RESUMEN
SARS-CoV-2 can mutate and evade immunity, with consequences for efficacy of emerging vaccines and antibody therapeutics. Here, we demonstrate that the immunodominant SARS-CoV-2 spike (S) receptor binding motif (RBM) is a highly variable region of S and provide epidemiological, clinical, and molecular characterization of a prevalent, sentinel RBM mutation, N439K. We demonstrate N439K S protein has enhanced binding affinity to the hACE2 receptor, and N439K viruses have similar in vitro replication fitness and cause infections with similar clinical outcomes as compared to wild type. We show the N439K mutation confers resistance against several neutralizing monoclonal antibodies, including one authorized for emergency use by the US Food and Drug Administration (FDA), and reduces the activity of some polyclonal sera from persons recovered from infection. Immune evasion mutations that maintain virulence and fitness such as N439K can emerge within SARS-CoV-2 S, highlighting the need for ongoing molecular surveillance to guide development and usage of vaccines and therapeutics.
Asunto(s)
COVID-19/inmunología , Aptitud Genética , Evasión Inmune , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Enzima Convertidora de Angiotensina 2/química , Anticuerpos Neutralizantes/genética , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , COVID-19/virología , Humanos , Mutación , Filogenia , SARS-CoV-2/química , SARS-CoV-2/patogenicidad , Glicoproteína de la Espiga del Coronavirus/química , VirulenciaRESUMEN
Analysis of the specificity and kinetics of neutralizing antibodies (nAbs) elicited by SARS-CoV-2 infection is crucial for understanding immune protection and identifying targets for vaccine design. In a cohort of 647 SARS-CoV-2-infected subjects, we found that both the magnitude of Ab responses to SARS-CoV-2 spike (S) and nucleoprotein and nAb titers correlate with clinical scores. The receptor-binding domain (RBD) is immunodominant and the target of 90% of the neutralizing activity present in SARS-CoV-2 immune sera. Whereas overall RBD-specific serum IgG titers waned with a half-life of 49 days, nAb titers and avidity increased over time for some individuals, consistent with affinity maturation. We structurally defined an RBD antigenic map and serologically quantified serum Abs specific for distinct RBD epitopes leading to the identification of two major receptor-binding motif antigenic sites. Our results explain the immunodominance of the receptor-binding motif and will guide the design of COVID-19 vaccines and therapeutics.
Asunto(s)
Anticuerpos Neutralizantes/inmunología , Mapeo Epitopo/métodos , Glicoproteína de la Espiga del Coronavirus/inmunología , Enzima Convertidora de Angiotensina 2 , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/genética , Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/química , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Reacciones Antígeno-Anticuerpo , Betacoronavirus/inmunología , Betacoronavirus/aislamiento & purificación , Betacoronavirus/metabolismo , Sitios de Unión , COVID-19 , Infecciones por Coronavirus/patología , Infecciones por Coronavirus/virología , Epítopos/química , Epítopos/inmunología , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina A/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Inmunoglobulina M/sangre , Inmunoglobulina M/inmunología , Cinética , Simulación de Dinámica Molecular , Pandemias , Peptidil-Dipeptidasa A/química , Peptidil-Dipeptidasa A/metabolismo , Neumonía Viral/patología , Neumonía Viral/virología , Unión Proteica , Dominios Proteicos/inmunología , Estructura Cuaternaria de Proteína , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismoRESUMEN
Rapidly evolving influenza A viruses (IAVs) and influenza B viruses (IBVs) are major causes of recurrent lower respiratory tract infections. Current influenza vaccines elicit antibodies predominantly to the highly variable head region of haemagglutinin and their effectiveness is limited by viral drift1 and suboptimal immune responses2. Here we describe a neuraminidase-targeting monoclonal antibody, FNI9, that potently inhibits the enzymatic activity of all group 1 and group 2 IAVs, as well as Victoria/2/87-like, Yamagata/16/88-like and ancestral IBVs. FNI9 broadly neutralizes seasonal IAVs and IBVs, including the immune-evading H3N2 strains bearing an N-glycan at position 245, and shows synergistic activity when combined with anti-haemagglutinin stem-directed antibodies. Structural analysis reveals that D107 in the FNI9 heavy chain complementarity-determinant region 3 mimics the interaction of the sialic acid carboxyl group with the three highly conserved arginine residues (R118, R292 and R371) of the neuraminidase catalytic site. FNI9 demonstrates potent prophylactic activity against lethal IAV and IBV infections in mice. The unprecedented breadth and potency of the FNI9 monoclonal antibody supports its development for the prevention of influenza illness by seasonal and pandemic viruses.
