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Prevention of viral escape and increased coverage against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern require therapeutic monoclonal antibodies (mAbs) targeting multiple sites of vulnerability on the coronavirus spike glycoprotein. Here we identify several potent neutralizing antibodies directed against either the N-terminal domain (NTD) or the receptor-binding domain (RBD) of the spike protein. Administered in combinations, these mAbs provided low-dose protection against SARS-CoV-2 infection in the K18-human angiotensin-converting enzyme 2 mouse model, using both neutralization and Fc effector antibody functions. The RBD mAb WRAIR-2125, which targets residue F486 through a unique heavy-chain and light-chain pairing, demonstrated potent neutralizing activity against all major SARS-CoV-2 variants of concern. In combination with NTD and other RBD mAbs, WRAIR-2125 also prevented viral escape. These data demonstrate that NTD/RBD mAb combinations confer potent protection, likely leveraging complementary mechanisms of viral inactivation and clearance.
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Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , COVID-19/inmunología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Monoclonales/metabolismo , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/metabolismo , Sitios de Unión/genética , COVID-19/metabolismo , COVID-19/prevención & control , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Mapeo Epitopo , Epítopos/química , Epítopos/inmunología , Epítopos/metabolismo , Humanos , Ratones Transgénicos , Pruebas de Neutralización , Unión Proteica , Conformación Proteica , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Homología de Secuencia de Aminoácido , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/metabolismo , Análisis de SupervivenciaRESUMEN
The HIV-1-envelope (Env) trimer is covered by a glycan shield of â¼90 N-linked oligosaccharides, which comprises roughly half its mass and is a key component of HIV evasion from humoral immunity. To understand how antibodies can overcome the barriers imposed by the glycan shield, we crystallized fully glycosylated Env trimers from clades A, B, and G, visualizing the shield at 3.4-3.7 Å resolution. These structures reveal the HIV-1-glycan shield to comprise a network of interlocking oligosaccharides, substantially ordered by glycan crowding, that encase the protein component of Env and enable HIV-1 to avoid most antibody-mediated neutralization. The revealed features delineate a taxonomy of N-linked glycan-glycan interactions. Crowded and dispersed glycans are differently ordered, conserved, processed, and recognized by antibody. The structures, along with glycan-array binding and molecular dynamics, reveal a diversity in oligosaccharide affinity and a requirement for accommodating glycans among known broadly neutralizing antibodies that target the glycan-shielded trimer.
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VIH-1/química , Productos del Gen env del Virus de la Inmunodeficiencia Humana/química , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Antivirales/metabolismo , Cristalografía por Rayos X , Glicosilación , VIH-1/clasificación , VIH-1/inmunología , Evasión Inmune , Modelos Moleculares , Simulación de Dinámica Molecular , Polisacáridos/análisis , Polisacáridos/metabolismoRESUMEN
Antibodies capable of neutralizing divergent influenza A viruses could form the basis of a universal vaccine. Here, from subjects enrolled in an H5N1 DNA/MIV-prime-boost influenza vaccine trial, we sorted hemagglutinin cross-reactive memory B cells and identified three antibody classes, each capable of neutralizing diverse subtypes of group 1 and group 2 influenza A viruses. Co-crystal structures with hemagglutinin revealed that each class utilized characteristic germline genes and convergent sequence motifs to recognize overlapping epitopes in the hemagglutinin stem. All six analyzed subjects had sequences from at least one multidonor class, and-in half the subjects-multidonor-class sequences were recovered from >40% of cross-reactive B cells. By contrast, these multidonor-class sequences were rare in published antibody datasets. Vaccination with a divergent hemagglutinin can thus increase the frequency of B cells encoding broad influenza A-neutralizing antibodies. We propose the sequence signature-quantified prevalence of these B cells as a metric to guide universal influenza A immunization strategies.
