Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 797
Filtrar
Adicionar filtros

Base de dados
Tipo de documento
Ano de publicação
Intervalo de ano
1.
Ann Intern Med ; 174(8): 1073-1080, 2021 08.
Artigo em Inglês | MEDLINE | ID: covidwho-1456490

RESUMO

BACKGROUND: Assessing the evolution of SARS-CoV-2 immune response among patients receiving dialysis can define its durability in a highly clinically relevant context because patients receiving dialysis share the characteristics of persons most susceptible to SARS-CoV-2 infection. OBJECTIVE: To evaluate the persistence of SARS-CoV-2 receptor-binding domain (RBD) IgG in seroprevalent patients receiving dialysis. DESIGN: Prospective. SETTING: Nationwide sample from dialysis facilities. PATIENTS: 2215 patients receiving dialysis who had evidence of SARS-CoV-2 infection as of July 2020. MEASUREMENTS: Remainder plasma from routine monthly laboratories was used to measure semiquantitative RBD IgG index value over 6 months. RESULTS: A total of 2063 (93%) seroprevalent patients reached an assay detectable response (IgG index value ≥1). Most (n = 1323, 60%) had responses in July with index values classified as high (IgG ≥10); 1003 (76%) remained within this stratum. Adjusted median index values declined slowly but continuously (July vs. December values were 21 vs. 13; P < 0.001). The trajectory of the response did not vary by age group, sex, race/ethnicity, or diabetes status. Patients without an assay detectable response (n = 137) were more likely to be White and in the younger (18 to 44 years) or older (≥80 years) age groups and less likely to have diabetes and hypoalbuminemia. LIMITATION: Lack of data on symptoms or reverse transcriptase polymerase chain reaction diagnosis, cohort of persons who survived infection, and use of a semiquantitative assay. CONCLUSION: Despite impaired immunity, most seropositive patients receiving dialysis maintained RBD antibody levels over 6 months. A slow and continual decline in median antibody levels over time was seen, but no indication that subgroups with impaired immunity had a shorter-lived humoral response was found. PRIMARY FUNDING SOURCE: Ascend Clinical Laboratories.


Assuntos
Anticorpos Antivirais/sangue , COVID-19/imunologia , Imunoglobulina G/sangue , Domínios Proteicos/imunologia , Diálise Renal , Glicoproteína da Espícula de Coronavírus/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/imunologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , SARS-CoV-2 , Adulto Jovem
2.
BMC Med ; 19(1): 208, 2021 08 23.
Artigo em Inglês | MEDLINE | ID: covidwho-1455966

RESUMO

BACKGROUND: Coronavirus SARS-CoV-2, the causative agent of COVID-19, has caused a still evolving global pandemic. Given the worldwide vaccination campaign, the understanding of the vaccine-induced versus COVID-19-induced immunity will contribute to adjusting vaccine dosing strategies and speeding-up vaccination efforts. METHODS: Anti-spike-RBD IgGs and neutralizing antibodies (NAbs) titers were measured in BNT162b2 mRNA vaccinated participants (n = 250); we also investigated humoral and cellular immune responses in vaccinated individuals (n = 21) of this cohort 5 months post-vaccination and assayed NAbs levels in COVID-19 hospitalized patients (n = 60) with moderate or severe disease, as well as in COVID-19 recovered patients (n = 34). RESULTS: We found that one (boosting) dose of the BNT162b2 vaccine triggers robust immune (i.e., anti-spike-RBD IgGs and NAbs) responses in COVID-19 convalescent healthy recipients, while naïve recipients require both priming and boosting shots to acquire high antibody titers. Severe COVID-19 triggers an earlier and more intense (versus moderate disease) immune response in hospitalized patients; in all cases, however, antibody titers remain at high levels in COVID-19 recovered patients. Although virus infection promotes an earlier and more intense, versus priming vaccination, immune response, boosting vaccination induces antibody titers significantly higher and likely more durable versus COVID-19. In support, high anti-spike-RBD IgGs/NAbs titers along with spike (vaccine encoded antigen) specific T cell clones were found in the serum and peripheral blood mononuclear cells, respectively, of vaccinated individuals 5 months post-vaccination. CONCLUSIONS: These findings support vaccination efficacy, also suggesting that vaccination likely offers more protection than natural infection.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/uso terapêutico , COVID-19 , Glicoproteína da Espícula de Coronavírus/imunologia , COVID-19/prevenção & controle , COVID-19/terapia , Humanos , Cinética , Leucócitos Mononucleares , RNA Mensageiro , SARS-CoV-2
3.
Front Immunol ; 12: 739037, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1448729