Asunto(s)
Anticuerpos Antivirales , Especificidad de Anticuerpos , Virus de la Influenza A , Virus de la Influenza B , Vacunas contra la Influenza , Gripe Humana , Imitación Molecular , Neuraminidasa , Animales , Humanos , Ratones , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/uso terapéutico , Especificidad de Anticuerpos/inmunología , Arginina/química , Dominio Catalítico , Hemaglutininas Virales/inmunología , Virus de la Influenza A/clasificación , Virus de la Influenza A/enzimología , Virus de la Influenza A/inmunología , Subtipo H3N2 del Virus de la Influenza A/enzimología , Subtipo H3N2 del Virus de la Influenza A/inmunología , Virus de la Influenza B/clasificación , Virus de la Influenza B/enzimología , Virus de la Influenza B/inmunología , Vacunas contra la Influenza/química , Vacunas contra la Influenza/inmunología , Vacunas contra la Influenza/uso terapéutico , Gripe Humana/inmunología , Gripe Humana/prevención & control , Neuraminidasa/antagonistas & inhibidores , Neuraminidasa/química , Neuraminidasa/inmunología , Infecciones por Orthomyxoviridae/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Estaciones del Año , Ácidos Siálicos/químicaRESUMEN
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.
Asunto(s)
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 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.
Asunto(s)
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
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.
Asunto(s)
Anticuerpos ampliamente neutralizantes/inmunología , COVID-19/virología , Reacciones Cruzadas/inmunología , Evasión Inmune , SARS-CoV-2/clasificación , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/inmunología , Adulto , Anciano , Animales , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/química , Anticuerpos Antivirales/inmunología , Afinidad de Anticuerpos , Anticuerpos ampliamente neutralizantes/química , COVID-19/inmunología , Vacunas contra la COVID-19/química , Vacunas contra la COVID-19/inmunología , Línea Celular , Cricetinae , Epítopos de Linfocito B/química , Epítopos de Linfocito B/genética , Epítopos de Linfocito B/inmunología , Femenino , Humanos , Evasión Inmune/genética , Evasión Inmune/inmunología , Masculino , Mesocricetus , Persona de Mediana Edad , Modelos Moleculares , SARS-CoV-2/química , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Vacunología , Tratamiento Farmacológico de COVID-19RESUMEN
RluB catalyses the modification of U2605 to pseudouridine (Ψ) in a stem-loop at the peptidyl transferase center of Escherichia coli 23S rRNA. The homolog RluF is specific to the adjacent nucleotide in the stem, U2604. The 1.3 Å resolution crystal structure of the complex between the catalytic domain of RluB and the isolated substrate stem-loop, in which the target uridine is substituted by 5-fluorouridine (5-FU), reveals a covalent bond between the isomerized target base and tyrosine 140. The structure is compared with the catalytic domain alone determined at 2.5 Å resolution. The RluB-bound stem-loop has essentially the same secondary structure as in the ribosome, with a bulge at A2602, but with 5-FU2605 flipped into the active site. We showed earlier that RluF induced a frame-shift of the RNA, moving A2602 into the stem and translating its target, U2604, into the active site. A hydrogen-bonding network stabilizes the bulge in the RluB-RNA but is not conserved in RluF and so RluF cannot stabilize the bulge. On the basis of the covalent bond between enzyme and isomerized 5-FU we propose a Michael addition mechanism for pseudouridine formation that is consistent with all experimental data.