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Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Adulto , Secuencia de Aminoácidos , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/genética , Anticuerpos Antivirales/química , Anticuerpos Antivirales/genética , Linfocitos B/inmunología , Epítopos de Linfocito B , Femenino , Reordenamiento Génico de Cadena Pesada de Linfocito B , Humanos , Memoria Inmunológica , Subtipo H5N1 del Virus de la Influenza A/inmunología , Masculino , Persona de Mediana Edad , Modelos Moleculares , Estructura Terciaria de Proteína , Relación Estructura-Actividad , Adulto JovenRESUMEN
Mitochondrial inheritance, genome maintenance and metabolic adaptation depend on organelle fission by dynamin-related protein 1 (DRP1) and its mitochondrial receptors. DRP1 receptors include the paralogues mitochondrial dynamics proteins of 49 and 51 kDa (MID49 and MID51) and mitochondrial fission factor (MFF); however, the mechanisms by which these proteins recruit and regulate DRP1 are unknown. Here we present a cryo-electron microscopy structure of full-length human DRP1 co-assembled with MID49 and an analysis of structure- and disease-based mutations. We report that GTP induces a marked elongation and rotation of the GTPase domain, bundle-signalling element and connecting hinge loops of DRP1. In this conformation, a network of multivalent interactions promotes the polymerization of a linear DRP1 filament with MID49 or MID51. After co-assembly, GTP hydrolysis and exchange lead to MID receptor dissociation, filament shortening and curling of DRP1 oligomers into constricted and closed rings. Together, these views of full-length, receptor- and nucleotide-bound conformations reveal how DRP1 performs mechanical work through nucleotide-driven allostery.
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Proteínas Quinasas Asociadas a Muerte Celular/metabolismo , Proteínas Quinasas Asociadas a Muerte Celular/ultraestructura , Proteínas Mitocondriales/metabolismo , Proteínas Mitocondriales/ultraestructura , Factores de Elongación de Péptidos/metabolismo , Factores de Elongación de Péptidos/ultraestructura , Regulación Alostérica , Sitios de Unión/genética , Microscopía por Crioelectrón , Proteínas Quinasas Asociadas a Muerte Celular/química , Proteínas Quinasas Asociadas a Muerte Celular/genética , GTP Fosfohidrolasas/química , GTP Fosfohidrolasas/genética , GTP Fosfohidrolasas/metabolismo , GTP Fosfohidrolasas/ultraestructura , Guanosina Trifosfato/metabolismo , Humanos , Hidrólisis , Proteínas Mitocondriales/química , Modelos Moleculares , Mutación , Factores de Elongación de Péptidos/química , Fosforilación , Dominios Proteicos , Rotación , Relación Estructura-ActividadRESUMEN
Emergence of novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need for next-generation vaccines able to elicit broad and durable immunity. Here we report the evaluation of a ferritin nanoparticle vaccine displaying the receptor-binding domain of the SARS-CoV-2 spike protein (RFN) adjuvanted with Army Liposomal Formulation QS-21 (ALFQ). RFN vaccination of macaques using a two-dose regimen resulted in robust, predominantly Th1 CD4+ T cell responses and reciprocal peak mean serum neutralizing antibody titers of 14,000 to 21,000. Rapid control of viral replication was achieved in the upper and lower airways of animals after high-dose SARS-CoV-2 respiratory challenge, with undetectable replication within 4 d in seven of eight animals receiving 50 µg of RFN. Cross-neutralization activity against SARS-CoV-2 variant B.1.351 decreased only approximately twofold relative to WA1/2020. In addition, neutralizing, effector antibody and cellular responses targeted the heterotypic SARS-CoV-1, highlighting the broad immunogenicity of RFN-ALFQ for SARS-CoV-like Sarbecovirus vaccine development.