RESUMO

Background: Transfusion of COVID-19 convalescent plasma (CCP) containing high titers of anti-SARS-CoV-2 antibodies serves as therapy for COVID-19 patients. Transfusions early during disease course was found to be beneficial. Lessons from the SARS-CoV-2 pandemic could inform early responses to future pandemics and may continue to be relevant in lower resource settings. We sought to identify factors correlating to high antibody titers in convalescent plasma donors and understand the magnitude and pharmacokinetic time course of both transfused antibody titers and the endogenous antibody titers in transfused recipients. Methods: Plasma samples were collected up to 174 days after convalescence from 93 CCP donors with mild disease, and from 16 COVID-19 patients before and after transfusion. Using ELISA, anti-SARS-CoV-2 Spike RBD, S1, and N-protein antibodies, as well as capacity of antibodies to block ACE2 from binding to RBD was measured in an in vitro assay. As an estimate for viral load, viral RNA and N-protein plasma levels were assessed in COVID-19 patients. Results: Anti-SARS-CoV-2 antibody levels and RBD-ACE2 blocking capacity were highest within the first 60 days after symptom resolution and markedly decreased after 120 days. Highest antibody titers were found in CCP donors that experienced fever. Effect of transfused CCP was detectable in COVID-19 patients who received high-titer CCP and had not seroconverted at the time of transfusion. Decrease in viral RNA was seen in two of these patients. Conclusion: Our results suggest that high titer CCP should be collected within 60 days after recovery from donors with past fever. The much lower titers conferred by transfused antibodies compared to endogenous production in the patient underscore the importance of providing CCP prior to endogenous seroconversion.


Assuntos
COVID-19/terapia , Convalescença , SARS-CoV-2/imunologia , Soroconversão , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Antígenos Virais/sangue , Doadores de Sangue , COVID-19/sangue , COVID-19/imunologia , Feminino , Humanos , Imunização Passiva , Cinética , Masculino , Pessoa de Meia-Idade , Pacientes Ambulatoriais , RNA Viral/sangue
4.
Immunol Invest ; 50(7): 743-779, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: covidwho-1447461

RESUMO

COVID-19, the disease caused by the novel severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), was first detected in December 2019 and has since morphed into a global pandemic claiming over 2.4 million human lives and severely impacting global economy. The race for a safe and efficacious vaccine was thus initiated with government agencies as well as major pharmaceutical companies as frontrunners. An ideal vaccine would activate multiple arms of the adaptive immune system to generate cytotoxic T cell responses as well as neutralizing antibody responses, while avoiding pathological or deleterious immune responses that result in tissue damage or exacerbation of the disease. Developing an effective vaccine requires an inter-disciplinary effort involving virology, protein biology, biotechnology, immunology and pharmaceutical sciences. In this review, we provide a brief overview of the pathology and immune responses to SARS-CoV-2, which are fundamental to vaccine development. We then summarize the rationale for developing COVID-19 vaccines and provide novel insights into vaccine development from a pharmaceutical science perspective, such as selection of different antigens, adjuvants, delivery platforms and formulations. Finally, we review multiple clinical trial outcomes of novel vaccines in terms of safety and efficacy.


Assuntos
Vacinas contra COVID-19/imunologia , COVID-19/imunologia , Anticorpos Neutralizantes/imunologia , Ensaios Clínicos como Assunto , Humanos , Pandemias/prevenção & controle , SARS-CoV-2/imunologia
5.
Nature ; 597(7878): 703-708, 2021 09.
Artigo em Inglês | MEDLINE | ID: covidwho-1442788

