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1.
Cell ; 187(6): 1363-1373.e12, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38366591

RESUMO

In response to the 2022 outbreak of mpox driven by unprecedented human-to-human monkeypox virus (MPXV) transmission, we designed BNT166, aiming to create a highly immunogenic, safe, accessible, and scalable next-generation vaccine against MPXV and related orthopoxviruses. To address the multiple viral forms and increase the breadth of immune response, two candidate multivalent mRNA vaccines were evaluated pre-clinically: a quadrivalent vaccine (BNT166a; encoding the MPXV antigens A35, B6, M1, H3) and a trivalent vaccine (BNT166c; without H3). Both candidates induced robust T cell responses and IgG antibodies in mice, including neutralizing antibodies to both MPXV and vaccinia virus. In challenge studies, BNT166a and BNT166c provided complete protection from vaccinia, clade I, and clade IIb MPXV. Furthermore, immunization with BNT166a was 100% effective at preventing death and at suppressing lesions in a lethal clade I MPXV challenge in cynomolgus macaques. These findings support the clinical evaluation of BNT166, now underway (NCT05988203).


Assuntos
Monkeypox virus , Mpox , Vacina Antivariólica , Animais , Humanos , Camundongos , Macaca fascicularis , Monkeypox virus/genética , Mpox/imunologia , Mpox/prevenção & controle , Vacinas Combinadas , Vaccinia virus/genética
2.
Cell ; 186(11): 2392-2409.e21, 2023 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-37164012

RESUMO

T cell responses play an important role in protection against beta-coronavirus infections, including SARS-CoV-2, where they associate with decreased COVID-19 disease severity and duration. To enhance T cell immunity across epitopes infrequently altered in SARS-CoV-2 variants, we designed BNT162b4, an mRNA vaccine component that is intended to be combined with BNT162b2, the spike-protein-encoding vaccine. BNT162b4 encodes variant-conserved, immunogenic segments of the SARS-CoV-2 nucleocapsid, membrane, and ORF1ab proteins, targeting diverse HLA alleles. BNT162b4 elicits polyfunctional CD4+ and CD8+ T cell responses to diverse epitopes in animal models, alone or when co-administered with BNT162b2 while preserving spike-specific immunity. Importantly, we demonstrate that BNT162b4 protects hamsters from severe disease and reduces viral titers following challenge with viral variants. These data suggest that a combination of BNT162b2 and BNT162b4 could reduce COVID-19 disease severity and duration caused by circulating or future variants. BNT162b4 is currently being clinically evaluated in combination with the BA.4/BA.5 Omicron-updated bivalent BNT162b2 (NCT05541861).


Assuntos
Vacina BNT162 , COVID-19 , Animais , Cricetinae , Humanos , Anticorpos Neutralizantes , Anticorpos Antivirais , COVID-19/prevenção & controle , Epitopos , SARS-CoV-2/genética
3.
Cell ; 184(19): 4969-4980.e15, 2021 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-34332650

RESUMO

Memory B cell reserves can generate protective antibodies against repeated SARS-CoV-2 infections, but with unknown reach from original infection to antigenically drifted variants. We charted memory B cell receptor-encoded antibodies from 19 COVID-19 convalescent subjects against SARS-CoV-2 spike (S) and found seven major antibody competition groups against epitopes recurrently targeted across individuals. Inclusion of published and newly determined structures of antibody-S complexes identified corresponding epitopic regions. Group assignment correlated with cross-CoV-reactivity breadth, neutralization potency, and convergent antibody signatures. Although emerging SARS-CoV-2 variants of concern escaped binding by many members of the groups associated with the most potent neutralizing activity, some antibodies in each of those groups retained affinity-suggesting that otherwise redundant components of a primary immune response are important for durable protection from evolving pathogens. Our results furnish a global atlas of S-specific memory B cell repertoires and illustrate properties driving viral escape and conferring robustness against emerging variants.