Asunto(s)
Proteínas de Escherichia coli/química , Transferasas Intramoleculares/química , ARN Ribosómico 23S/química , Apoenzimas/química , Arginina/química , Dominio Catalítico , Proteínas de Escherichia coli/metabolismo , Transferasas Intramoleculares/metabolismo , Modelos Moleculares , Conformación de Ácido Nucleico , Conformación Proteica , ARN Ribosómico 23S/metabolismo , Especificidad por Sustrato , Tirosina/química , Uridina/análogos & derivados , Uridina/química , Uridina/metabolismo , Agua/químicaRESUMEN
Memory B cells (MBCs) generate rapid antibody responses upon secondary encounter with a pathogen. Here, we investigated the kinetics, avidity, and cross-reactivity of serum antibodies and MBCs in 155 SARS-CoV-2 infected and vaccinated individuals over a 16-month time frame. SARS-CoV-2-specific MBCs and serum antibodies reached steady-state titers with comparable kinetics in infected and vaccinated individuals. Whereas MBCs of infected individuals targeted both prefusion and postfusion Spike (S), most vaccine-elicited MBCs were specific for prefusion S, consistent with the use of prefusion-stabilized S in mRNA vaccines. Furthermore, a large fraction of MBCs recognizing postfusion S cross-reacted with human betacoronaviruses. The avidity of MBC-derived and serum antibodies increased over time resulting in enhanced resilience to viral escape by SARS-CoV-2 variants, including Omicron BA.1 and BA.2 sublineages, albeit only partially for BA.4 and BA.5 sublineages. Overall, the maturation of high-affinity and broadly reactive MBCs provides the basis for effective recall responses to future SARS-CoV-2 variants.
RESUMEN
Currently circulating SARS-CoV-2 variants acquired convergent mutations at receptor-binding domain (RBD) hot spots. Their impact on viral infection, transmission, and efficacy of vaccines and therapeutics remains poorly understood. Here, we demonstrate that recently emerged BQ.1.1. and XBB.1 variants bind ACE2 with high affinity and promote membrane fusion more efficiently than earlier Omicron variants. Structures of the BQ.1.1 and XBB.1 RBDs bound to human ACE2 and S309 Fab (sotrovimab parent) explain the altered ACE2 recognition and preserved antibody binding through conformational selection. We show that sotrovimab binds avidly to all Omicron variants, promotes Fc-dependent effector functions and protects mice challenged with BQ.1.1, the variant displaying the greatest loss of neutralization. Moreover, in several donors vaccine-elicited plasma antibodies cross-react with and trigger effector functions against Omicron variants despite reduced neutralizing activity. Cross-reactive RBD-directed human memory B cells remained dominant even after two exposures to Omicron spikes, underscoring persistent immune imprinting. Our findings suggest that this previously overlooked class of cross-reactive antibodies, exemplified by S309, may contribute to protection against disease caused by emerging variants through elicitation of effector functions.
RESUMEN
The mechanism of how full length Tat (aa 1-86) crosses artificial lipid membranes was elucidated by means of fluorescence spectroscopy and fluorescence microscopy. It was shown that full length Tat (aa 1-86) neither forms pores in large unilamellar vesicles (LUVs) nor in giant unilamellar vesicles (GUVs) composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). In contrast, an N-terminally truncated Tat protein (aa 35-86) that lacks the structurally defined proline- and cysteine-rich region as well as the highly conserved tryptophan residue at position 11 generates pores in artificial POPC-membranes, through which a water-soluble dye up to a size of 10kDa can pass. By means of fluorescence microscopy, the transfer of fluorescently labeled full length Tat across POPC-bilayers was unambiguously visualized with a concomitant accumulation of the protein in the membrane interface. However, if the dye was attached to the protein, also pore formation was induced. The size of the pores was, however smaller than the protein size, i.e. the labeled protein with a mass of 11.6kDa passed the membrane, while a fluorescent dye with a mass of 10kDa was excluded from the vesicles' interior. The results demonstrate that pore formation is not the prime mechanism by which full length Tat crosses a membrane.