RESUMO

SARS-CoV-2 infections have surged across the globe in recent months, concomitant with considerable viral evolution1-3. Extensive mutations in the spike protein may threaten the efficacy of vaccines and therapeutic monoclonal antibodies4. Two signature spike mutations of concern are E484K, which has a crucial role in the loss of neutralizing activity of antibodies, and N501Y, a driver of rapid worldwide transmission of the B.1.1.7 lineage. Here we report the emergence of the variant lineage B.1.526 (also known as the Iota variant5), which contains E484K, and its rise to dominance in New York City in early 2021. This variant is partially or completely resistant to two therapeutic monoclonal antibodies that are in clinical use and is less susceptible to neutralization by plasma from individuals who had recovered from SARS-CoV-2 infection or serum from vaccinated individuals, posing a modest antigenic challenge. The presence of the B.1.526 lineage has now been reported in all 50 states in the United States and in many other countries. B.1.526 rapidly replaced earlier lineages in New York, with an estimated transmission advantage of 35%. These transmission dynamics, together with the relative antibody resistance of its E484K sub-lineage, are likely to have contributed to the sharp rise and rapid spread of B.1.526. Although SARS-CoV-2 B.1.526 initially outpaced B.1.1.7 in the region, its growth subsequently slowed concurrently with the rise of B.1.1.7 and ensuing variants.


Assuntos
COVID-19/virologia , SARS-CoV-2/crescimento & desenvolvimento , SARS-CoV-2/isolamento & purificação , Anticorpos Neutralizantes/imunologia , Humanos , Mutação , New York/epidemiologia , Filogenia , Filogeografia , Prevalência , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Estados Unidos/epidemiologia
6.
Signal Transduct Target Ther ; 6(1): 346, 2021 09 24.
Artigo em Inglês | MEDLINE | ID: covidwho-1437668

RESUMO

Antibody-dependent cellular cytotoxicity (ADCC) responses to viral infection are a form of antibody regulated immune responses mediated through the Fc fragment. Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) triggered ADCC responses contributes to COVID-19 disease development is currently not well understood. To understand the potential correlation between ADCC responses and COVID-19 disease development, we analyzed the ADCC activity and neutralizing antibody response in 255 individuals ranging from asymptomatic to fatal infections over 1 year post disease. ADCC was elicited by 10 days post-infection, peaked by 11-20 days, and remained detectable until 400 days post-infection. In general, patients with severe disease had higher ADCC activities. Notably, patients who had severe disease and recovered had higher ADCC activities than patients who had severe disease and deceased. Importantly, ADCC activities were mediated by a diversity of epitopes in SARS-COV-2-infected mice and induced to comparable levels against SARS-CoV-2 variants of concern (VOCs) (B.1.1.7, B.1.351, and P.1) as that against the D614G mutant in human patients and vaccinated mice. Our study indicates anti-SARS-CoV-2 ADCC as a major trait of COVID-19 patients with various conditions, which can be applied to estimate the extra-neutralization level against COVID-19, especially lethal COVID-19.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Citotoxicidade Celular Dependente de Anticorpos , COVID-19/imunologia , SARS-CoV-2/imunologia , Adulto , Idoso , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade
7.
Sci Immunol ; 6(62)2021 08 19.
Artigo em Inglês | MEDLINE | ID: covidwho-1434875

RESUMO

Circulating autoantibodies (auto-Abs) neutralizing high concentrations (10 ng/mL, in plasma diluted 1 to 10) of IFN-α and/or -ω are found in about 10% of patients with critical COVID-19 pneumonia, but not in subjects with asymptomatic infections. We detect auto-Abs neutralizing 100-fold lower, more physiological, concentrations of IFN-α and/or -ω (100 pg/mL, in 1/10 dilutions of plasma) in 13.6% of 3,595 patients with critical COVID-19, including 21% of 374 patients > 80 years, and 6.5% of 522 patients with severe COVID-19. These antibodies are also detected in 18% of the 1,124 deceased patients (aged 20 days-99 years; mean: 70 years). Moreover, another 1.3% of patients with critical COVID-19 and 0.9% of the deceased patients have auto-Abs neutralizing high concentrations of IFN-ß. We also show, in a sample of 34,159 uninfected subjects from the general population, that auto-Abs neutralizing high concentrations of IFN-α and/or -ω are present in 0.18% of individuals between 18 and 69 years, 1.1% between 70 and 79 years, and 3.4% >80 years. Moreover, the proportion of subjects carrying auto-Abs neutralizing lower concentrations is greater in a subsample of 10,778 uninfected individuals: 1% of individuals <70 years, 2.3% between 70 and 80 years, and 6.3% >80 years. By contrast, auto-Abs neutralizing IFN-ß do not become more frequent with age. Auto-Abs neutralizing type I IFNs predate SARS-CoV-2 infection and sharply increase in prevalence after the age of 70 years. They account for about 20% of both critical COVID-19 cases in the over-80s, and total fatal COVID-19 cases.


