RESUMEN
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.
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Antígenos Virales/inmunología , SARS-CoV-2/inmunología , Animales , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , COVID-19/inmunología , COVID-19/virología , Cricetinae , Mapeo Epitopo , Variación Genética , Modelos Moleculares , Mutación/genética , Pruebas de Neutralización , Dominios Proteicos , ARN Viral/genética , SARS-CoV-2/aislamiento & purificación , SARS-CoV-2/ultraestructuraRESUMEN
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.
RESUMEN
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.
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Enzima Convertidora de Angiotensina 2 , Evolución Molecular , SARS-CoV-2 , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Glicoproteína de la Espiga del Coronavirus , Enzima Convertidora de Angiotensina 2/química , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , Sitios de Unión , COVID-19/virología , Quirópteros/virología , Humanos , Unión Proteica , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/clasificación , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/genética , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo/metabolismo , SARS-CoV-2/química , SARS-CoV-2/clasificación , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
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.
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Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Deriva y Cambio Antigénico/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , Pruebas de Neutralización , SARS-CoV-2/inmunología , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales Humanizados/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Deriva y Cambio Antigénico/genética , Vacunas contra la COVID-19/inmunología , Línea Celular , Convalecencia , Epítopos de Linfocito B/inmunología , Humanos , Evasión Inmune , Ratones , SARS-CoV-2/química , SARS-CoV-2/clasificación , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunología , Glicoproteína de la Espiga del Coronavirus/metabolismo , Vesiculovirus/genéticaRESUMEN
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.
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COVID-19/patología , COVID-19/virología , Fusión de Membrana , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidad , Serina Endopeptidasas/metabolismo , Internalización del Virus , Adulto , Anciano , Anciano de 80 o más Años , Enzima Convertidora de Angiotensina 2/metabolismo , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/inmunología , Vacunas contra la COVID-19/inmunología , Línea Celular , Membrana Celular/metabolismo , Membrana Celular/virología , Chlorocebus aethiops , Convalecencia , Femenino , Humanos , Sueros Inmunes/inmunología , Intestinos/patología , Intestinos/virología , Pulmón/patología , Pulmón/virología , Masculino , Persona de Mediana Edad , Mutación , Mucosa Nasal/patología , Mucosa Nasal/virología , SARS-CoV-2/efectos de los fármacos , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Técnicas de Cultivo de Tejidos , Virulencia , Replicación ViralRESUMEN
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.
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Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Antivirales/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , Anticuerpos ampliamente neutralizantes/uso terapéutico , COVID-19/prevención & control , SARS-CoV-2/clasificación , SARS-CoV-2/inmunología , Animales , Anticuerpos Monoclonales/química , Anticuerpos Antivirales/química , Anticuerpos Antivirales/uso terapéutico , Anticuerpos ampliamente neutralizantes/química , COVID-19/inmunología , COVID-19/virología , Reacciones Cruzadas/inmunología , Modelos Animales de Enfermedad , Femenino , Humanos , Evasión Inmune/genética , Evasión Inmune/inmunología , Mesocricetus/inmunología , Mesocricetus/virología , Mutación , Pruebas de Neutralización , SARS-CoV-2/química , SARS-CoV-2/genética , Zoonosis Virales/inmunología , Zoonosis Virales/prevención & control , Zoonosis Virales/virologíaRESUMEN
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.
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Nicotiana , Productos de Tabaco , Adolescente , Aromatizantes , Humanos , Massachusetts/epidemiología , Uso de TabacoRESUMEN
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.].
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Casas de Salud/organización & administración , Alta del Paciente , Anciano , Anciano de 80 o más Años , Demencia/enfermería , Demencia/psicología , Femenino , Humanos , Masculino , Trastornos Mentales , Estados UnidosRESUMEN
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.
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Procesos Mentales , Carrera , Microscopía por Crioelectrón , LigandosRESUMEN
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.
RESUMEN
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.
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Quirópteros , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Animales , Humanos , Enzima Convertidora de Angiotensina 2 , SARS-CoV-2/genética , Tropismo , Glicoproteína de la Espiga del Coronavirus , Anticuerpos AntiviralesRESUMEN
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.
