antibodies for pandemic preparedness. PRD-0038 S vaccination elicited greater titers of antibodies cross-reacting with vaccine-mismatched clade 2 and clade 1a sarbecoviruses compared to SARS-CoV-2 S due to broader antigenic targeting, motivating the inclusion of clade 3 antigens in next-generation vaccines for enhanced resilience to viral evolution.

12.
Cell Host Microbe ; 31(12): 1961-1973.e11, 2023 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-37989312

RESUMO

Although Rhinolophus bats harbor diverse clade 3 sarbecoviruses, the structural determinants of receptor tropism along with the antigenicity of their spike (S) glycoproteins remain uncharacterized. Here, we show that the African Rhinolophus bat clade 3 sarbecovirus PRD-0038 S has a broad angiotensin-converting enzyme 2 (ACE2) usage and that receptor-binding domain (RBD) mutations further expand receptor promiscuity and enable human ACE2 utilization. We determine a cryo-EM structure of the PRD-0038 RBD bound to Rhinolophus alcyone ACE2, explaining receptor tropism and highlighting differences with SARS-CoV-1 and SARS-CoV-2. Characterization of PRD-0038 S using cryo-EM and monoclonal antibody reactivity reveals its distinct antigenicity relative to SARS-CoV-2 and identifies PRD-0038 cross-neutralizing antibodies for pandemic preparedness. PRD-0038 S vaccination elicits greater titers of antibodies cross-reacting with vaccine-mismatched clade 2 and clade 1a sarbecoviruses compared with SARS-CoV-2 S due to broader antigenic targeting, motivating the inclusion of clade 3 antigens in next-generation vaccines for enhanced resilience to viral evolution.


Assuntos
Quirópteros , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave , Animais , Humanos , Enzima de Conversão de Angiotensina 2 , SARS-CoV-2/genética , Tropismo , Glicoproteína da Espícula de Coronavírus , Anticorpos Antivirais
13.
Science ; 375(6583): 864-868, 2022 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-35076256

RESUMO

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant of concern evades antibody-mediated immunity that comes from vaccination or infection with earlier variants due to accumulation of numerous spike mutations. To understand the Omicron antigenic shift, we determined cryo-electron microscopy and x-ray crystal structures of the spike protein and the receptor-binding domain bound to the broadly neutralizing sarbecovirus monoclonal antibody (mAb) S309 (the parent mAb of sotrovimab) and to the human ACE2 receptor. We provide a blueprint for understanding the marked reduction of binding of other therapeutic mAbs that leads to dampened neutralizing activity. Remodeling of interactions between the Omicron receptor-binding domain and human ACE2 likely explains the enhanced affinity for the host receptor relative to the ancestral virus.


Assuntos
Enzima de Conversão de Angiotensina 2/química , Anticorpos Antivirais/química , Evasão da Resposta Imune , Receptores de Coronavírus/química , SARS-CoV-2/química , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Substituição de Aminoácidos , Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/metabolismo , Deriva e Deslocamento Antigênicos , Anticorpos Amplamente Neutralizantes/química , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Amplamente Neutralizantes/metabolismo , Microscopia Crioeletrônica , Cristalografia por Raios X , Humanos , Modelos Moleculares , Mutação , Ligação Proteica , Conformação Proteica , Domínios Proteicos/genética , Domínios e Motivos de Interação entre Proteínas/genética , Receptores de Coronavírus/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/fisiologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo
14.
Science ; 375(6579): 449-454, 2022 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-34990214

RESUMO

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.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , COVID-19/terapia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Enzima de Conversão de Angiotensina 2/química , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/química , Anticorpos Antivirais/metabolismo , Afinidade de Anticorpos , Anticorpos Amplamente Neutralizantes/química , Anticorpos Amplamente Neutralizantes/metabolismo , Anticorpos Amplamente Neutralizantes/uso terapêutico , COVID-19/imunologia , Reações Cruzadas , Microscopia Crioeletrônica , Epitopos , Humanos , Evasão da Resposta Imune , Mesocricetus , Modelos Moleculares , Mimetismo Molecular , Mutação , Conformação Proteica , Domínios Proteicos , Receptores de Coronavírus/química , Receptores de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
15.
bioRxiv ; 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34671770