Assuntos
Autoanticorpos/imunologia , COVID-19/imunologia , Interferon Tipo I/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Autoanticorpos/sangue , COVID-19/mortalidade , Estudos de Casos e Controles , Criança , Pré-Escolar , Estado Terminal , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lactente , Recém-Nascido , Interferon-alfa/imunologia , Pessoa de Meia-Idade , Adulto Jovem
8.
Nat Microbiol ; 6(10): 1233-1244, 2021 10.
Artigo em Inglês | MEDLINE | ID: covidwho-1434113

RESUMO

Understanding the molecular basis for immune recognition of SARS-CoV-2 spike glycoprotein antigenic sites will inform the development of improved therapeutics. We determined the structures of two human monoclonal antibodies-AZD8895 and AZD1061-which form the basis of the investigational antibody cocktail AZD7442, in complex with the receptor-binding domain (RBD) of SARS-CoV-2 to define the genetic and structural basis of neutralization. AZD8895 forms an 'aromatic cage' at the heavy/light chain interface using germ line-encoded residues in complementarity-determining regions (CDRs) 2 and 3 of the heavy chain and CDRs 1 and 3 of the light chain. These structural features explain why highly similar antibodies (public clonotypes) have been isolated from multiple individuals. AZD1061 has an unusually long LCDR1; the HCDR3 makes interactions with the opposite face of the RBD from that of AZD8895. Using deep mutational scanning and neutralization escape selection experiments, we comprehensively mapped the crucial binding residues of both antibodies and identified positions of concern with regards to virus escape from antibody-mediated neutralization. Both AZD8895 and AZD1061 have strong neutralizing activity against SARS-CoV-2 and variants of concern with antigenic substitutions in the RBD. We conclude that germ line-encoded antibody features enable recognition of the SARS-CoV-2 spike RBD and demonstrate the utility of the cocktail AZD7442 in neutralizing emerging variant viruses.


Assuntos
Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , SARS-CoV-2/imunologia , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Variação Antigênica , Sítios de Ligação , COVID-19/imunologia , COVID-19/virologia , Regiões Determinantes de Complementaridade/química , Regiões Determinantes de Complementaridade/genética , Humanos , Mutação , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia
9.
Nat Commun ; 12(1): 5469, 2021 09 22.
Artigo em Inglês | MEDLINE | ID: covidwho-1434103

RESUMO

SARS-CoV-2 remains a global threat to human health particularly as escape mutants emerge. There is an unmet need for effective treatments against COVID-19 for which neutralizing single domain antibodies (nanobodies) have significant potential. Their small size and stability mean that nanobodies are compatible with respiratory administration. We report four nanobodies (C5, H3, C1, F2) engineered as homotrimers with pmolar affinity for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Crystal structures show C5 and H3 overlap the ACE2 epitope, whilst C1 and F2 bind to a different epitope. Cryo Electron Microscopy shows C5 binding results in an all down arrangement of the Spike protein. C1, H3 and C5 all neutralize the Victoria strain, and the highly transmissible Alpha (B.1.1.7 first identified in Kent, UK) strain and C1 also neutralizes the Beta (B.1.35, first identified in South Africa). Administration of C5-trimer via the respiratory route showed potent therapeutic efficacy in the Syrian hamster model of COVID-19 and separately, effective prophylaxis. The molecule was similarly potent by intraperitoneal injection.