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Vacunas contra la COVID-19/administración & dosificación , COVID-19/virología , Macaca mulatta/inmunología , Nanopartículas/química , Receptores Virales/metabolismo , SARS-CoV-2/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Animales , Anticuerpos Neutralizantes/biosíntesis , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/biosíntesis , Anticuerpos Antivirales/inmunología , COVID-19/prevención & control , Vacunas contra la COVID-19/inmunología , Ferritinas/química , SARS-CoV-2/metabolismo , Linfocitos T/inmunologíaRESUMEN
Parainfluenza virus types 1-4 (PIV1-4) are highly infectious human pathogens, of which PIV3 is most commonly responsible for severe respiratory illness in newborns, elderly, and immunocompromised individuals. To obtain a vaccine effective against all four PIV types, we engineered mutations in each of the four PIV fusion (F) glycoproteins to stabilize their metastable prefusion states, as such stabilization had previously enabled the elicitation of high-titer neutralizing antibodies against the related respiratory syncytial virus. A cryoelectron microscopy structure of an engineered PIV3 F prefusion-stabilized trimer, bound to the prefusion-specific antibody PIA174, revealed atomic-level details for how introduced mutations improved stability as well as how a single PIA174 antibody recognized the trimeric apex of prefusion PIV3 F. Nine combinations of six newly identified disulfides and two cavity-filling mutations stabilized the prefusion PIV3 F immunogens and induced 200- to 500-fold higher neutralizing titers in mice than were elicited by PIV3 F in the postfusion conformation. For PIV1, PIV2, and PIV4, we also obtained stabilized prefusion Fs, for which prefusion versus postfusion titers were 2- to 20-fold higher. Elicited murine responses were PIV type-specific, with little cross-neutralization of other PIVs. In nonhuman primates (NHPs), quadrivalent immunization with prefusion-stabilized Fs from PIV1-4 consistently induced potent neutralizing responses against all four PIVs. For PIV3, the average elicited NHP titer from the quadrivalent immunization was more than fivefold higher than any titer observed in a cohort of over 100 human adults, highlighting the ability of a prefusion-stabilized immunogen to elicit especially potent neutralization.
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Virus de la Parainfluenza 1 Humana/inmunología , Virus de la Parainfluenza 2 Humana/inmunología , Virus de la Parainfluenza 3 Humana/inmunología , Virus de la Parainfluenza 4 Humana/inmunología , Infecciones por Respirovirus/inmunología , Proteínas Virales de Fusión/química , Vacunas Virales/química , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Microscopía por Crioelectrón , Femenino , Humanos , Macaca mulatta , Masculino , Ratones , Virus de la Parainfluenza 1 Humana/química , Virus de la Parainfluenza 1 Humana/genética , Virus de la Parainfluenza 2 Humana/química , Virus de la Parainfluenza 2 Humana/genética , Virus de la Parainfluenza 3 Humana/química , Virus de la Parainfluenza 3 Humana/genética , Virus de la Parainfluenza 4 Humana/química , Virus de la Parainfluenza 4 Humana/genética , Infecciones por Virus Sincitial Respiratorio , Infecciones por Respirovirus/prevención & control , Infecciones por Respirovirus/virología , Proteínas Virales de Fusión/administración & dosificación , Proteínas Virales de Fusión/genética , Proteínas Virales de Fusión/inmunología , Vacunas Virales/administración & dosificación , Vacunas Virales/genética , Vacunas Virales/inmunologíaRESUMEN
Background: Accelerated orthodontic treatment has gained popularity in recent years as patients seek shorter treatment durations. Microosteoperforations (MOPs) have emerged as a minimally invasive technique to expedite tooth movement. This study aims to compare the effectiveness of MOPs in accelerating orthodontic treatment with conventional methods. Materials and Methods: A randomized controlled trial was conducted on 60 orthodontic patients requiring dental alignment. The participants were divided into two groups: Group A (MOPs) and Group B (conventional orthodontic treatment). In Group A, MOPs were performed at the beginning of the treatment. Both groups received monthly orthodontic adjustments. Treatment duration, rate of tooth movement, and patient discomfort were measured and compared between the two groups. Results: The study found that in Group A, the treatment duration was reduced by 30% compared to Group B (P < 0.05). The rate of tooth movement in the MOPs group was 1.5 times higher than the conventional group (P < 0.01). Additionally, patient-reported discomfort levels were similar between the two groups. No adverse events related to MOPs were observed during the study. Conclusion: MOPs significantly accelerate orthodontic treatment, reducing treatment duration by 30% and increasing the rate of tooth movement by 1.5 times compared to conventional methods. Importantly, MOPs are well-tolerated by patients, making them a valuable option for expediting orthodontic treatment with minimal discomfort. This study highlights the potential benefits of integrating MOPs into orthodontic practice to improve treatment efficiency and patient satisfaction.