4.
Cell ; 183(6): 1496-1507.e16, 2020 12 10.
Artigo em Inglês | MEDLINE | ID: mdl-33171099

RESUMO

Antibodies are key immune effectors that confer protection against pathogenic threats. The nature and longevity of the antibody response to SARS-CoV-2 infection are not well defined. We charted longitudinal antibody responses to SARS-CoV-2 in 92 subjects after symptomatic COVID-19. Antibody responses to SARS-CoV-2 are unimodally distributed over a broad range, with symptom severity correlating directly with virus-specific antibody magnitude. Seventy-six subjects followed longitudinally to ∼100 days demonstrated marked heterogeneity in antibody duration dynamics. Virus-specific IgG decayed substantially in most individuals, whereas a distinct subset had stable or increasing antibody levels in the same time frame despite similar initial antibody magnitudes. These individuals with increasing responses recovered rapidly from symptomatic COVID-19 disease, harbored increased somatic mutations in virus-specific memory B cell antibody genes, and had persistent higher frequencies of previously activated CD4+ T cells. These findings illuminate an efficient immune phenotype that connects symptom clearance speed to differential antibody durability dynamics.


Assuntos
Anticorpos Antivirais/imunologia , Formação de Anticorpos , Linfócitos T CD4-Positivos/imunologia , COVID-19 , Imunoglobulina G/imunologia , Ativação Linfocitária , Mutação , COVID-19/genética , COVID-19/imunologia , Humanos , SARS-CoV-2/genética , SARS-CoV-2/imunologia
5.
Nature ; 535(7610): 164-8, 2016 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-27383988

RESUMO

Flaviviruses infect hundreds of millions of people annually, and no antiviral therapy is available. We performed a genome-wide CRISPR/Cas9-based screen to identify host genes that, when edited, resulted in reduced flavivirus infection. Here, we validated nine human genes required for flavivirus infectivity, and these were associated with endoplasmic reticulum functions including translocation, protein degradation, and N-linked glycosylation. In particular, a subset of endoplasmic reticulum-associated signal peptidase complex (SPCS) proteins was necessary for proper cleavage of the flavivirus structural proteins (prM and E) and secretion of viral particles. Loss of SPCS1 expression resulted in markedly reduced yield of all Flaviviridae family members tested (West Nile, Dengue, Zika, yellow fever, Japanese encephalitis, and hepatitis C viruses), but had little impact on alphavirus, bunyavirus, or rhabdovirus infection or the surface expression or secretion of diverse host proteins. We found that SPCS1 dependence could be bypassed by replacing the native prM protein leader sequences with a class I major histocompatibility complex (MHC) antigen leader sequence. Thus, SPCS1, either directly or indirectly via its interactions with unknown host proteins, preferentially promotes the processing of specific protein cargo, and Flaviviridae have a unique dependence on this signal peptide processing pathway. SPCS1 and other signal processing pathway members could represent pharmacological targets for inhibiting infection by the expanding number of flaviviruses of medical concern.


Assuntos
Sistemas CRISPR-Cas/genética , Flavivirus/fisiologia , Genoma Humano/genética , Fatores Celulares Derivados do Hospedeiro/genética , Sinais Direcionadores de Proteínas/fisiologia , Animais , Linhagem Celular , Drosophila/citologia , Drosophila/genética , Drosophila/virologia , Descoberta de Drogas , Retículo Endoplasmático/metabolismo , Feminino , Flavivirus/metabolismo , Infecções por Flavivirus/genética , Infecções por Flavivirus/virologia , Glicosilação , Interações Hospedeiro-Patógeno/genética , Humanos , Proteínas de Membrana/genética , Terapia de Alvo Molecular , Transporte Proteico/genética , Proteólise , Reprodutibilidade dos Testes , Serina Endopeptidases/genética , Especificidade da Espécie , Proteínas Virais/química , Proteínas Virais/metabolismo , Proteínas Estruturais Virais/metabolismo
6.
Proc Natl Acad Sci U S A ; 114(40): E8411-E8420, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28923960

