Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 652
Filtrar
1.
Sci Transl Med ; 13(583)2021 03 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658355

RESUMO

Seasonal influenza vaccines confer protection against specific viral strains but have restricted breadth that limits their protective efficacy. The H1 and H3 subtypes of influenza A virus cause most of the seasonal epidemics observed in humans and are the major drivers of influenza A virus-associated mortality. The consequences of pandemic spread of COVID-19 underscore the public health importance of prospective vaccine development. Here, we show that headless hemagglutinin (HA) stabilized-stem immunogens presented on ferritin nanoparticles elicit broadly neutralizing antibody (bnAb) responses to diverse H1 and H3 viruses in nonhuman primates (NHPs) when delivered with a squalene-based oil-in-water emulsion adjuvant, AF03. The neutralization potency and breadth of antibodies isolated from NHPs were comparable to human bnAbs and extended to mismatched heterosubtypic influenza viruses. Although NHPs lack the immunoglobulin germline VH1-69 residues associated with the most prevalent human stem-directed bnAbs, other gene families compensated to generate bnAbs. Isolation and structural analyses of vaccine-induced bnAbs revealed extensive interaction with the fusion peptide on the HA stem, which is essential for viral entry. Antibodies elicited by these headless HA stabilized-stem vaccines neutralized diverse H1 and H3 influenza viruses and shared a mode of recognition analogous to human bnAbs, suggesting that these vaccines have the potential to confer broadly protective immunity against diverse viruses responsible for seasonal and pandemic influenza infections in humans.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vacinas contra Influenza/imunologia , Primatas/imunologia , Animais , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/química , Complexo Antígeno-Anticorpo/química , Anticorpos Amplamente Neutralizantes/biossíntese , Anticorpos Amplamente Neutralizantes/química , Ferritinas/química , Ferritinas/imunologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Humanos , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/química , Influenza Humana/imunologia , Influenza Humana/virologia , Macaca fascicularis , Modelos Moleculares , Nanopartículas/química , Pandemias , Primatas/virologia , Estrutura Quaternária de Proteína , Pesquisa Médica Translacional
2.
PLoS Pathog ; 17(3): e1009328, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33657135

RESUMO

A key step to the SARS-CoV-2 infection is the attachment of its Spike receptor-binding domain (S RBD) to the host receptor ACE2. Considerable research has been devoted to the development of neutralizing antibodies, including llama-derived single-chain nanobodies, to target the receptor-binding motif (RBM) and to block ACE2-RBD binding. Simple and effective strategies to increase potency are desirable for such studies when antibodies are only modestly effective. Here, we identify and characterize a high-affinity synthetic nanobody (sybody, SR31) as a fusion partner to improve the potency of RBM-antibodies. Crystallographic studies reveal that SR31 binds to RBD at a conserved and 'greasy' site distal to RBM. Although SR31 distorts RBD at the interface, it does not perturb the RBM conformation, hence displaying no neutralizing activities itself. However, fusing SR31 to two modestly neutralizing sybodies dramatically increases their affinity for RBD and neutralization activity against SARS-CoV-2 pseudovirus. Our work presents a tool protein and an efficient strategy to improve nanobody potency.


Assuntos
/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Anticorpos de Domínio Único/imunologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Anticorpos Antivirais/química , Anticorpos Antivirais/genética , Afinidade de Anticorpos , Sítios de Ligação , Cristalografia por Raios X , Células HEK293 , Humanos , Modelos Moleculares , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/genética
3.
Cell Host Microbe ; 29(3): 463-476.e6, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33592168