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An effective HIV-1 vaccine must elicit broadly neutralizing antibodies (bnAbs) against highly diverse Envelope glycoproteins (Env). Since Env with the longest hypervariable (HV) loops is more resistant to the cognate bnAbs than Env with shorter HV loops, we redesigned hypervariable loops for updated Env consensus sequences of subtypes B and C and CRF01_AE. Using modeling with AlphaFold2, we reduced the length of V1, V2, and V5 HV loops while maintaining the integrity of the Env structure and glycan shield, and modified the V4 HV loop. Spacers are designed to limit strain-specific targeting. All updated Env are infectious as pseudoviruses. Preliminary structural characterization suggests that the modified HV loops have a limited impact on Env's conformation. Binding assays show improved binding to modified subtype B and CRF01_AE Env but not to subtype C Env. Neutralization assays show increases in sensitivity to bnAbs, although not always consistently across clades. Strikingly, the HV loop modification renders the resistant CRF01_AE Env sensitive to 10-1074 despite the absence of a glycan at N332.
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Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , VIH-1 , Productos del Gen env del Virus de la Inmunodeficiencia Humana , VIH-1/inmunología , Humanos , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/química , Productos del Gen env del Virus de la Inmunodeficiencia Humana/metabolismo , Anticuerpos Anti-VIH/inmunología , Anticuerpos Neutralizantes/inmunología , Vacunas contra el SIDA/inmunología , Pruebas de Neutralización , Células HEK293 , Secuencia de Consenso , Infecciones por VIH/virología , Infecciones por VIH/inmunología , Unión Proteica , Epítopos/inmunologíaRESUMEN
The repeat emergence of SARS-CoV-2 variants of concern (VoC) with decreased susceptibility to vaccine-elicited antibodies highlights the need to develop next-generation vaccine candidates that confer broad protection. Here we describe the antibody response induced by the SARS-CoV-2 Spike Ferritin Nanoparticle (SpFN) vaccine candidate adjuvanted with the Army Liposomal Formulation including QS21 (ALFQ) in non-human primates. By isolating and characterizing several monoclonal antibodies directed against the Spike Receptor Binding Domain (RBD), N-Terminal Domain (NTD), or the S2 Domain, we define the molecular recognition of vaccine-elicited cross-reactive monoclonal antibodies (mAbs) elicited by SpFN. We identify six neutralizing antibodies with broad sarbecovirus cross-reactivity that recapitulate serum polyclonal antibody responses. In particular, RBD mAb WRAIR-5001 binds to the conserved cryptic region with high affinity to sarbecovirus clades 1 and 2, including Omicron variants, while mAb WRAIR-5021 offers complete protection from B.1.617.2 (Delta) in a murine challenge study. Our data further highlight the ability of SpFN vaccination to stimulate cross-reactive B cells targeting conserved regions of the Spike with activity against SARS CoV-1 and SARS-CoV-2 variants.
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Nanopartículas , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Animales , Ratones , Anticuerpos Neutralizantes , Macaca mulatta , Vacunación , Anticuerpos Antivirales , Anticuerpos Monoclonales , Vacunas contra la COVID-19 , Ferritinas , Glicoproteína de la Espiga del Coronavirus/genéticaRESUMEN
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines demonstrate reduced protection against acquisition of BA.5 subvariant but are still effective against severe disease. However, immune correlates of protection against BA.5 remain unknown. We report the immunogenicity and protective efficacy of vaccine regimens consisting of the vector-based Ad26.COV2.S vaccine and the adjuvanted spike ferritin nanoparticle (SpFN) vaccine against a high-dose, mismatched Omicron BA.5 challenge in macaques. The SpFNx3 and Ad26 + SpFNx2 regimens elicit higher antibody responses than Ad26x3, whereas the Ad26 + SpFNx2 and Ad26x3 regimens induce higher CD8 T cell responses than SpFNx3. The Ad26 + SpFNx2 regimen elicits the highest CD4 T cell responses. All three regimens suppress peak and day 4 viral loads in the respiratory tract, which correlate with both humoral and cellular immune responses. This study demonstrates that both homologous and heterologous regimens involving Ad26.COV2.S and SpFN vaccines provide robust protection against a mismatched BA.5 challenge in macaques.