Asunto(s)
Productos del Gen tat del Virus de la Inmunodeficiencia Humana/química , Microscopía Confocal , Microscopía Fluorescente , Fosfatidilcolinas/química , Transporte de Proteínas , Liposomas Unilamelares/químicaRESUMEN
Viruses manipulate multiple processes of the host cell machinery in order to replicate successfully in the infected cell. Among these, stimulation of transcription of the viral genes is crucial for lentiviruses such as HIV for increased protein expression levels and generation of escape mutants. The transactivation response (TAR) element at the 5'-end of HIV, SIV, BIV, EIAV or JDV retroviruses forms a unique RNA based promoter element that together with the transcription activator protein Tat stimulates viral gene expression at the level of transcription elongation. TAR is a double stranded non-coding RNA of typically 24-40 nucleotides length. Together with Tat it interacts with the Cyclin T subunit of the positive transcription elongation factor P-TEFb to recruit Cyclin T and its corresponding Cyclin-dependent kinase Cdk9 to the RNA polymerase II. In vitro formations of these Tat-TAR containing ribonucleoprotein complexes are a key requisite for biochemical characterizations and interaction studies that eventually will allow structural analyses. Here, we describe purification methods of the different factors employed and chromatography techniques that yield highly specific complex assemblies suitable for crystallization.
Asunto(s)
Duplicado del Terminal Largo de VIH , VIH-1/metabolismo , Ribonucleoproteínas/metabolismo , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/metabolismo , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Cromatografía en Gel , Ciclina T/genética , Ciclina T/metabolismo , Ensayo de Cambio de Movilidad Electroforética , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Cuaternaria de Proteína , Estructura Terciaria de Proteína , ARN no Traducido/química , ARN no Traducido/metabolismo , ARN Viral/química , ARN Viral/metabolismo , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Ribonucleoproteínas/química , Alineación de Secuencia , Productos del Gen tat del Virus de la Inmunodeficiencia Humana/genéticaRESUMEN
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.
Asunto(s)
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
Memory B cells (MBCs) generate rapid antibody responses upon secondary encounter with a pathogen. Here, we investigated the kinetics, avidity and cross-reactivity of serum antibodies and MBCs in 155 SARS-CoV-2 infected and vaccinated individuals over a 16-month timeframe. SARS-CoV-2-specific MBCs and serum antibodies reached steady-state titers with comparable kinetics in infected and vaccinated individuals. Whereas MBCs of infected individuals targeted both pre- and postfusion Spike (S), most vaccine-elicited MBCs were specific for prefusion S, consistent with the use of prefusion-stabilized S in mRNA vaccines. Furthermore, a large fraction of MBCs recognizing postfusion S cross-reacted with human betacoronaviruses. The avidity of MBC-derived and serum antibodies increased over time resulting in enhanced resilience to viral escape by SARS-CoV-2 variants, including Omicron BA.1 and BA.2 sub-lineages, albeit only partially for BA.4 and BA.5 sublineages. Overall, the maturation of high-affinity and broadly-reactive MBCs provides the basis for effective recall responses to future SARS-CoV-2 variants.
RESUMEN
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant of concern comprises several sublineages, with BA.2 and BA.2.12.1 having replaced the previously dominant BA.1 and with BA.4 and BA.5 increasing in prevalence worldwide. We show that the large number of Omicron sublineage spike mutations leads to enhanced angiotensin-converting enzyme 2 (ACE2) binding, reduced fusogenicity, and severe dampening of plasma neutralizing activity elicited by infection or seven clinical vaccines relative to the ancestral virus. Administration of a homologous or heterologous booster based on the Wuhan-Hu-1 spike sequence markedly increased neutralizing antibody titers and breadth against BA.1, BA.2, BA.2.12.1, BA.4, and BA.5 across all vaccines evaluated. Our data suggest that although Omicron sublineages evade polyclonal neutralizing antibody responses elicited by primary vaccine series, vaccine boosters may provide sufficient protection against Omicron-induced severe disease.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , Vacunas contra la COVID-19 , COVID-19 , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Anticuerpos Neutralizantes/sangre , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , COVID-19/sangre , COVID-19/prevención & control , Vacunas contra la COVID-19/inmunología , Humanos , Inmunización Secundaria , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunologíaRESUMEN
Patients on dialysis are at risk of severe course of SARS-CoV-2 infection. Understanding the neutralizing activity and coverage of SARS-CoV-2 variants of vaccine-elicited antibodies is required to guide prophylactic and therapeutic COVID-19 interventions in this frail population. By analyzing plasma samples from 130 hemodialysis and 13 peritoneal dialysis patients after two doses of BNT162b2 or mRNA-1273 vaccines, we found that 35% of the patients had low-level or undetectable IgG antibodies to SARS-CoV-2 Spike (S). Neutralizing antibodies against the vaccine-matched SARS-CoV-2 and Delta variant were low or undetectable in 49% and 77% of patients, respectively, and were further reduced against other emerging variants. The fraction of non-responding patients was higher in SARS-CoV-2-naïve hemodialysis patients immunized with BNT162b2 (66%) than those immunized with mRNA-1273 (23%). The reduced neutralizing activity correlated with low antibody avidity. Patients followed up to 7 months after vaccination showed a rapid decay of the antibody response with an average 21- and 10-fold reduction of neutralizing antibodies to vaccine-matched SARS-CoV-2 and Delta variant, which increased the fraction of non-responders to 84% and 90%, respectively. These data indicate that dialysis patients should be prioritized for additional vaccination boosts. Nevertheless, their antibody response to SARS-CoV-2 must be continuously monitored to adopt the best prophylactic and therapeutic strategy.