RESUMO

Ig heavy chain (IgH) isotypes (e.g., IgM, IgG, and IgE) are generated as secreted/soluble antibodies (sIg) or as membrane-bound (mIg) B cell receptors (BCRs) through alternative RNA splicing. IgH isotype dictates soluble antibody function, but how mIg isotype influences B cell behavior is not well defined. We examined IgH isotype-specific BCR function by analyzing naturally switched B cells from wild-type mice, as well as by engineering polyclonal Ighγ1/γ1 and Ighε/ε mice, which initially produce IgG1 or IgE from their respective native genomic configurations. We found that B cells from wild-type mice, as well as Ighγ1/γ1 and Ighε/ε mice, produce transcripts that generate IgM, IgG1, and IgE in an alternative splice form bias hierarchy, regardless of cell stage. In this regard, we found that mIgµ > mIgγ1 > mIgε, and that these BCR expression differences influence respective developmental fitness. Restrained B cell development from Ighγ1/γ1 and Ighε/ε mice was proportional to sIg/mIg ratios and was rescued by enforced expression of the respective mIgs. In addition, artificially enhancing BCR signal strength permitted IgE+ memory B cells-which essentially do not exist under normal conditions-to provide long-lived memory function, suggesting that quantitative BCR signal weakness contributes to restraint of IgE B cell responses. Our results indicate that IgH isotype-specific mIg/BCR dosage may play a larger role in B cell fate than previously anticipated.


Assuntos
Linfócitos B/fisiologia , Switching de Imunoglobulina , Imunoglobulina E/metabolismo , Imunoglobulina G/metabolismo , Cadeias Pesadas de Imunoglobulinas/metabolismo , Imunoglobulina M/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Animais , Linfócitos B/citologia , Feminino , Perfilação da Expressão Gênica , Imunoglobulina E/genética , Imunoglobulina G/genética , Cadeias Pesadas de Imunoglobulinas/genética , Imunoglobulina M/genética , Masculino , Camundongos
7.
J Virol ; 90(23): 10499-10512, 2016 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-27630236

RESUMO

While natural hepatitis C virus (HCV) infection results in highly diverse quasispecies of related viruses over time, mutations accumulate more slowly in tissue culture, in part because of the inefficiency of replication in cells. To create a highly diverse population of HCV particles in cell culture and identify novel growth-enhancing mutations, we engineered a library of infectious HCV with all codons represented at most positions in the ectodomain of the E2 gene. We identified many putative growth-adaptive mutations and selected nine highly represented E2 mutants for further study: Q412R, T416R, S449P, T563V, A579R, L619T, V626S, K632T, and L644I. We evaluated these mutants for changes in particle-to-infectious-unit ratio, sensitivity to neutralizing antibody or CD81 large extracellular loop (CD81-LEL) inhibition, entry factor usage, and buoyant density profiles. Q412R, T416R, S449P, T563V, and L619T were neutralized more efficiently by anti-E2 antibodies and T416R, T563V, and L619T by CD81-LEL. Remarkably, all nine variants showed reduced dependence on scavenger receptor class B type I (SR-BI) for infection. This shift from SR-BI usage did not correlate with a change in the buoyant density profiles of the variants, suggesting an altered E2-SR-BI interaction rather than changes in the virus-associated lipoprotein-E2 interaction. Our results demonstrate that residues influencing SR-BI usage are distributed across E2 and support the development of large-scale mutagenesis studies to identify viral variants with unique functional properties. IMPORTANCE: Characterizing variant viruses can reveal new information about the life cycle of HCV and the roles played by different viral genes. However, it is difficult to recapitulate high levels of diversity in the laboratory because of limitations in the HCV culture system. To overcome this limitation, we engineered a library of mutations into the E2 gene in the context of an infectious clone of the virus. We used this library of viruses to identify nine mutations that enhance the growth rate of HCV. These growth-enhancing mutations reduced the dependence on a key entry receptor, SR-BI. By generating a highly diverse library of infectious HCV, we mapped regions of the E2 protein that influence a key virus-host interaction and provide proof of principle for the generation of large-scale mutant libraries for the study of pathogens with great sequence variability.


Assuntos
Hepacivirus/genética , Mutação , Receptores Depuradores Classe B/fisiologia , Proteínas do Envelope Viral/genética , Adaptação Fisiológica/genética , Substituição de Aminoácidos , Anticorpos Antivirais , Sistemas CRISPR-Cas , Linhagem Celular , Biblioteca Gênica , Engenharia Genética , Genoma Viral , Hepacivirus/crescimento & desenvolvimento , Hepacivirus/fisiologia , Hepatite C/imunologia , Hepatite C/prevenção & controle , Hepatite C/virologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Interações Hospedeiro-Patógeno/fisiologia , Humanos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Tetraspanina 28 , Proteínas do Envelope Viral/química , Proteínas do Envelope Viral/imunologia
8.
J Virol ; 90(6): 3112-22, 2016 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-26739044