RESUMO

The evolution of SARS-CoV-2 could impair recognition of the virus by human antibody-mediated immunity. To facilitate prospective surveillance for such evolution, we map how convalescent plasma antibodies are impacted by all mutations to the spike's receptor-binding domain (RBD), the main target of plasma neutralizing activity. Binding by polyclonal plasma antibodies is affected by mutations in three main epitopes in the RBD, but longitudinal samples reveal that the impact of these mutations on antibody binding varies substantially both among individuals and within the same individual over time. Despite this inter- and intra-person heterogeneity, the mutations that most reduce antibody binding usually occur at just a few sites in the RBD's receptor-binding motif. The most important site is E484, where neutralization by some plasma is reduced >10-fold by several mutations, including one in the emerging 20H/501Y.V2 and 20J/501Y.V3 SARS-CoV-2 lineages. Going forward, these plasma escape maps can inform surveillance of SARS-CoV-2 evolution.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , /genética , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto , Idoso , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Sítios de Ligação , Linhagem Celular , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Estudos Prospectivos , Ligação Proteica , Domínios Proteicos , Receptores Virais/genética , Receptores Virais/imunologia , Adulto Jovem
4.
Science ; 371(6525): 194-200, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33414220

RESUMO

Medically important flaviviruses cause diverse disease pathologies and collectively are responsible for a major global disease burden. A contributing factor to pathogenesis is secreted flavivirus nonstructural protein 1 (NS1). Despite demonstrated protection by NS1-specific antibodies against lethal flavivirus challenge, the structural and mechanistic basis remains unknown. Here, we present three crystal structures of full-length dengue virus NS1 complexed with a flavivirus-cross-reactive, NS1-specific monoclonal antibody, 2B7, at resolutions between 2.89 and 3.96 angstroms. These structures reveal a protective mechanism by which two domains of NS1 are antagonized simultaneously. The NS1 wing domain mediates cell binding, whereas the ß-ladder triggers downstream events, both of which are required for dengue, Zika, and West Nile virus NS1-mediated endothelial dysfunction. These observations provide a mechanistic explanation for 2B7 protection against NS1-induced pathology and demonstrate the potential of one antibody to treat infections by multiple flaviviruses.


Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Vírus da Dengue/imunologia , Proteínas não Estruturais Virais/imunologia , Vírus do Nilo Ocidental/imunologia , Zika virus/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Reações Cruzadas , Cristalografia por Raios X , Dengue/prevenção & controle , Dengue/terapia , Endotélio/imunologia , Glicocálix/imunologia , Humanos , Camundongos , Conformação Proteica em Folha beta , Domínios Proteicos , Proteínas não Estruturais Virais/química , Febre do Nilo Ocidental/prevenção & controle , Febre do Nilo Ocidental/terapia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/terapia
5.
Science ; 371(6530)2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436526

RESUMO

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread, with devastating consequences. For passive immunization efforts, nanobodies have size and cost advantages over conventional antibodies. In this study, we generated four neutralizing nanobodies that target the receptor binding domain of the SARS-CoV-2 spike protein. We used x-ray crystallography and cryo-electron microscopy to define two distinct binding epitopes. On the basis of these structures, we engineered multivalent nanobodies with more than 100 times the neutralizing activity of monovalent nanobodies. Biparatopic nanobody fusions suppressed the emergence of escape mutants. Several nanobody constructs neutralized through receptor binding competition, whereas other monovalent and biparatopic nanobodies triggered aberrant activation of the spike fusion machinery. These premature conformational changes in the spike protein forestalled productive fusion and rendered the virions noninfectious.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , /imunologia , Anticorpos de Domínio Único/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Substituição de Aminoácidos , Animais , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/química , Anticorpos Antivirais/metabolismo , Afinidade de Anticorpos , Antígenos Virais/imunologia , Sítios de Ligação de Anticorpos , Linhagem Celular , Microscopia Crioeletrônica , Epitopos , Humanos , Fusão de Membrana , Mutação , Ligação Proteica , Conformação Proteica , Domínios Proteicos , /genética , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Replicação Viral
6.
Food Chem Toxicol ; 149: 112009, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33503469