Assuntos
Anticorpos Neutralizantes/farmacologia , COVID-19/tratamento farmacológico , Anticorpos de Domínio Único/farmacologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Administração Intranasal , Animais , Anticorpos Neutralizantes/administração & dosagem , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/imunologia , Microscopia Crioeletrônica , Cristalografia por Raios X , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Epitopos/química , Epitopos/metabolismo , Feminino , Masculino , Mesocricetus , Testes de Neutralização , SARS-CoV-2/efeitos dos fármacos , Anticorpos de Domínio Único/administração & dosagem , Anticorpos de Domínio Único/imunologia , Anticorpos de Domínio Único/metabolismo , Glicoproteína da Espícula de Coronavírus/química
10.
Front Immunol ; 12: 737083, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1430703

RESUMO

mRNA-based vaccines effectively induce protective neutralizing antibodies against SARS-CoV-2, the etiological agent of COVID-19. Yet, the kinetics and compositional patterns of vaccine-induced antibody responses to the original strain and emerging variants of concern remain largely unknown. Here we characterized serum antibody classes and subclasses targeting the spike receptor-binding domain of SARS-CoV-2 wild type and α, ß, γ and δ variants in a longitudinal cohort of SARS-CoV-2 naïve and COVID-19 recovered individuals receiving the mRNA-1273 vaccine. We found that mRNA-1273 vaccine recipients developed a SARS-CoV-2-specific antibody response with a subclass profile comparable to that induced by natural infection. Importantly, these antibody responses targeted both wild type SARS-CoV-2 as well as its α, ß, γ and δ variants. Following primary vaccination, individuals with pre-existing immunity showed higher induction of all antibodies but IgG3 compared to SARS-CoV-2-naïve subjects. Unlike naïve individuals, COVID-19 recovered subjects did not mount a recall antibody response upon the second vaccine dose. In these individuals, secondary immunization resulted in a slight reduction of IgG1 against the receptor-binding domain of ß and γ variants. Despite the lack of recall humoral response, vaccinees with pre-existing immunity still showed higher titers of IgG1 and IgA to all variants analyzed compared to fully vaccinated naïve individuals. Our findings indicate that mRNA-1273 vaccine triggered cross-variant antibody responses with distinct profiles in vaccinees with or without pre-existing immunity and suggest that individuals with prior history of SARS-CoV-2 infection may not benefit from the second mRNA vaccine dose with the current standard regimen.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Vacinas contra COVID-19/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , COVID-19/prevenção & controle , Convalescença , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Estudos Longitudinais , Masculino , Espanha , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinação
11.
Front Immunol ; 12: 724060, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1430701

RESUMO

Thirty-five peptides selected from functionally-relevant SARS-CoV-2 spike (S), membrane (M), and envelope (E) proteins were suitably modified for immunising MHC class II (MHCII) DNA-genotyped Aotus monkeys and matched with HLA-DRß1* molecules for use in humans. This was aimed at producing the first minimal subunit-based, chemically-synthesised, immunogenic molecules (COLSARSPROT) covering several HLA alleles. They were predicted to cover 48.25% of the world's population for 6 weeks (short-term) and 33.65% for 15 weeks (long-lasting) as they induced very high immunofluorescent antibody (IFA) and ELISA titres against S, M and E parental native peptides, SARS-CoV-2 neutralising antibodies and host cell infection. The same immunological methods that led to identifying new peptides for inclusion in the COLSARSPROT mixture were used for antigenicity studies. Peptides were analysed with serum samples from patients suffering mild or severe SARS-CoV-2 infection, thereby increasing chemically-synthesised peptides' potential coverage for the world populations up to 62.9%. These peptides' 3D structural analysis (by 1H-NMR acquired at 600 to 900 MHz) suggested structural-functional immunological association. This first multi-protein, multi-epitope, minimal subunit-based, chemically-synthesised, highly immunogenic peptide mixture highlights such chemical synthesis methodology's potential for rapidly obtaining very pure, highly reproducible, stable, cheap, easily-modifiable peptides for inducing immune protection against COVID-19, covering a substantial percentage of the human population.


Assuntos
Vacinas contra COVID-19/imunologia , COVID-19/imunologia , Proteínas do Envelope de Coronavírus/imunologia , Proteínas M de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas de Subunidades/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Aotidae , COVID-19/prevenção & controle , Cadeias HLA-DRB1/genética , Humanos , Peptídeos/imunologia , SARS-CoV-2/imunologia
12.
Front Immunol ; 12: 715464, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1430698