RESUMO

UNLABELLED: Hypervariable region 1 (HVR1) (amino acids [aa] 384 to 410) on the E2 glycoprotein of hepatitis C virus contributes to persistent infection by evolving escape mutations that attenuate binding of inhibitory antibodies and by blocking access of broadly neutralizing antibodies to their epitopes. A third proposed mechanism of immune antagonism is that poorly neutralizing antibodies binding to HVR1 interfere with binding of other superior neutralizing antibodies. Epitope mapping of human monoclonal antibodies (HMAbs) that bind to an adjacent, conserved domain on E2 encompassing aa 412 to 423 revealed two subsets, designated HC33 HMAbs. While both subsets have contact residues within aa 412 to 423, alanine-scanning mutagenesis suggested that one subset, which includes HC33.8, has an additional contact residue within HVR1. To test for interference of anti-HVR1 antibodies with binding of antibodies to aa 412 to 423 and other E2 determinants recognized by broadly neutralizing HMAbs, two murine MAbs against HVR1 (H77.16) and aa 412 to 423 (H77.39) were studied. As expected, H77.39 inhibited the binding of all HC33 HMAbs. Unexpectedly, H77.16 also inhibited the binding of both subsets of HC33 HMAbs. This inhibition also was observed against other broadly neutralizing HMAbs to epitopes outside aa 412 to 423. Combination antibody neutralization studies by the median-effect analysis method with H77.16 and broadly reactive HMAbs revealed antagonism between these antibodies. Structural studies demonstrated conformational flexibility in this antigenic region, which supports the possibility of anti-HVR1 antibodies hindering the binding of broadly neutralizing MAbs. These findings support the hypothesis that anti-HVR1 antibodies can interfere with a protective humoral response against HCV infection. IMPORTANCE: HVR1 contributes to persistent infection by evolving mutations that escape from neutralizing antibodies to HVR1 and by shielding broadly neutralizing antibodies from their epitopes. This study provides insight into a new immune antagonism mechanism by which the binding of antibodies to HVR1 blocks the binding and activity of broadly neutralizing antibodies to HCV. Immunization strategies that avoid the induction of HVR1 antibodies should increase the inhibitory activity of broadly neutralizing anti-HCV antibodies elicited by candidate vaccines.


Assuntos
Anticorpos Neutralizantes/imunologia , Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Monoclonais/imunologia , Mapeamento de Epitopos , Epitopos de Linfócito B/imunologia , Camundongos , Ligação Proteica
9.
Clin Lab Med ; 42(1): 85-96, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35153050

RESUMO

Severe acute respiratory syndrome coronavirus 2 (COVID)-19 has emerged as the greatest global health threat in generations. An unprecedented mobilization of researchers has generated a wealth of data on humoral responses to SARS-CoV-2 within a year of the pandemic's beginning. The rapidly developed understanding of acute-phase antibody induction and medium-term antibody durability in COVID-19 is important at an individual level to inform patient care and a population level to help predict transmission dynamics. In this brief review, we will describe the development and maintenance of antibody responses to immunization and infections generally and the specific antibody dynamics observed for COVID-19. These crucial features of the humoral response have implications for the use of antibody therapeutics against the virus and can inform the likelihood of reinfection of individuals by the virus.


Assuntos
COVID-19 , Anticorpos Antivirais , Humanos , Imunoglobulina A , Imunoglobulina G , Imunoglobulina M , SARS-CoV-2
10.
Sci Immunol ; 7(78): eabp8328, 2022 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-35549298