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COVID-19 , Nanopartículas , Vacunas , Humanos , Animales , Macaca , Ad26COVS1 , COVID-19/prevención & control , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , FerritinasRESUMEN
Despite rapid and ongoing vaccine and therapeutic development, SARS-CoV-2 continues to evolve and evade, presenting a need for next-generation diverse therapeutic modalities. Here we show that nurse sharks immunized with SARS-CoV-2 recombinant receptor binding domain (RBD), RBD-ferritin (RFN), or spike protein ferritin nanoparticle (SpFN) immunogens elicit a set of new antigen receptor antibody (IgNAR) molecules that target two non-overlapping conserved epitopes on the spike RBD. Representative shark antibody variable NAR-Fc chimeras (ShAbs) targeting either of the two epitopes mediate cell-effector functions, with high affinity to all SARS-CoV-2 viral variants of concern, including the divergent Omicron strains. The ShAbs potently cross-neutralize SARS-CoV-2 WA-1, Alpha, Beta, Delta, Omicron BA.1 and BA.5, and SARS-CoV-1 pseudoviruses, and confer protection against SARS-CoV-2 challenge in the K18-hACE2 transgenic mouse model. Structural definition of the RBD-ShAb01-ShAb02 complex enabled design and production of multi-specific nanobodies with enhanced neutralization capacity, and picomolar affinity to divergent sarbecovirus clade 1a, 1b and 2 RBD molecules. These shark nanobodies represent potent immunotherapeutics both for current use, and future sarbecovirus pandemic preparation.
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COVID-19 , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Anticuerpos de Dominio Único , Animales , Ratones , Anticuerpos Neutralizantes , Anticuerpos Antivirales , COVID-19/prevención & control , Epítopos , Ferritinas/genética , Fragmentos Fc de Inmunoglobulinas , Ratones Transgénicos , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , TiburonesRESUMEN
Emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and waning immunity call for next-generation vaccine strategies. Here, we assessed the immunogenicity and protective efficacy of two SARS-CoV-2 vaccines targeting the WA1/2020 spike protein, Ad26.COV2.S (Ad26) and Spike ferritin Nanoparticle (SpFN), in nonhuman primates, delivered as either a homologous (SpFN/SpFN and Ad26/Ad26) or heterologous (Ad26/SpFN) prime-boost regimen. The Ad26/SpFN regimen elicited the highest CD4 T cell and memory B cell responses, the SpFN/SpFN regimen generated the highest binding and neutralizing antibody responses, and the Ad26/Ad26 regimen generated the most robust CD8 T cell responses. Despite these differences, protective efficacy against SARS-CoV-2 Omicron BA.1 challenge was similar for all three regimens. After challenge, all vaccinated monkeys showed significantly reduced peak and day 4 viral loads in both bronchoalveolar lavage and nasal swabs as compared with sham animals. The efficacy conferred by these three immunologically distinct vaccine regimens suggests that both humoral and cellular immunity contribute to protection against SARS-CoV-2 Omicron challenge.
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The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants stresses the continued need for next-generation vaccines that confer broad protection against coronavirus disease 2019 (COVID-19). We developed and evaluated an adjuvanted SARS-CoV-2 spike ferritin nanoparticle (SpFN) vaccine in nonhuman primates. High-dose (50 µg) SpFN vaccine, given twice 28 days apart, induced a Th1-biased CD4 T cell helper response and elicited neutralizing antibodies against SARS-CoV-2 wild-type and variants of concern, as well as against SARS-CoV-1. These potent humoral and cell-mediated immune responses translated into rapid elimination of replicating virus in the upper and lower airways and lung parenchyma of nonhuman primates following high-dose SARS-CoV-2 respiratory challenge. The immune response elicited by SpFN vaccination and resulting efficacy in nonhuman primates supports the utility of SpFN as a vaccine candidate for SARS-causing betacoronaviruses.
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COVID-19 , Nanopartículas , Animales , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Vacunas contra la COVID-19 , Ferritinas , Humanos , Inmunidad , Macaca mulatta , SARS-CoV-2 , Glicoproteína de la Espiga del CoronavirusRESUMEN
The COVID-19 pandemic has had a staggering impact on social, economic, and public health systems worldwide. Vaccine development and mobilization against SARS-CoV-2 (the etiologic agent of COVID-19) has been rapid. However, novel strategies are still necessary to slow the pandemic, and this includes new approaches to vaccine development and/or delivery that will improve vaccination compliance and demonstrate efficacy against emerging variants. Here, we report on the immunogenicity and efficacy of a SARS-CoV-2 vaccine comprising stabilized, pre-fusion spike protein trimers displayed on a ferritin nanoparticle (SpFN) adjuvanted with either conventional aluminum hydroxide or the Army Liposomal Formulation QS-21 (ALFQ) in a cynomolgus macaque COVID-19 model. Vaccination resulted in robust cell-mediated and humoral responses and a significant reduction in lung lesions following SARS-CoV-2 infection. The strength of the immune response suggests that dose sparing through reduced or single dosing in primates may be possible with this vaccine. Overall, the data support further evaluation of SpFN as a SARS-CoV-2 protein-based vaccine candidate with attention to fractional dosing and schedule optimization.