RESUMO

SARS-CoV-2 is the coronavirus that originated in Wuhan in December 2019 and has spread globally. Studies have shown that smokers are less likely to be diagnosed with or be hospitalized for COVID-19 but, once hospitalized, have higher odds for an adverse outcome. We have previously presented the potential interaction between SARS-CoV-2 Spike glycoprotein and nicotinic acetylcholine receptors (nAChRs), due to a "toxin-like" epitope on the Spike glycoprotein, with homology to a sequence of a snake venom toxin. This epitope coincides with the well-described cryptic epitope for the human anti-SARS-CoV antibody CR3022. In this study, we present the molecular complexes of both SARS-CoV and SARS-CoV-2 Spike glycoproteins, at their open or closed conformations, with the model of the human α7 nAChR. We found that all studied protein complexes' interface involves a large part of the "toxin-like" sequences of SARS-CoV and SARS-CoV-2 Spike glycoproteins and toxin binding site of human α7 nAChR. Our findings provide further support to the hypothesis about the protective role of nicotine and other cholinergic agonists. The potential therapeutic role of CR3022 and other similar monoclonal antibodies with increased affinity for SARS-CoV-2 Spike glycoprotein against the clinical effects originating from the dysregulated cholinergic pathway should be further explored.


Assuntos
/virologia , Epitopos , Nicotina/farmacologia , Vírus da SARS/química , Glicoproteína da Espícula de Coronavírus/química , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Sequência de Aminoácidos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antivirais/química , Anticorpos Antivirais/uso terapêutico , Sítios de Ligação de Anticorpos , /prevenção & controle , Humanos , Modelos Moleculares , Agonistas Nicotínicos/química , Agonistas Nicotínicos/uso terapêutico , Sistema Colinérgico não Neuronal , Pandemias , Fatores de Proteção , Conformação Proteica , Homologia de Sequência , Transdução de Sinais , Fumantes , Fumar , Venenos de Serpentes/química
7.
Viruses ; 13(1)2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33467558

RESUMO

Adenovirus (AdV) infection elicits a strong immune response with the production of neutralizing antibodies and opsonization by complement and coagulation factors. One anti-hexon neutralizing antibody, called 9C12, is known to activate the complement cascade, resulting in the deposition of complement component C4b on the capsid, and the neutralization of the virus. The mechanism of AdV neutralization by C4b is independent of downstream complement proteins and involves the blockage of the release of protein VI, which is required for viral escape from the endosome. To investigate the structural basis underlying how C4b blocks the uncoating of AdV, we built a model for the complex of human adenovirus type-5 (HAdV5) with 9C12, together with complement components C1 and C4b. This model positions C4b near the Arg-Gly-Asp (RGD) loops of the penton base. There are multiple amino acids in the RGD loop that might serve as covalent binding sites for the reactive thioester of C4b. Molecular dynamics simulations with a multimeric penton base and C4b indicated that stabilizing interactions may form between C4b and multiple RGD loops. We propose that C4b deposition on one RGD loop leads to the entanglement of C4b with additional RGD loops on the same penton base multimer and that this entanglement blocks AdV uncoating.


Assuntos
Adenoviridae/imunologia , Complemento C4/química , Complemento C4/imunologia , Modelos Moleculares , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Sítios de Ligação , Capsídeo/química , Capsídeo/metabolismo , Capsídeo/ultraestrutura , Proteínas do Capsídeo/química , Proteínas do Capsídeo/imunologia , Proteínas do Capsídeo/metabolismo , Proteínas do Capsídeo/ultraestrutura , Humanos , Imunoglobulina G/química , Imunoglobulina G/imunologia , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade
8.
Commun Biol ; 4(1): 129, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514825