Asunto(s)
Anticuerpos Neutralizantes/inmunología , Pruebas de Neutralización , Diálisis Renal , SARS-CoV-2/inmunología , Vacunación , Animales , Anticuerpos Neutralizantes/sangre , Afinidad de Anticuerpos , Células CHO , Vacunas contra la COVID-19/inmunología , Estudios de Casos y Controles , Cricetulus , Relación Dosis-Respuesta Inmunológica , Estudios de Seguimiento , Células HEK293 , Humanos , Inmunoglobulina G/sangre , Factores de Riesgo , Vacunas de ARNm/inmunologíaRESUMEN
Science education and research have the potential to drive profound change in low- and middle-income countries (LMICs) through encouraging innovation, attracting industry, and creating job opportunities. However, in LMICs, research capacity is often limited, and acquisition of funding and access to state-of-the-art technologies is challenging. The Alliance for Global Health and Science (the Alliance) was founded as a partnership between the University of California, Berkeley (USA) and Makerere University (Uganda), with the goal of strengthening Makerere University's capacity for bioscience research. The flagship program of the Alliance partnership is the MU/UCB Biosciences Training Program, an in-country, hands-on workshop model that trains a large number of students from Makerere University in infectious disease and molecular biology research. This approach nucleates training of larger and more diverse groups of students, development of mentoring and bi-directional research partnerships, and support of the local economy. Here, we describe the project, its conception, implementation, challenges, and outcomes of bioscience research workshops. We aim to provide a blueprint for workshop implementation, and create a valuable resource for bioscience research capacity strengthening in LMICs.
Asunto(s)
Países en Desarrollo , Salud Global , Creación de Capacidad , Humanos , Pobreza , Estudiantes , UniversidadesRESUMEN
An ideal anti-SARS-CoV-2 antibody would resist viral escape 1-3 , have activity against diverse SARS-related coronaviruses 4-7 , and be highly protective through viral neutralization 8-11 and effector functions 12,13 . Understanding how these properties relate to each other and vary across epitopes would aid development of antibody therapeutics 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), including S309 4 , the parental antibody of the late-stage clinical antibody VIR-7831. We observe a tradeoff between SARS-CoV-2 in vitro neutralization potency and breadth of binding across SARS-related coronaviruses. Nevertheless, we identify several neutralizing antibodies with exceptional breadth and resistance to escape, including a new antibody (S2H97) that binds with high affinity to all SARS-related coronavirus clades via a unique RBD epitope centered on residue E516. S2H97 and other escape-resistant antibodies have high binding affinity and target functionally constrained RBD residues. We find that antibodies targeting the ACE2 receptor binding motif (RBM) typically have poor breadth and are readily escaped by mutations despite high neutralization potency, but we identify one potent RBM antibody (S2E12) with breadth across sarbecoviruses closely related to SARS-CoV-2 and with a high barrier to viral escape. These data highlight functional diversity among antibodies targeting the RBD and identify epitopes and features to prioritize for antibody and vaccine development against the current and potential future pandemics.
RESUMEN
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.