RESUMO

Key features of immune memory are greater and faster antigen-specific antibody responses to repeat infection. In the setting of immune-evading viral evolution, it is important to understand how far antibody memory recognition stretches across viral variants when memory cells are recalled to action by repeat invasions. It is also important to understand how immune recall influences longevity of secreted antibody responses. We analyzed SARS-CoV-2 variant recognition; dynamics of memory B cells; and secreted antibody over time after infection, vaccination, and boosting. We find that a two-dose SARS-CoV-2 vaccination regimen given after natural infection generated greater longitudinal antibody stability and induced maximal antibody magnitudes with enhanced breadth across Beta, Gamma, Delta and Omicron variants. A homologous third messenger RNA vaccine dose in COVID-naïve individuals conferred greater cross-variant evenness of neutralization potency with stability that was equal to the hybrid immunity conferred by infection plus vaccination. Within unvaccinated individuals who recovered from COVID, enhanced antibody stability over time was observed within a subgroup of individuals who recovered more quickly from COVID and harbored significantly more memory B cells cross-reactive to endemic coronaviruses early after infection. These cross-reactive clones map to the conserved S2 region of SARS-CoV-2 spike with higher somatic hypermutation levels and greater target affinity. We conclude that SARS-CoV-2 antigen challenge histories in humans influence not only the speed and magnitude of antibody responses but also functional cross-variant antibody repertoire composition and longevity.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Vacinas contra COVID-19 , Anticorpos
11.
JCI Insight ; 6(1)2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33427208

RESUMO

The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coupled with a lack of therapeutics, has paralyzed the globe. Although significant effort has been invested in identifying antibodies that block infection, the ability of antibodies to target infected cells through Fc interactions may be vital to eliminate the virus. To explore the role of Fc activity in SARS-CoV-2 immunity, the functional potential of a cross-SARS-reactive antibody, CR3022, was assessed. CR3022 was able to broadly drive antibody effector functions, providing critical immune clearance at entry and upon egress. Using selectively engineered Fc variants, no protection was observed after administration of WT IgG1 in mice or hamsters. Conversely, the functionally enhanced Fc variant resulted in increased pathology in both the mouse and hamster models, causing weight loss in mice and enhanced viral replication and weight loss in the more susceptible hamster model, highlighting the pathological functions of Fc-enhancing mutations. These data point to the critical need for strategic Fc engineering for the treatment of SARS-CoV-2 infection.


Assuntos
Anticorpos Neutralizantes/farmacologia , COVID-19/imunologia , Imunidade Inata/efeitos dos fármacos , Fragmentos Fc das Imunoglobulinas/genética , Imunoglobulina G/farmacologia , SARS-CoV-2/efeitos dos fármacos , Replicação Viral/efeitos dos fármacos , Animais , Anticorpos Monoclonais , Anticorpos Neutralizantes/genética , Anticorpos Neutralizantes/uso terapêutico , COVID-19/fisiopatologia , Cricetinae , Reações Cruzadas , Epitopos , Humanos , Imunidade Inata/imunologia , Imunoglobulina G/genética , Imunoglobulina G/uso terapêutico , Mesocricetus , Camundongos , Coronavírus da Síndrome Respiratória do Oriente Médio/efeitos dos fármacos , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Engenharia de Proteínas , Receptores Fc/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/efeitos dos fármacos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Glicoproteína da Espícula de Coronavírus/imunologia , Células THP-1 , Carga Viral/efeitos dos fármacos , Redução de Peso/efeitos dos fármacos , Tratamento Farmacológico da COVID-19
12.
bioRxiv ; 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33758863

RESUMO

Memory B cell reserves can generate protective antibodies against repeated SARS-CoV-2 infections, but with an unknown reach from original infection to antigenically drifted variants. We charted memory B cell receptor-encoded monoclonal antibodies (mAbs) from 19 COVID-19 convalescent subjects against SARS-CoV-2 spike (S) and found 7 major mAb competition groups against epitopes recurrently targeted across individuals. Inclusion of published and newly determined structures of mAb-S complexes identified corresponding epitopic regions. Group assignment correlated with cross-CoV-reactivity breadth, neutralization potency, and convergent antibody signatures. mAbs that competed for binding the original S isolate bound differentially to S variants, suggesting the protective importance of otherwise-redundant recognition. The results furnish a global atlas of the S-specific memory B cell repertoire and illustrate properties conferring robustness against emerging SARS-CoV-2 variants.