RESUMO

Development of antibody protection during SARS-CoV-2 infection is a pressing question for public health and for vaccine development. We developed highly sensitive SARS-CoV-2-specific antibody and neutralization assays. SARS-CoV-2 Spike protein or Nucleocapsid protein specific IgG antibodies at titers more than 1:100,000 were detectable in all PCR+ subjects (n = 115) and were absent in the negative controls. Other isotype antibodies (IgA, IgG1-4) were also detected. SARS-CoV-2 neutralization was determined in COVID-19 and convalescent plasma at up to 10,000-fold dilution, using Spike protein pseudotyped lentiviruses, which were also blocked by neutralizing antibodies (NAbs). Hospitalized patients had up to 3000-fold higher antibody and neutralization titers compared to outpatients or convalescent plasma donors. Interestingly, some COVID-19 patients also possessed NAbs against SARS-CoV Spike protein pseudovirus. Together these results demonstrate the high specificity and sensitivity of our assays, which may impact understanding the quality or duration of the antibody response during COVID-19 and in determining the effectiveness of potential vaccines.


Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , /química , Glicoproteína da Espícula de Coronavírus/química , Adulto , /imunologia , Anticorpos Neutralizantes/biossíntese , Anticorpos Antivirais/biossíntese , /virologia , Convalescença , /metabolismo , Ensaio de Imunoadsorção Enzimática/métodos , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Feminino , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Soros Imunes/química , Imunidade Humoral , Lentivirus/genética , Lentivirus/imunologia , Masculino , Pessoa de Meia-Idade , Testes de Neutralização , Fosfoproteínas/química , Fosfoproteínas/imunologia , Fosfoproteínas/metabolismo , Ligação Proteica , Receptores Virais/química , Receptores Virais/imunologia , Receptores Virais/metabolismo , /patogenicidade , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/metabolismo , Análise de Sobrevida
9.
Nat Commun ; 12(1): 264, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33431876

RESUMO

The ongoing pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Neutralizing antibodies against SARS-CoV-2 are an option for drug development for treating COVID-19. Here, we report the identification and characterization of two groups of mouse neutralizing monoclonal antibodies (MAbs) targeting the receptor-binding domain (RBD) on the SARS-CoV-2 spike (S) protein. MAbs 2H2 and 3C1, representing the two antibody groups, respectively, bind distinct epitopes and are compatible in formulating a noncompeting antibody cocktail. A humanized version of the 2H2/3C1 cocktail is found to potently neutralize authentic SARS-CoV-2 infection in vitro with half inhibitory concentration (IC50) of 12 ng/mL and effectively treat SARS-CoV-2-infected mice even when administered at as late as 24 h post-infection. We determine an ensemble of cryo-EM structures of 2H2 or 3C1 Fab in complex with the S trimer up to 3.8 Å resolution, revealing the conformational space of the antigen-antibody complexes and MAb-triggered stepwise allosteric rearrangements of the S trimer, delineating a previously uncharacterized dynamic process of coordinated binding of neutralizing antibodies to the trimeric S protein. Our findings provide important information for the development of MAb-based drugs for preventing and treating SARS-CoV-2 infections.


Assuntos
Anticorpos Monoclonais/química , Anticorpos Monoclonais/farmacologia , Anticorpos Antivirais/química , Anticorpos Antivirais/farmacologia , /efeitos dos fármacos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Microscopia Crioeletrônica , Mapeamento de Epitopos , Epitopos , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Ligação Proteica/efeitos dos fármacos , Conformação Proteica , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia
10.
Trends Microbiol ; 29(3): 195-203, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33446406

RESUMO

Camelid-derived and synthetic single-domain antibodies (sdAbs) are emerging as potent weapons against the novel coronavirus, SARS-CoV-2. sdAbs are small, compact, thermostable immunoglobulin elements capable of binding targets with subnanomolar affinities. By leveraging the power of phage- and yeast surface-display technologies, rare sdAbs can be isolated from highly diverse and complex antibody libraries. Once in hand, sdAbs can be engineered to improve binding affinity, avidity, target specificities, and biodistribution. In this Opinion piece we highlight a series of sophisticated studies describing the identification of ultrapotent sdAbs directed against the receptor-binding domain (RBD) of the SARS-CoV-2 Spike protein. We discuss the possible applications of these antibodies in the global fight against COVID-19.