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The emergence of SARS-CoV-2 variants of concern (VOC) requires adequate coverage of vaccine protection. We evaluated whether a SARS-CoV-2 spike ferritin nanoparticle vaccine (SpFN), adjuvanted with the Army Liposomal Formulation QS21 (ALFQ), conferred protection against the Alpha (B.1.1.7), and Beta (B.1.351) VOCs in Syrian golden hamsters. SpFN-ALFQ was administered as either single or double-vaccination (0 and 4 week) regimens, using a high (10 µg) or low (0.2 µg) dose. Animals were intranasally challenged at week 11. Binding antibody responses were comparable between high- and low-dose groups. Neutralizing antibody titers were equivalent against WA1, B.1.1.7, and B.1.351 variants following two high dose vaccinations. Dose-dependent SpFN-ALFQ vaccination protected against SARS-CoV-2-induced disease and viral replication following intranasal B.1.1.7 or B.1.351 challenge, as evidenced by reduced weight loss, lung pathology, and lung and nasal turbinate viral burden. These data support the development of SpFN-ALFQ as a broadly protective, next-generation SARS-CoV-2 vaccine.
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Emergence of novel variants of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) underscores the need for next-generation vaccines able to elicit broad and durable immunity. Here we report the evaluation of a ferritin nanoparticle vaccine displaying the receptor-binding domain of the SARS-CoV-2 spike protein (RFN) adjuvanted with Army Liposomal Formulation QS-21 (ALFQ). RFN vaccination of macaques using a two-dose regimen resulted in robust, predominantly Th1 CD4+ T cell responses and reciprocal peak mean neutralizing antibody titers of 14,000-21,000. Rapid control of viral replication was achieved in the upper and lower airways of animals after high-dose SARS-CoV-2 respiratory challenge, with undetectable replication within four days in 7 of 8 animals receiving 50 µg RFN. Cross-neutralization activity against SARS-CoV-2 variant B.1.351 decreased only â¼2-fold relative to USA-WA1. In addition, neutralizing, effector antibody and cellular responses targeted the heterotypic SARS-CoV-1, highlighting the broad immunogenicity of RFN-ALFQ for SARS-like betacoronavirus vaccine development. SIGNIFICANCE STATEMENT: The emergence of SARS-CoV-2 variants of concern (VOC) that reduce the efficacy of current COVID-19 vaccines is a major threat to pandemic control. We evaluate a SARS-CoV-2 Spike receptor-binding domain ferritin nanoparticle protein vaccine (RFN) in a nonhuman primate challenge model that addresses the need for a next-generation, efficacious vaccine with increased pan-SARS breadth of coverage. RFN, adjuvanted with a liposomal-QS21 formulation (ALFQ), elicits humoral and cellular immune responses exceeding those of current vaccines in terms of breadth and potency and protects against high-dose respiratory tract challenge. Neutralization activity against the B.1.351 VOC within two-fold of wild-type virus and against SARS-CoV-1 indicate exceptional breadth. Our results support consideration of RFN for SARS-like betacoronavirus vaccine development.