RESUMO

Understanding broadly neutralizing sarbecovirus antibody responses is key to developing countermeasures effective against SARS-CoV-2 variants and future spillovers of other sarbecoviruses. Here we describe the isolation and characterization of a human monoclonal antibody, designated S2K146, broadly neutralizing viruses belonging to all three sarbecovirus clades known to utilize ACE2 as entry receptor and protecting therapeutically against SARS-CoV-2 beta challenge in hamsters. Structural and functional studies show that most of the S2K146 epitope residues are shared with the ACE2 binding site and that the antibody inhibits receptor attachment competitively. Viral passaging experiments underscore an unusually high barrier for emergence of escape mutants making it an ideal candidate for clinical development. These findings unveil a key site of vulnerability for the development of a next generation of vaccines eliciting broad sarbecovirus immunity.

16.
bioRxiv ; 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33469588

RESUMO

SARS-CoV-2 entry into host cells is orchestrated by the spike (S) glycoprotein that contains an immunodominant receptor-binding domain (RBD) targeted by the largest fraction of 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 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. SARS-CoV-2 variants, including the 501Y.V2 and B.1.1.7 lineages, harbor frequent mutations localized in the NTD supersite suggesting ongoing selective pressure and the importance of NTD-specific neutralizing mAbs to protective immunity.

17.
bioRxiv ; 2021 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-34931194

RESUMO

The recently emerged SARS-CoV-2 Omicron variant harbors 37 amino acid substitutions in the spike (S) protein, 15 of which are in the receptor-binding domain (RBD), thereby raising concerns about the effectiveness of available vaccines and antibody therapeutics. Here, we show that the Omicron RBD binds to human ACE2 with enhanced affinity relative to the Wuhan-Hu-1 RBD and acquires binding to mouse ACE2. Severe reductions of plasma neutralizing activity were observed against Omicron compared to the ancestral pseudovirus for vaccinated and convalescent individuals. Most (26 out of 29) receptor-binding motif (RBM)-directed monoclonal antibodies (mAbs) lost in vitro neutralizing activity against Omicron, with only three mAbs, including the ACE2-mimicking S2K146 mAb 1 , retaining unaltered potency. Furthermore, a fraction of broadly neutralizing sarbecovirus mAbs recognizing antigenic sites outside the RBM, including sotrovimab 2 , S2X259 3 and S2H97 4 , neutralized Omicron. The magnitude of Omicron-mediated immune evasion and the acquisition of binding to mouse ACE2 mark a major SARS-CoV-2 mutational shift. Broadly neutralizing sarbecovirus mAbs recognizing epitopes conserved among SARS-CoV-2 variants and other sarbecoviruses may prove key to controlling the ongoing pandemic and future zoonotic spillovers.

18.
bioRxiv ; 2021 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-33851169

RESUMO

The recent emergence of SARS-CoV-2 variants of concern (VOC) and the recurrent spillovers of coronaviruses in 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 (mAb), designated S2X259, recognizing a highly conserved cryptic receptor-binding domain (RBD) epitope and cross-reacting with spikes from all sarbecovirus clades. S2X259 broadly neutralizes spike-mediated entry of SARS-CoV-2 including the B.1.1.7, B.1.351, P.1 and B.1.427/B.1.429 VOC, as well as a wide spectrum of human and zoonotic sarbecoviruses through inhibition of ACE2 binding to the RBD. Furthermore, deep-mutational scanning and in vitro escape selection experiments demonstrate that S2X259 possesses a remarkably high barrier to the emergence of resistance mutants. We show that prophylactic administration of S2X259 protects Syrian hamsters against challenges with the prototypic SARS-CoV-2 and the B.1.351 variant, suggesting this mAb is a promising candidate for the prevention and treatment of emergent VOC and zoonotic infections. Our data unveil a key antigenic site targeted by broadly-neutralizing antibodies and will guide the design of pan-sarbecovirus vaccines.