Assuntos
Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Humanos , Estrutura Terciária de Proteína , Biologia Sintética/métodos
11.
Science ; 371(6525): 190-194, 2021 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-33414219

RESUMO

There are no approved flaviviral therapies and the development of vaccines against flaviruses has the potential of being undermined by antibody-dependent enhancement (ADE). The flavivirus nonstructural protein 1 (NS1) is a promising vaccine antigen with low ADE risk but has yet to be explored as a broad-spectrum therapeutic antibody target. Here, we provide the structural basis of NS1 antibody cross-reactivity through cocrystallization of the antibody 1G5.3 with NS1 proteins from dengue and Zika viruses. The 1G5.3 antibody blocks multi-flavivirus NS1-mediated cell permeability in disease-relevant cell lines, and therapeutic application of 1G5.3 reduces viremia and improves survival in dengue, Zika, and West Nile virus murine models. Finally, we demonstrate that 1G5.3 protection is independent of effector function, identifying the 1G5.3 epitope as a key site for broad-spectrum antiviral development.


Assuntos
Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Vírus da Dengue/imunologia , Proteínas não Estruturais Virais/imunologia , Vírus do Nilo Ocidental/imunologia , Zika virus/imunologia , Animais , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/uso terapêutico , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/uso terapêutico , Células CHO , Linhagem Celular , Cricetulus , Reações Cruzadas , Dengue/prevenção & controle , Dengue/terapia , Modelos Animais de Doenças , Humanos , Camundongos , Domínios Proteicos , Proteínas não Estruturais Virais/química , Viremia/terapia , Febre do Nilo Ocidental/prevenção & controle , Febre do Nilo Ocidental/terapia , Infecção por Zika virus/prevenção & controle , Infecção por Zika virus/terapia
12.
Nat Struct Mol Biol ; 28(2): 128-131, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33402708

RESUMO

The SARS-CoV-2 spike (S) protein, a primary target for COVID-19 vaccine development, presents its receptor binding domain in two conformations, the receptor-accessible 'up' or receptor-inaccessible 'down' states. Here we report that the commonly used stabilized S ectodomain construct '2P' is sensitive to cold temperatures, and this cold sensitivity is abrogated in a 'down' state-stabilized ectodomain. Our findings will impact structural, functional and vaccine studies that use the SARS-CoV-2 S ectodomain.


Assuntos
Glicoproteína da Espícula de Coronavírus/química , Anticorpos Antivirais/química , Temperatura Baixa , Microscopia Crioeletrônica , Ensaio de Imunoadsorção Enzimática , Humanos , Desnaturação Proteica , Domínios Proteicos , Estabilidade Proteica , Glicoproteína da Espícula de Coronavírus/ultraestrutura , Ressonância de Plasmônio de Superfície
13.
Science ; 371(6532)2021 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-33361116

RESUMO

Immunoglobulin G (IgG) antibodies are crucial for protection against invading pathogens. A highly conserved N-linked glycan within the IgG-Fc tail, which is essential for IgG function, shows variable composition in humans. Afucosylated IgG variants are already used in anticancer therapeutic antibodies for their increased activity through Fc receptors (FcγRIIIa). Here, we report that afucosylated IgG (approximately 6% of total IgG in humans) are specifically formed against enveloped viruses but generally not against other antigens. This mediates stronger FcγRIIIa responses but also amplifies brewing cytokine storms and immune-mediated pathologies. Critically ill COVID-19 patients, but not those with mild symptoms, had high concentrations of afucosylated IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), amplifying proinflammatory cytokine release and acute phase responses. Thus, antibody glycosylation plays a critical role in immune responses to enveloped viruses, including COVID-19.