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The need for SARS-CoV-2 next-generation vaccines has been highlighted by the rise of variants of concern (VoC) and the long-term threat of other coronaviruses. Here, we designed and characterized four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of prefusion Spike (S), S1 and RBD. These immunogens induced robust S-binding, ACE2-inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2 in mice. A Spike-ferritin nanoparticle (SpFN) vaccine elicited neutralizing titers more than 20-fold higher than convalescent donor serum, following a single immunization, while RBD-Ferritin nanoparticle (RFN) immunogens elicited similar responses after two immunizations. Passive transfer of IgG purified from SpFN- or RFN-immunized mice protected K18-hACE2 transgenic mice from a lethal SARS-CoV-2 virus challenge. Furthermore, SpFN- and RFN-immunization elicited ACE2 blocking activity and neutralizing ID50 antibody titers >2,000 against SARS-CoV-1, along with high magnitude neutralizing titers against major VoC. These results provide design strategies for pan-coronavirus vaccine development. HIGHLIGHTS: Iterative structure-based design of four Spike-domain Ferritin nanoparticle classes of immunogensSpFN-ALFQ and RFN-ALFQ immunization elicits potent neutralizing activity against SARS-CoV-2, variants of concern, and SARS-CoV-1Passively transferred IgG from immunized C57BL/6 mice protects K18-hACE2 mice from lethal SARS-CoV-2 challenge.
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The emergence of SARS-CoV-2 variants of concern (VOC) requires adequate coverage of vaccine protection. We evaluated whether a spike ferritin nanoparticle vaccine (SpFN), adjuvanted with the Army Liposomal Formulation QS21 (ALFQ), conferred protection against the B.1.1.7 and B.1.351 VOCs in Syrian golden hamsters. SpFN-ALFQ was administered as either single or double-vaccination (0 and 4 week) regimens, using a high (10 µg) or low (0.2 µg) immunogen dose. Animals were intranasally challenged at week 11. Binding antibody responses were comparable between high- and low-dose groups. Neutralizing antibody titers were equivalent against WA1, B.1.1.7, and B.1.351 variants following two high dose two vaccinations. SpFN-ALFQ vaccination protected against SARS-CoV-2-induced disease and viral replication following intranasal B.1.1.7 or B.1.351 challenge, as evidenced by reduced weight loss, lung pathology, and lung and nasal turbinate viral burden. These data support the development of SpFN-ALFQ as a broadly protective, next-generation SARS-CoV-2 vaccine.
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The need for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) next-generation vaccines has been highlighted by the rise of variants of concern (VoCs) and the long-term threat of emerging coronaviruses. Here, we design and characterize four categories of engineered nanoparticle immunogens that recapitulate the structural and antigenic properties of the prefusion SARS-CoV-2 spike (S), S1, and receptor-binding domain (RBD). These immunogens induce robust S binding, ACE2 inhibition, and authentic and pseudovirus neutralizing antibodies against SARS-CoV-2. A spike-ferritin nanoparticle (SpFN) vaccine elicits neutralizing titers (ID50 > 10,000) following a single immunization, whereas RBD-ferritin nanoparticle (RFN) immunogens elicit similar responses after two immunizations and also show durable and potent neutralization against circulating VoCs. Passive transfer of immunoglobulin G (IgG) purified from SpFN- or RFN-immunized mice protects K18-hACE2 transgenic mice from a lethal SARS-CoV-2 challenge. Furthermore, S-domain nanoparticle immunization elicits ACE2-blocking activity and ID50 neutralizing antibody titers >2,000 against SARS-CoV-1, highlighting the broad response elicited by these immunogens.
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The emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants stresses the continued need for next-generation vaccines that confer broad protection against coronavirus disease 2019 (COVID-19). We developed and evaluated an adjuvanted SARS-CoV-2 Spike Ferritin Nanoparticle (SpFN) vaccine in nonhuman primates (NHPs). High-dose (50 µ g) SpFN vaccine, given twice within a 28 day interval, induced a Th1-biased CD4 T cell helper response and a peak neutralizing antibody geometric mean titer of 52,773 against wild-type virus, with activity against SARS-CoV-1 and minimal decrement against variants of concern. Vaccinated animals mounted an anamnestic response upon high-dose SARS-CoV-2 respiratory challenge that translated into rapid elimination of replicating virus in their upper and lower airways and lung parenchyma. SpFN's potent and broad immunogenicity profile and resulting efficacy in NHPs supports its utility as a candidate platform for SARS-like betacoronaviruses. ONE-SENTENCE SUMMARY: A SARS-CoV-2 Spike protein ferritin nanoparticle vaccine, co-formulated with a liposomal adjuvant, elicits broad neutralizing antibody responses that exceed those observed for other major vaccines and rapidly protects against respiratory infection and disease in the upper and lower airways and lung tissue of nonhuman primates.