RESUMO

The mutants resulted from the ongoing SARS-CoV-2 epidemic have showed resistance to antibody neutralization and vaccine-induced immune response. The present study isolated and identified two novel SARS-CoV-2 neutralizing antibodies (nAbs) from convalescent COVID-19 patients. These two nAbs (XG81 and XG83) were then systemically compared with nine nAbs that were reconstructed by using published data, and revealed that, even though these two nAbs shared targeting epitopes on spike protein, they were different from any of the nine nAbs. Compared with XG81, XG83 exhibited a higher RBD binding affinity and neutralization potency against wild-typed pseudovirus, variant pseudoviruses with mutated spike proteins, such as D614G, E484Q, and A475V, as well as the authentic SARS-CoV-2 virus. To explore potential broadly neutralizing antibodies, heavy and light chains from all 18 nAbs (16 published nAbs, XG81 and XG83) were cross-recombined, and some of the functional antibodies were screened and studied for RBD binding affinity, and neutralizing activity against pseudovirus and the authentic SARS-CoV-2 virus. The results demonstrated that several recombined antibodies had a more potent neutralization activity against variant pseudoviruses compared with the originally paired Abs. Taken together, the novel neutralizing antibodies identified in this study are a likely valuable addition to candidate antibody drugs for the development of clinical therapeutic agents against SARS-CoV-2 to minimize mutational escape.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Amplamente Neutralizantes/imunologia , Anticorpos Amplamente Neutralizantes/uso terapêutico , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/genética , Anticorpos Antivirais/uso terapêutico , Afinidade de Anticorpos/imunologia , Linfócitos B/imunologia , Anticorpos Amplamente Neutralizantes/genética , COVID-19/imunologia , COVID-19/terapia , Linhagem Celular , Epitopos/imunologia , Humanos , Imunoterapia/métodos , Testes de Neutralização , SARS-CoV-2/efeitos dos fármacos
13.
Front Immunol ; 12: 701411, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1430694

RESUMO

In March 2020, the World Health Organization (WHO) declared a global health emergency-the coronavirus disease 2019 (COVID-19) pandemic. Since then, the development and implementation of vaccines against the virus amidst emerging cases of re-infection has prompted researchers to work towards understanding how immunity develops and is sustained. Serological testing has been instrumental in monitoring the development and persistence of antibodies against SARS-CoV-2 infection, however inconsistencies in detection have been reported by different methods. As serological testing becomes more commonplace, it is important to establish widespread and repeatable processes for monitoring vaccine efficacy. Therefore, we present enzyme linked immunosorbent assays (ELISAs) compatible for antibody detection in saliva as highly accurate, efficacious, and scalable tools for studying the immune response in individuals vaccinated against SARS-CoV-2.


Assuntos
Anticorpos Neutralizantes/análise , Anticorpos Antivirais/análise , COVID-19/imunologia , SARS-CoV-2/imunologia , Saliva/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , Ensaio de Imunoadsorção Enzimática , Humanos
15.
J Infect Dis ; 224(6): 989-994, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: covidwho-1429251

RESUMO

The SARS-CoV-2 B.1.617 variant emerged in the Indian state of Maharashtra in late 2020. There have been fears that 2 key mutations seen in the receptor-binding domain, L452R and E484Q, would have additive effects on evasion of neutralizing antibodies. We report that spike bearing L452R and E484Q confers modestly reduced sensitivity to BNT162b2 mRNA vaccine-elicited antibodies following either first or second dose. The effect is similar in magnitude to the loss of sensitivity conferred by L452R or E484Q alone. These data demonstrate reduced sensitivity to vaccine-elicited neutralizing antibodies by L452R and E484Q but lack of synergistic loss of sensitivity.


Assuntos
COVID-19/imunologia , COVID-19/virologia , Evasão da Resposta Imune , Mutação , SARS-CoV-2/genética , Enzima de Conversão de Angiotensina 2 , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Vacinas contra COVID-19/imunologia , Chlorocebus aethiops , Células HEK293 , Humanos , Índia , Ligação Proteica , SARS-CoV-2/imunologia , Serina Endopeptidases , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Células Vero
16.
Emerg Microbes Infect ; 10(1): 1931-1946, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: covidwho-1429140