Assuntos
Anticorpos Antivirais/imunologia , Imunoglobulina G/imunologia , /imunologia , Adulto , Idoso , Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Células Cultivadas , Estado Terminal , Citomegalovirus/imunologia , Feminino , Fucose/análise , Glicosilação , HIV/imunologia , Vacinas contra Hepatite B/imunologia , Humanos , Fragmentos Fc das Imunoglobulinas/química , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/química , Inflamação , Interleucina-6/biossíntese , Interleucina-6/imunologia , Macrófagos/imunologia , Masculino , Pessoa de Meia-Idade , Parvovirus B19 Humano/imunologia , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas de Subunidades/imunologia , Adulto Jovem
14.
Bioanalysis ; 13(1): 13-28, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33319585

RESUMO

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.


Assuntos
/normas , Teste em Amostras de Sangue Seco/normas , Ensaio de Imunoadsorção Enzimática/normas , /imunologia , Anticorpos Antivirais/química , Antígenos Virais/sangue , Antígenos Virais/imunologia , /imunologia , /sangue , Feminino , Humanos , Imunoglobulina G/química , Masculino , Pessoa de Meia-Idade , Fosfoproteínas/sangue , Fosfoproteínas/imunologia , Kit de Reagentes para Diagnóstico/normas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/sangue , Glicoproteína da Espícula de Coronavírus/imunologia
15.
PLoS One ; 15(12): e0239112, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33382708

RESUMO

Influenza virus A is a significant agent involved in the outbreak of worldwide epidemics, causing millions of fatalities around the world by respiratory diseases and seasonal illness. Many projects had been conducting to investigate recovered infected patients for therapeutic vaccines that have broad-spectrum activity. With the aid of the computational approach in biology, the designation for a vaccine model is more accessible. We developed an in silico protocol called iBRAB to design a broad-reactive Fab on a wide range of influenza A virus. The Fab model was constructed based on sequences and structures of available broad-spectrum Abs or Fabs against a wide range of H1N1 influenza A virus. As a result, the proposed Fab model followed iBRAB has good binding affinity over 27 selected HA of different strains of H1 influenza A virus, including wild-type and mutated ones. The examination also took by computational tools to fasten the procedure. This protocol could be applied for a fast-designed therapeutic vaccine against different types of threats.


Assuntos
Anticorpos Antivirais/química , Antígenos Virais/química , Desenho de Fármacos , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Fragmentos Fab das Imunoglobulinas/química , Vírus da Influenza A Subtipo H1N1/imunologia , Influenza Humana/prevenção & controle , Sequência de Aminoácidos , Anticorpos Antivirais/genética , Antígenos Virais/genética , Antígenos Virais/imunologia , Sítios de Ligação , Simulação por Computador , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Humanos , Fragmentos Fab das Imunoglobulinas/genética , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/biossíntese , Influenza Humana/imunologia , Influenza Humana/virologia , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Termodinâmica
16.
Front Immunol ; 11: 570018, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33042151

RESUMO

The pandemic of Coronavirus Disease 2019 (COVID-19) caused by SARS-CoV-2 has induced global eagerness to develop vaccines and therapeutics for treating COVID-19, including neutralizing antibodies. To develop effective therapeutic antibodies against SARS-CoV-2, it is critical to understand the interaction between viral and host's proteins. The human ACE2 (hACE2) protein is the crucial target for the SARS-CoV's Spike protein that allows the virus to adhere to host epithelial cells. X-ray crystal structures and biophysical properties of protein-protein interactions reveal a large interaction surface with high binding-affinity between SARS-CoV-2 and hACE2 (18 interactions), at least 15-fold stronger than between SARS-CoV-1 and hACE2 (eight interactions). This suggests that antibodies against CoV-1 infection might not be very efficient against CoV-2. Furthermore, interspecies comparisons indicate that ACE2 proteins of man and cat are far closer than dog, ferret, mouse, and rat with significant differences in binding-affinity between Spike and ACE2 proteins. This strengthens the notion of productive SARS-CoV-2 transmission between felines and humans and that classical animal models are not optimally suited for evaluating therapeutic antibodies. The large interaction surface with strong affinity between SARS-CoV-2 and hACE2 (dG-12.4) poses a huge challenge to develop reliable antibody therapy that truly blocks SARS-CoV-2 adherence and infection. We gauge that single antibodies against single epitopes might not sufficiently interfere with the strong interaction-synapse between Spike and hACE2 proteins. Instead, appropriate combinations of high-affinity neutralizing antibodies against different epitopes might be needed, preferably of IgA-class for optimal and prolonged activity at epithelial layers of respiratory and intestine tracts.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Afinidade de Anticorpos , Betacoronavirus , Peptidil Dipeptidase A , Glicoproteína da Espícula de Coronavírus , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Betacoronavirus/química , Betacoronavirus/imunologia , Cristalografia por Raios X , Humanos , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/imunologia , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia
17.
Nat Commun ; 11(1): 5253, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067459

