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IntroductionAntibody therapeutic strategies have served an important role during the COVID-19 pandemic, even as their effectiveness has waned with the emergence of escape variants. Here we sought to determine the concentration of convalescent immunoglobulin required to protect against disease from SARS-CoV-2 in a Syrian golden hamster model.MethodsTotal IgG and IgM were isolated from plasma of SARS-CoV-2 convalescent donors. Dose titrations of IgG and IgM were infused into hamsters 1 day prior to challenge with SARS-CoV-2 Wuhan-1.ResultsThe IgM preparation was found to have ~25-fold greater neutralization potency than IgG. IgG infusion protected hamsters from disease in a dose-dependent manner, with detectable serum neutralizing titers correlating with protection. Despite a higher in vitro neutralizing potency, IgM failed to protect against disease when transferred into hamsters.DiscussionThis study adds to the growing body of literature that demonstrates neutralizing IgG antibodies are important for protection from SARS-CoV-2 disease, and confirms that polyclonal IgG in sera can be an effective preventative strategy if the neutralizing titers are sufficiently high. In the context of new variants, against which existing vaccines or monoclonal antibodies have reduced efficacy, sera from individuals who have recovered from infection with the emerging variant may potentially remain an efficacious tool.

Abstract SARS-CoV-2 Spike-specific binding and neutralizing antibodies, elicited either by natural infection or vaccination, have emerged as potential correlates of protection. An important question, however, is whether vaccine-elicited antibodies in humans provide direct, functional protection from SARS-CoV-2 infection and disease. In this study, we explored directly the protective efficacy of human antibodies elicited by Ad26.COV2.S vaccination by adoptive transfer studies. IgG from plasma of Ad26.COV2.S vaccinated individuals was purified and transferred into naïve golden Syrian hamster recipients, followed by intra-nasal challenge of the hamsters with SARS-CoV-2. IgG purified from Ad26.COV2.S-vaccinated individuals provided dose-dependent protection in the recipient hamsters from weight loss following challenge. In contrast, IgG purified from placebo recipients provided no protection in this adoptive transfer model. Attenuation of weight loss correlated with binding and neutralizing antibody titers of the passively transferred IgG. This study suggests that Ad26.COV2.S-elicited antibodies in humans are mechanistically involved in protection against SARS-CoV-2.

Abstract 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.

A COVID-19 vaccine that can give early protection is needed to eliminate the viral spread efficiently. Here, we demonstrate the development of a nanoparticle vaccine candidate, REVC-128, in which multiple trimeric spike ectodomains with glycine (G) at position 614 were multimerized onto a nanoparticle. In-vitro characterization of this vaccine confirms its structural and antigenic integrity. In-vivo immunogenicity evaluation in mice indicates that a single dose of this vaccine induces potent serum neutralizing antibody titre at two weeks post-immunization. This is significantly higher than titre caused by trimeric spike protein without nanoparticle presentation. The comparison of serum binding to spike subunits between animals immunized by a spike with and without nanoparticle presentation indicates that nanoparticle prefers the display of spike RBD (Receptor-Binding Domain) over S2 subunit, likely resulting in a more neutralizing but less cross-reactive antibody response. Moreover, a Syrian golden hamster in-vivo model for the SARS-CoV-2 virus challenge was implemented two weeks post a single dose of REVC-128 immunization. The results showed that vaccination protects hamsters against the SARS-CoV-2 virus challenge with evidence of steady body weight, suppressed viral loads and alleviation of tissue damage for protected animals, compared with ∼10% weight loss, high viral loads and tissue damage in unprotected animals. Furthermore, the data showed that vaccine REVC-128 is thermostable at up to 37°C for at least 4 weeks. These findings, along with a history of safety for protein vaccines, suggest that the REVC-128 is a safe, stable and efficacious single-shot vaccine to give the earliest protection against SARS-CoV-2 infection.

SARS-CoV-2 is the third pathogenic coronavirus to emerge since 2000. Experience from prior outbreaks of SARS-CoV and MERS-CoV has demonstrated the importance of both humoral and cellular immunity to clinical outcome, precepts that have been recapitulated for SARS-CoV-2. Despite the unprecedented rapid development and deployment of vaccines against SARS-CoV-2, more vaccines are needed to meet global demand and to guard against immune evasion by newly emerging SARS-CoV-2 variants. Here we describe the development of pGO-1002, a novel bi-cistronic synthetic DNA vaccine that encodes consensus sequences of two SARS-CoV-2 antigens, Spike and ORF3a. Mice immunized with pGO-1002 developed humoral and cellular responses to both antigens, including antibodies and capable of neutralizing infection by a clinical SARS-CoV-2 isolate. Rats immunized with pGO-1002 by intradermal (ID) injection followed by application of suction with our GeneDerm device also developed humoral responses that included neutralizing antibodies and RBD-ACE2 blocking antibodies as well as robust cellular responses to both antigens. Significantly, in a Syrian hamster vaccination and challenge model, ID+GeneDerm-assisted vaccination prevented viral replication in the lungs and significantly reduced viral replication in the nares of hamsters challenged with either an ancestral SARS-CoV-2 strain or the B.1.351 (Beta) variant of concern. Furthermore, vaccinated immune sera inhibited virus-mediated cytopathic effects in vitro. These data establish the immunogenicity of the SARS-CoV-2 vaccine candidate pGO-1002 which induces potent humoral and cellular responses to the Spike and ORF3a antigens and may provide greater protection against emerging variants.

Trata-se este trabalho de uma reflexão sobre as relações estabelecidas nos espaços de restrição de liberdade, a partir de observações no sistema prisional do Distrito Federal. Ali, homens e mulheres transformam suas regras, contrarregras, interditos e metáforas, criadas para, a partir de seu estar juntos, em estetizações produzidas para, de alguma maneira, territorializar seus lugares de convivência. Sustentando-se nos pressupostos da Etnocenologia para as noções de espetacularidade e teatralidade, este estudo privilegia os diálogos com os estudos da linguagem, nas analogias das Metáforas da vida Cotidiana, propostos por George Lakoff e Mark Johnson e com as formulações de territorialidades e não-lugares, de Marc Augé. Parte de anotações sobre comportamentos corporais e linguísticos de pessoas em conflito com a Lei, observados, prioritariamente em penitenciárias, onde um dos autores, como membro do corpo sócio-educativo, é professor de Artes Cênicas. Palavras-chaves Etnocenologia. Espetacularidade. Metáforas da Vida Cotidiana.

Trata-se este trabalho de uma reflexão sobre as relações estabelecidas nos espaços de restrição de liberdade, a partir de observações no sistema prisional do Distrito Federal. Ali, homens e mulheres transformam suas regras, contrarregras, interditos e metáforas, criadas para, a partir de seu estar juntos, em estetizações produzidas para, de alguma maneira, territorializar seus lugares de convivência. Sustentando-se nos pressupostos da Etnocenologia para as noções de espetacularidade e teatralidade, este estudo privilegia os diálogos com os estudos da linguagem, nas analogias das Metáforas da vida Cotidiana, propostos por George Lakoff e Mark Johnson e com as formulações de territorialidades e não-lugares, de Marc Augé. Parte de anotações sobre comportamentos corporais e linguísticos de pessoas em conflito com a Lei, observados, prioritariamente em penitenciárias, onde um dos autores, como membro do corpo sócio-educativo, é professor de Artes Cênicas. Palavras-chaves Etnocenologia. Espetacularidade. Metáforas da Vida Cotidiana.