RESUMO

Identification of relevant epitopes is crucial for the development of subunit peptide vaccines inducing neutralizing and cellular immunity against SARS-CoV-2. Our aim was the characterization of epitopes in the receptor-binding domain (RBD) of SARS-CoV-2 spike (S) protein to generate a peptide vaccine. Epitope mapping using a panel of 10 amino acid overlapped 15-mer peptides covering region 401-515 from RBD did not identify linear epitopes when tested with sera from infected individuals or from RBD-immunized mice. However, immunization of mice with these 15-mer peptides identified four peptides located at region 446-480 that induced antibodies recognizing the peptides and RBD/S1 proteins. Immunization with peptide 446-480 from S protein formulated with Freund's adjuvant or with CpG oligodeoxinucleotide/Alum induced polyepitopic antibody responses in BALB/c and C56BL/6J mice, recognizing RBD (titres of 3 × 104-3 × 105, depending on the adjuvant) and displaying neutralizing capacity (80-95% inhibition capacity; p < 0.05) against SARS-CoV-2. Murine CD4 and CD8T-cell epitopes were identified in region 446-480 and vaccination experiments using HLA transgenic mice suggested the presence of multiple human T-cell epitopes. Antibodies induced by peptide 446-480 showed broad recognition of S proteins and S-derived peptides belonging to SARS-CoV-2 variants of concern. Importantly, vaccination with peptide 446-480 or with a cyclic version of peptide 446-488 containing a disulphide bridge between cysteines 480 and 488, protected humanized K18-hACE2 mice from a lethal dose of SARS-CoV-2 (62.5 and 75% of protection; p < 0.01 and p < 0.001, respectively). This region could be the basis for a peptide vaccine or other vaccine platforms against Covid-19.


Assuntos
Anticorpos Neutralizantes/imunologia , Vacinas contra COVID-19/imunologia , COVID-19/prevenção & controle , Imunidade Celular , Imunidade Humoral , SARS-CoV-2/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Neutralizantes/sangue , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , COVID-19/imunologia , Vacinas contra COVID-19/normas , Reações Cruzadas/imunologia , Mapeamento de Epitopos , Epitopos de Linfócito B , Epitopos de Linfócito T/imunologia , Humanos , Imunização , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas de Subunidades/imunologia , Vacinas Sintéticas/imunologia
17.
Nat Commun ; 12(1): 5506, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: covidwho-1428815

RESUMO

Antibody engineering technologies face increasing demands for speed, reliability and scale. We develop CeVICA, a cell-free nanobody engineering platform that uses ribosome display for in vitro selection of nanobodies from a library of 1011 randomized sequences. We apply CeVICA to engineer nanobodies against the Receptor Binding Domain (RBD) of SARS-CoV-2 spike protein and identify >800 binder families using a computational pipeline based on CDR-directed clustering. Among 38 experimentally-tested families, 30 are true RBD binders and 11 inhibit SARS-CoV-2 pseudotyped virus infection. Affinity maturation and multivalency engineering increase nanobody binding affinity and yield a virus neutralizer with picomolar IC50. Furthermore, the capability of CeVICA for comprehensive binder prediction allows us to validate the fitness of our nanobody library. CeVICA offers an integrated solution for rapid generation of divergent synthetic nanobodies with tunable affinities in vitro and may serve as the basis for automated and highly parallel nanobody engineering.


Assuntos
Anticorpos Neutralizantes/imunologia , Engenharia de Proteínas , SARS-CoV-2/efeitos dos fármacos , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/farmacologia , Anticorpos Antivirais , COVID-19/tratamento farmacológico , Humanos , Ligação Proteica , Reprodutibilidade dos Testes , Anticorpos de Domínio Único/genética , Glicoproteína da Espícula de Coronavírus
18.
PLoS Pathog ; 17(9): e1009804, 2021 09.
Artigo em Inglês | MEDLINE | ID: covidwho-1416909

RESUMO

Prior studies have demonstrated that immunologic dysfunction underpins severe illness in COVID-19 patients, but have lacked an in-depth analysis of the immunologic drivers of death in the most critically ill patients. We performed immunophenotyping of viral antigen-specific and unconventional T cell responses, neutralizing antibodies, and serum proteins in critically ill patients with SARS-CoV-2 infection, using influenza infection, SARS-CoV-2-convalescent health care workers, and healthy adults as controls. We identify mucosal-associated invariant T (MAIT) cell activation as an independent and significant predictor of death in COVID-19 (HR = 5.92, 95% CI = 2.49-14.1). MAIT cell activation correlates with several other mortality-associated immunologic measures including broad activation of CD8+ T cells and non-Vδ2 γδT cells, and elevated levels of cytokines and chemokines, including GM-CSF, CXCL10, CCL2, and IL-6. MAIT cell activation is also a predictor of disease severity in influenza (ECMO/death HR = 4.43, 95% CI = 1.08-18.2). Single-cell RNA-sequencing reveals a shift from focused IFNα-driven signals in COVID-19 ICU patients who survive to broad pro-inflammatory responses in fatal COVID-19 -a feature not observed in severe influenza. We conclude that fatal COVID-19 infection is driven by uncoordinated inflammatory responses that drive a hierarchy of T cell activation, elements of which can serve as prognostic indicators and potential targets for immune intervention.