RESUMO

Enterovirus 71 (EV71)-neutralizing antibodies correlate with protection and have potential as therapeutic agents. We isolate and characterize a panel of plasmablast-derived monoclonal antibodies from an infected child whose antibody response focuses on the plateau epitope near the icosahedral 3-fold axes. Eight of a total of 19 antibodies target this epitope and three of these potently neutralize the virus. Representative neutralizing antibodies 38-1-10A and 38-3-11A both confer effective protection against lethal EV71 challenge in hSCARB2-transgenic mice. The cryo-electron microscopy structures of the EV71 virion in complex with Fab fragments of these potent and protective antibodies reveal the details of a conserved epitope formed by residues in the BC and HI loops of VP2 and the BC and HI loops of VP3 spanning the region around the 3-fold axis. Remarkably, the two antibodies interact with the epitope in quite distinct ways. These plateau-binding antibodies provide templates for promising candidate therapeutics.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Enterovirus Humano A/imunologia , Infecções por Enterovirus/imunologia , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/química , Anticorpos Antivirais/química , Proteínas do Capsídeo/química , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/imunologia , Enterovirus Humano A/química , Enterovirus Humano A/genética , Infecções por Enterovirus/virologia , Epitopos/química , Epitopos/genética , Epitopos/imunologia , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Testes de Neutralização
18.
Diabetologia ; 63(12): 2548-2558, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33029657

RESUMO

AIMS/HYPOTHESIS: The aim of the study was to characterise the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with diabetes. Demonstrating the ability to mount an appropriate antibody response in the presence of hyperglycaemia is relevant for the comprehension of mechanisms related to the observed worse clinical outcome of coronavirus disease 2019 (COVID-19) pneumonia in patients with diabetes and for the development of any future vaccination campaign to prevent SARS-CoV-2 infection. METHODS: Using a highly specific and sensitive measurement of antibodies by fluid-phase luciferase immunoprecipitation assays, we characterised the IgG, IgM and IgA response against multiple antigens of SARS-CoV-2 in a cohort of 509 patients with documented diagnosis of COVID-19, prospectively followed at our institution. We analysed clinical outcomes and antibody titres according to the presence of hyperglycaemia, i.e., either diagnosed or undiagnosed diabetes, at the time of, or during, hospitalisation. RESULTS: Among patients with confirmed COVID-19, 139 (27.3%) had diabetes: 90 (17.7%) had diabetes diagnosed prior to the hospital admission (comorbid diabetes) while 49 (9.6%) had diabetes diagnosed at the time of admission (newly diagnosed). Diabetes was associated with increased levels of inflammatory biomarkers and hypercoagulopathy, as well as leucocytosis and neutrophilia. Diabetes was independently associated with risk of death (HR 2.32 [95% CI 1.44, 3.75], p = 0.001), even after adjustment for age, sex and other relevant comorbidities. Moreover, a strong association between higher glucose levels and risk of death was documented irrespective of diabetes diagnosis (HR 1.14 × 1.1 mmol/l [95% CI 1.08, 1.21], p < 0.001). The humoral response against SARS-CoV-2 in patients with diabetes was present and superimposable, as for timing and antibody titres, to that of non-diabetic patients, with marginal differences, and was not influenced by glucose levels. Of the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike receptor-binding domain (RBD) was predictive of survival rate, both in the presence or absence of diabetes. CONCLUSIONS/INTERPRETATION: The observed increased severity and mortality risk of COVID-19 pneumonia in patients with hyperglycaemia was not the result of an impaired humoral response against SARS-CoV-2. RBD IgG positivity was associated with a remarkable protective effect, allowing for a cautious optimism about the efficacy of future vaccines against SARs-COV-2 in people with diabetes. Graphical abstract.