19.
bioRxiv ; 2021 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-33758839

RESUMO

Understanding the ability of SARS-CoV-2 vaccine-elicited antibodies to neutralize and protect against emerging variants of concern and other sarbecoviruses is key for guiding vaccine development decisions and public health policies. We show that a clinical stage multivalent SARS-CoV-2 receptor-binding domain nanoparticle vaccine (SARS-CoV-2 RBD-NP) protects mice from SARS-CoV-2-induced disease after a single shot, indicating that the vaccine could allow dose-sparing. SARS-CoV-2 RBD-NP elicits high antibody titers in two non-human primate (NHP) models against multiple distinct RBD antigenic sites known to be recognized by neutralizing antibodies. We benchmarked NHP serum neutralizing activity elicited by RBD-NP against a lead prefusion-stabilized SARS-CoV-2 spike immunogen using a panel of single-residue spike mutants detected in clinical isolates as well as the B.1.1.7 and B.1.351 variants of concern. Polyclonal antibodies elicited by both vaccines are resilient to most RBD mutations tested, but the E484K substitution has similar negative consequences for neutralization, and exhibit modest but comparable neutralization breadth against distantly related sarbecoviruses. We demonstrate that mosaic and cocktail sarbecovirus RBD-NPs elicit broad sarbecovirus neutralizing activity, including against the SARS-CoV-2 B.1.351 variant, and protect mice against severe SARS-CoV challenge even in the absence of the SARS-CoV RBD in the vaccine. This study provides proof of principle that sarbecovirus RBD-NPs induce heterotypic protection and enables advancement of broadly protective sarbecovirus vaccines to the clinic.

20.
J Pain Symptom Manage ; 58(1): 48-55.e1, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30974235

RESUMO

CONTEXT: The Centers for Medicare & Medicaid Services Hospice Quality-Reporting Program introduced the requirement that hospices nationwide begin collecting and submitting standardized patient-level quality data on July 1, 2014. OBJECTIVES: This study examined whether this requirement has increased hospice total costs, general costs, and visiting services costs. METHODS: We conducted a cross-sectional study using data from the 2012 and 2014 Medicare hospice cost reports linked to hospice claims. We measured total costs per patient day (PPD), general costs PPD, and visiting services costs PPD for freestanding hospices. We estimated the incremental costs of operating in 2014 vs. 2012 using hierarchical random effects models and adjusting for year, wage index, care volume, case-mix, and hospice and market characteristics, stratified by hospice ownership type. RESULTS: Both for-profit and nonprofit hospices reported higher total costs PPD and general services costs PPD in 2014 than 2012. Nonprofit hospices also reported higher general costs PPD in 2014 than 2012. In adjusted models, the total costs PPD in 2014 were $10.55 higher than in 2012 for nonprofit hospices and $6.43 higher for for-profit hospices. The increase in general costs PPD and visiting services costs PPD ranged from $3.15 to $5.87 by ownership and type of costs. Both for-profit and nonprofit hospices showed lower costs PPD for all types associated with more patients and longer length of stay. CONCLUSION: Hospice costs increased after the Centers for Medicare & Medicaid Services Hospice Quality-Reporting Program quality data collection/submission requirement. Complementary studies need to understand whether increased costs brought additional benefits.


Assuntos
Custos de Cuidados de Saúde , Cuidados Paliativos na Terminalidade da Vida/economia , Hospitais para Doentes Terminais/economia , Garantia da Qualidade dos Cuidados de Saúde/economia , Estudos Transversais , Humanos , Medicare/economia , Estados Unidos
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