Assuntos
COVID-19/imunologia , COVID-19/mortalidade , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos CD/imunologia , Antígenos de Diferenciação de Linfócitos T/imunologia , Linfócitos B/imunologia , Biomarcadores/sangue , Proteínas Sanguíneas/metabolismo , Estudos de Coortes , Estado Terminal/mortalidade , Feminino , Humanos , Imunofenotipagem , Influenza Humana/imunologia , Lectinas Tipo C/imunologia , Ativação Linfocitária , Masculino , Pessoa de Meia-Idade , Células T Invariantes Associadas à Mucosa/imunologia , Gravidade do Paciente
19.
J Infect Dis ; 224(5): 764-770, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: covidwho-1413436

RESUMO

The kinetics of immunoglobulin G (IgG) avidity maturation during severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection obtained from 217 participants of the Ischgl cohort, Austria, was studied 0.5-1.5 months (baseline) and 7-8 months (follow-up) after infection. The IgG avidity assay, using a modified IgG enzyme-linked immunosorbent assay (ELISA) and 5.5 M urea, revealed that old age does not diminish the increase in avidity, detected in all participants positive at both time points, from 18% to 42%. High avidity was associated with a marked residual neutralization capacity in 97.2.% of participants (211/217), which was even higher in the older age group, revealing an important role of avidity assays as easy and cheap surrogate tests for assessing the maturation of the immune system conveying potential protection against further SARS-CoV-2 infections without necessitating expensive and laborious neutralization assays.


Assuntos
Anticorpos Antivirais/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Anticorpos Neutralizantes/imunologia , Áustria , Estudos de Coortes , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
PLoS One ; 16(9): e0257191, 2021.
Artigo em Inglês | MEDLINE | ID: covidwho-1412845

RESUMO

COVID-19 in humans is caused by Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) that belongs to the beta family of coronaviruses. SARS-CoV-2 causes severe respiratory illness in 10-15% of infected individuals and mortality in 2-3%. Vaccines are urgently needed to prevent infection and to contain viral spread. Although several mRNA- and adenovirus-based vaccines are highly effective, their dependence on the "cold chain" transportation makes global vaccination a difficult task. In this context, a stable lyophilized vaccine may present certain advantages. Accordingly, establishing additional vaccine platforms remains vital to tackle SARS-CoV-2 and any future variants that may arise. Vaccinia virus (VACV) has been used to eradicate smallpox disease, and several attenuated viral strains with enhanced safety for human applications have been developed. We have generated two candidate SARS-CoV-2 vaccines based on two vaccinia viral strains, MVA and v-NY, that express full-length SARS-CoV-2 spike protein. Whereas MVA is growth-restricted in mammalian cells, the v-NY strain is replication-competent. We demonstrate that both candidate recombinant vaccines induce high titers of neutralizing antibodies in C57BL/6 mice vaccinated according to prime-boost regimens. Furthermore, our vaccination regimens generated TH1-biased immune responses in mice. Most importantly, prime-boost vaccination of a Syrian hamster infection model with MVA-S and v-NY-S protected the hamsters against SARS-CoV-2 infection, supporting that these two vaccines are promising candidates for future development. Finally, our vaccination regimens generated neutralizing antibodies that partially cross-neutralized SARS-CoV-2 variants of concern.


Assuntos
Vacinas contra COVID-19/administração & dosagem , COVID-19/imunologia , Vírus Vaccinia/genética , Animais , Anticorpos Neutralizantes/análise , Anticorpos Neutralizantes/imunologia , COVID-19/virologia , Vacinas contra COVID-19/genética , Feminino , Imunização Secundária , Pulmão/patologia , Masculino , Mesocricetus , Camundongos , Camundongos Endogâmicos C57BL , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...