13.
Biochemistry ; 49(41): 8847-56, 2010 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-20828170

RESUMO

Osmoregulatory transporters stimulate bacterial growth by mediating osmoprotectant uptake in response to increasing osmotic pressure. The ProP protein of Escherichia coli transports proline and other osmoprotectants. Like LacY, ProP is a member of the major facilitator superfamily and a H(+)-solute symporter. ProP is regulated by osmotic pressure via a membrane potential-dependent mechanism. A homology model predicts that ionizable and polar residues, highly conserved among ProP homologues, cluster deep within the N-terminal helix bundle of ProP. Chemical labeling of introduced cysteine (Cys) residues supported the homology model by confirming the predicted positions of transmembrane helix I (TMI) and periplasmic loop 1. Replacements of residues in the putative polar cluster impaired or altered ProP function, suggesting that they are important for osmosensing and may interact with the transport substrates. Asn34, Glu37, Phe41, Tyr44, and Ala48 line the most polar face of TMI; Tyr44 is on the periplasmic side of the putative polar cluster, and Ala59 is in periplasmic loop 1. The N-ethylmaleimide reactivities of Cys introduced at positions 41, 44, 48, and 59 increased with osmotic pressure, whereas the reactivities of those at cytoplasm-proximal positions 34 and 37 did not. Replacements of polar cluster residues that blocked transport also affected the NEM reactivity of Cys44 and its osmolality dependence. This report and previous work suggest that conformational changes associated with osmosensing may shift the equilibria between outward- and inward-facing transport pathway intermediates.


Assuntos
Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Periplasma/metabolismo , Simportadores/metabolismo , Transporte Biológico/fisiologia , Escherichia coli/química , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/genética , Modelos Moleculares , Osmose/fisiologia , Periplasma/química , Periplasma/genética , Prolina/química , Prolina/genética , Prolina/metabolismo , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Homologia Estrutural de Proteína , Simportadores/química , Simportadores/genética
14.
Science ; 370(6520)2020 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-32994364

RESUMO

Understanding humoral responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for improving diagnostics, therapeutics, and vaccines. Deep serological profiling of 232 coronavirus disease 2019 (COVID-19) patients and 190 pre-COVID-19 era controls using VirScan revealed more than 800 epitopes in the SARS-CoV-2 proteome, including 10 epitopes likely recognized by neutralizing antibodies. Preexisting antibodies in controls recognized SARS-CoV-2 ORF1, whereas only COVID-19 patient antibodies primarily recognized spike protein and nucleoprotein. A machine learning model trained on VirScan data predicted SARS-CoV-2 exposure history with 99% sensitivity and 98% specificity; a rapid Luminex-based diagnostic was developed from the most discriminatory SARS-CoV-2 peptides. Individuals with more severe COVID-19 exhibited stronger and broader SARS-CoV-2 responses, weaker antibody responses to prior infections, and higher incidence of cytomegalovirus and herpes simplex virus 1, possibly influenced by demographic covariates. Among hospitalized patients, males produce stronger SARS-CoV-2 antibody responses than females.


Assuntos
COVID-19/imunologia , Mapeamento de Epitopos , Epitopos/imunologia , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Formação de Anticorpos , COVID-19/sangue , Teste Sorológico para COVID-19 , Reações Cruzadas , Microscopia Crioeletrônica , Epitopos/química , Epitopos/genética , Feminino , Humanos , Masculino , Conformação Proteica , Soroconversão
15.
Science ; 369(6505): 806-811, 2020 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-32434945

RESUMO

The global coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made the development of a vaccine a top biomedical priority. In this study, we developed a series of DNA vaccine candidates expressing different forms of the SARS-CoV-2 spike (S) protein and evaluated them in 35 rhesus macaques. Vaccinated animals developed humoral and cellular immune responses, including neutralizing antibody titers at levels comparable to those found in convalescent humans and macaques infected with SARS-CoV-2. After vaccination, all animals were challenged with SARS-CoV-2, and the vaccine encoding the full-length S protein resulted in >3.1 and >3.7 log10 reductions in median viral loads in bronchoalveolar lavage and nasal mucosa, respectively, as compared with viral loads in sham controls. Vaccine-elicited neutralizing antibody titers correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate vaccine protection against SARS-CoV-2 in nonhuman primates.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/prevenção & controle , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas de DNA/imunologia , Vacinas Virais/imunologia , Adjuvantes Imunológicos , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Betacoronavirus/fisiologia , Líquido da Lavagem Broncoalveolar/virologia , COVID-19 , Vacinas contra COVID-19 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Modelos Animais de Doenças , Feminino , Humanos , Imunidade Celular , Imunidade Humoral , Imunização Secundária , Imunogenicidade da Vacina , Memória Imunológica , Macaca mulatta , Masculino , Proteínas Mutantes/química , Proteínas Mutantes/imunologia , Mucosa Nasal/virologia , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Domínios Proteicos , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/genética , Vacinação , Vacinas de DNA/administração & dosagem , Carga Viral , Vacinas Virais/administração & dosagem
16.
Nat Microbiol ; 4(1): 187-197, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30455470