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Enzima Convertidora de Angiotensina 2/química , Anticuerpos Antivirales/química , Evasión Inmune , Receptores de Coronavirus/química , SARS-CoV-2/química , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/química , Sustitución de Aminoácidos , Enzima Convertidora de Angiotensina 2/metabolismo , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/metabolismo , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/metabolismo , Deriva y Cambio Antigénico , Anticuerpos ampliamente neutralizantes/química , Anticuerpos ampliamente neutralizantes/inmunología , Anticuerpos ampliamente neutralizantes/metabolismo , Microscopía por Crioelectrón , Cristalografía por Rayos X , Humanos , Modelos Moleculares , Mutación , Unión Proteica , Conformación Proteica , Dominios Proteicos/genética , Dominios y Motivos de Interacción de Proteínas/genética , Receptores de Coronavirus/metabolismo , SARS-CoV-2/genética , SARS-CoV-2/fisiología , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunología , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
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.
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Enzima Convertidora de Angiotensina 2/metabolismo , Anticuerpos Antivirales/inmunología , Betacoronavirus/inmunología , Anticuerpos ampliamente neutralizantes/inmunología , COVID-19/terapia , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Enzima Convertidora de Angiotensina 2/química , Animales , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/metabolismo , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Antivirales/química , Anticuerpos Antivirales/metabolismo , Afinidad de Anticuerpos , Anticuerpos ampliamente neutralizantes/química , Anticuerpos ampliamente neutralizantes/metabolismo , Anticuerpos ampliamente neutralizantes/uso terapéutico , COVID-19/inmunología , Reacciones Cruzadas , Microscopía por Crioelectrón , Epítopos , Humanos , Evasión Inmune , Mesocricetus , Modelos Moleculares , Imitación Molecular , Mutación , Conformación Proteica , Dominios Proteicos , Receptores de Coronavirus/química , Receptores de Coronavirus/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
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.
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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.
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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.
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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.
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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.
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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.
Asunto(s)
Costos de la Atención en Salud , Cuidados Paliativos al Final de la Vida/economía , Hospitales para Enfermos Terminales/economía , Garantía de la Calidad de Atención de Salud/economía , Estudios Transversales , Humanos , Medicare/economía , Estados UnidosRESUMEN
La tetralogía de Fallot es la cardiopatía congénita cianótica más frecuente, su prevalencia es del 0,08% afectando aproximadamente a 1 de cada 8.500 nacidos vivos. El manejo de pacientes con cardiopatía congénita representa un desafío para el odontopediatra, ya que requiere conocimientos y habilidades específicas. La odontología de mínima intervención permite ofrecer a los pacientes un tratamiento gentil, mejorando el abordaje conductual ayudando a la adaptación del paciente al tratamiento dental. El objetivo de este reporte consiste describir el manejo estomatológico con odontología de mínima intervención en una paciente femenina de 5 años de edad con diagnóstico de tetralogía de Fallot. Conclusión: la odontología de mínima intervención fue eficaz para el tratamiento de paciente con cardiopatía congénita aportando herramientas significativas destinadas a mejorar la conducta, brindando tratamientos sencillos, rápidos y conservadores. Dando la posibilidad de este tipo de tratamientos en cualquier otro paciente con compromiso médico
A tetralogia de Fallot é a cardiopatia congênita cianótica mais comum, com uma prevalência de 0,08%, afetando aproximadamente 1 em 8.500 nascidos vivos. O tratamento de pacientes com cardiopatias congênitas representa um desafio para os dentistas pediátricos, pois requer conhecimentos e habilidades específicas. A odontologia de intervenção mínima permite oferecer aos pacientes um tratamento gentio, melhorando a abordagem comportamental e ajudando na adaptação do paciente ao tratamento odontológico. O objetivo deste relatório é descrever o tratamento estomatológico com intervenção odontológica mínima em um paciente de 5 anos diagnosticado com tetralogia de Fallot. Conclusão: A odontologia com intervenção mínima foi eficaz no tratamento de pacientes com doenças cardíacas congênitas, fornecendo ferramentas significativas destinadas a melhorar o comportamento, oferecendo tratamentos simples, rápidos e conservadores. Ela oferece a possibilidade deste tipo de tratamento em qualquer outro paciente com comprometimento médico
Tetralogy of Fallot is the most common cyanotic congenital heart disease, with a prevalence of 0,08%, affecting approximately 1 in every 8,500 live births. Treatment patients with congenital heart disease represents a challenge for pediatric dentists, it requires specific knowledge and skills. Minimal intervention dentistry allows offering patients a gentle treatment, improving the behavioral approach and helping the patient's adaptation to dental treatment. The aim of this report is to describe the management with minimal intervention dentistry in a 5-year-old female patient with a diagnosis of tetralogy of Fallot. Conclusion: Minimal intervention dentistry was effective in the treatment of patients with congenital heart disease, providing significant tools aimed at improving behavior, offering simple, fast and conservative treatments. It gives the possibility of this type of treatment in any other patient with medical compromise.