Assuntos
Formação de Anticorpos , Antígenos Virais/imunologia , Infecções por Coronavirus/imunologia , Diabetes Mellitus/imunologia , Pneumonia Viral/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/isolamento & purificação , Biomarcadores/análise , Transtornos da Coagulação Sanguínea/complicações , Transtornos da Coagulação Sanguínea/imunologia , Glicemia/análise , Estudos de Coortes , Infecções por Coronavirus/mortalidade , Feminino , Humanos , Imunidade Humoral , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/mortalidade , Fatores de Risco , Análise de Sobrevida
19.
Cell ; 183(4): 1024-1042.e21, 2020 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-32991844

RESUMO

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.


Assuntos
Anticorpos Neutralizantes/imunologia , Mapeamento de Epitopos/métodos , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/química , Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Reações Antígeno-Anticorpo , Betacoronavirus/imunologia , Betacoronavirus/isolamento & purificação , Betacoronavirus/metabolismo , Sítios de Ligação , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Epitopos/química , Epitopos/imunologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina A/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Cinética , Simulação de Dinâmica Molecular , Pandemias , Peptidil Dipeptidase A/química , Peptidil Dipeptidase A/metabolismo , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Domínios Proteicos/imunologia , Estrutura Quaternária de Proteína , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo
20.
Cell ; 183(2): 429-441.e16, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32941803

RESUMO

Novel COVID-19 therapeutics are urgently needed. We generated a phage-displayed human antibody VH domain library from which we identified a high-affinity VH binder ab8. Bivalent VH, VH-Fc ab8, bound with high avidity to membrane-associated S glycoprotein and to mutants found in patients. It potently neutralized mouse-adapted SARS-CoV-2 in wild-type mice at a dose as low as 2 mg/kg and exhibited high prophylactic and therapeutic efficacy in a hamster model of SARS-CoV-2 infection, possibly enhanced by its relatively small size. Electron microscopy combined with scanning mutagenesis identified ab8 interactions with all three S protomers and showed how ab8 neutralized the virus by directly interfering with ACE2 binding. VH-Fc ab8 did not aggregate and did not bind to 5,300 human membrane-associated proteins. The potent neutralization activity of VH-Fc ab8 combined with good developability properties and cross-reactivity to SARS-CoV-2 mutants provide a strong rationale for its evaluation as a COVID-19 therapeutic.


Assuntos
Infecções por Coronavirus/tratamento farmacológico , Cadeias Pesadas de Imunoglobulinas/administração & dosagem , Região Variável de Imunoglobulina/administração & dosagem , Biblioteca de Peptídeos , Pneumonia Viral/tratamento farmacológico , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/ultraestrutura , Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/química , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/ultraestrutura , Afinidade de Anticorpos , Cricetinae , Feminino , Humanos , Fragmentos Fc das Imunoglobulinas/imunologia , Cadeias Pesadas de Imunoglobulinas/química , Cadeias Pesadas de Imunoglobulinas/imunologia , Cadeias Pesadas de Imunoglobulinas/ultraestrutura , Região Variável de Imunoglobulina/química , Região Variável de Imunoglobulina/imunologia , Região Variável de Imunoglobulina/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Pandemias , Peptidil Dipeptidase A/metabolismo , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Glicoproteína da Espícula de Coronavírus/ultraestrutura
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...