RESUMO

Eastern equine encephalitis virus (EEEV) is a mosquito-transmitted alphavirus with a high case mortality rate in humans. EEEV is a biodefence concern because of its potential for aerosol spread and the lack of existing countermeasures. Here, we identify a panel of 18 neutralizing murine monoclonal antibodies (mAbs) against the EEEV E2 glycoprotein, several of which have 'elite' activity with 50 and 99% effective inhibitory concentrations (EC50 and EC99) of less than 10 and 100 ng ml-1, respectively. Alanine-scanning mutagenesis and neutralization escape mapping analysis revealed epitopes for these mAbs in domains A or B of the E2 glycoprotein. A majority of the neutralizing mAbs blocked infection at a post-attachment stage, with several inhibiting viral membrane fusion. Administration of one dose of anti-EEEV mAb protected mice from lethal subcutaneous or aerosol challenge. These experiments define the mechanistic basis for neutralization by protective anti-EEEV mAbs and suggest a path forward for treatment and vaccine design.


Assuntos
Anticorpos Monoclonais/imunologia , Vírus da Encefalite Equina do Leste/imunologia , Encefalomielite Equina/imunologia , Encefalomielite Equina/prevenção & controle , Proteínas do Envelope Viral/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Chlorocebus aethiops , Cricetinae , Encefalomielite Equina/virologia , Mapeamento de Epitopos , Epitopos/imunologia , Feminino , Células HEK293 , Humanos , Camundongos , Domínios Proteicos/imunologia , Células Vero
17.
Vaccine ; 30(12): 2178-86, 2012 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-22285270

RESUMO

To circumvent limitations of poor antigen presentation and immunogenicity of DNA vaccines that target induction of CD8(+) T cell immunity, we have generated single chain MHC I trimers (MHC I SCTs) composed of a single polypeptide chain with a linear composition of antigenic peptide, ß2-microglobulin, and heavy chain of a MHC class I molecule connected by flexible linkers. Because of its pre-assembled nature, the SCT presents enhanced expression and presentation of the antigenic peptide/MHC complexes at the cell surface. Furthermore, DNA vaccination with a plasmid DNA encoding an SCT incorporating an immunodominant viral epitope elicited protective CD8(+) T cell responses against lethal virus infection. To extend these findings, here we tested the efficacy of SCT DNA vaccines against bacterial infections. In a mouse infection model of Listeria monocytogenes, the SCT DNA vaccine encoding H-2K(d) and the immunodominant peptide LLO 91-99 generated functional primary and memory peptide-specific CD8(+) T cells that confer partial protection against L. monocytogenes infection. DNA immunization of K(d)/LLO(91-99) SCTs generated functional memory CD8(+) T cells independently of CD4(+) T cells, although the expression of cognate or non-cognate CD4(+) helper T cell epitopes further enhanced the protective efficacy of SCTs. Our study further demonstrates that the SCT serves as a potent platform for DNA vaccines against various infectious diseases.


Assuntos
Antígenos de Bactérias/imunologia , Epitopos de Linfócito T/imunologia , Antígenos de Histocompatibilidade Classe I/imunologia , Listeria monocytogenes/imunologia , Listeriose/prevenção & controle , Vacinas de DNA/imunologia , Microglobulina beta-2/imunologia , Animais , Antígenos de Bactérias/genética , Antígenos CD/análise , Carga Bacteriana , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , ELISPOT , Epitopos de Linfócito T/genética , Citometria de Fluxo , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Epitopos Imunodominantes/genética , Epitopos Imunodominantes/imunologia , Interferon gama/metabolismo , Leucócitos Mononucleares/imunologia , Listeriose/imunologia , Fígado/microbiologia , Subpopulações de Linfócitos/química , Subpopulações de Linfócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Plasmídeos , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Baço/imunologia , Baço/microbiologia , Vacinas de DNA/administração & dosagem , Microglobulina beta-2/genética
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