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1.
Viruses ; 13(6)2021 06 14.
Artigo em Inglês | MEDLINE | ID: mdl-34198719

RESUMO

Humoral immunity has emerged as a vital immune component against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Nevertheless, a subset of recovered Coronavirus Disease-2019 (COVID-19) paucisymptomatic/asymptomatic individuals do not generate an antibody response, constituting a paradox. We assumed that immunodiagnostic assays may operate under a competitive format within the context of antigenemia, potentially explaining this phenomenon. We present a case where persistent antigenemia/viremia was documented for at least 73 days post-symptom onset using 'in-house' methodology, and as it progressively declined, seroconversion took place late, around day 55, supporting our hypothesis. Thus, prolonged SARS-CoV-2 antigenemia/viremia could mask humoral responses, rendering, in certain cases, the phenomenon of 'non-responders' a misnomer.


Assuntos
Anticorpos Antivirais/sangue , Antígenos Virais/sangue , Antígenos Virais/imunologia , Teste Sorológico para COVID-19/normas , COVID-19/diagnóstico , SARS-CoV-2/imunologia , Anticorpos Antivirais/metabolismo , Antígenos Virais/metabolismo , Sítios de Ligação de Anticorpos , COVID-19/sangue , COVID-19/imunologia , COVID-19/virologia , Teste Sorológico para COVID-19/estatística & dados numéricos , Humanos , Imunidade Humoral/imunologia , Imunoglobulina G/sangue , Masculino , Sensibilidade e Especificidade , Soroconversão , Adulto Jovem
2.
Mikrochim Acta ; 188(8): 262, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34282508

RESUMO

COVID-19 is now a severe threat to global health. Facing this pandemic, we developed a space-encoding microfluidic biochip for high-throughput, rapid, sensitive, simultaneous quantitative detection of SARS-CoV-2 antigen proteins and IgG/IgM antibodies in serum. The proposed immunoassay biochip integrates the advantages of graphene oxide quantum dots (GOQDs) and microfluidic chip and is capable of conducting multiple SARS-CoV-2 antigens or IgG/IgM antibodies of 60 serum samples simultaneously with only 2 µL sample volume of each patient. Fluorescence intensity of antigens and IgG antibody detection at emission wavelength of ~680 nm was used to quantify the target concentration at excitation wavelength of 632 nm, and emission wavelength of ~519 nm was used during the detection of IgM antibodies at excitation wavelength of 488 nm. The method developed has a large linear quantification detection regime of 5 orders of magnitude, an ultralow detection limit of ~0.3 pg/mL under optimized conditions, and less than 10-min qualitative detection time. The proposed biosensing platform will not only greatly facilitate the rapid diagnosis of COVID-19 patients, but also provide a valuable screening approach for infected patients, medical therapy, and vaccine recipients.


Assuntos
Antígenos Virais/sangue , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina M/sangue , SARS-CoV-2/isolamento & purificação , Reações Antígeno-Anticorpo , Antígenos Virais/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Nanopartículas/química , Tamanho da Partícula , SARS-CoV-2/imunologia , Sensibilidade e Especificidade
3.
Bull Exp Biol Med ; 171(2): 230-233, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-34173107

RESUMO

The presence of IgG and IgM antibodies in the venous blood of 76 patients with confirmed COVID-19 infection was determined by ELISA using Russian test systems. Different levels of IgM antibodies to N-protein and receptor binding domain of the Spike protein (RBD) were revealed. The dynamics of IgG antibodies to the whole virion antigen and recombinant antigens showed high values on weeks 4-5 of the disease. The level of IgG antibodies to Nprotein remained low throughout the observation period. The characteristic dynamics of IgG measured using test systems with sorbed whole virion or recombinant spike proteins reflects the duration of the disease.


Assuntos
Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , COVID-19/diagnóstico , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Glicoproteína da Espícula de Coronavírus/imunologia , Antígenos Virais/genética , COVID-19/sangue , COVID-19/imunologia , COVID-19/virologia , Proteínas do Nucleocapsídeo de Coronavírus/genética , Ensaio de Imunoadsorção Enzimática , Humanos , Imunidade Humoral , SARS-CoV-2/imunologia , SARS-CoV-2/patogenicidade , Glicoproteína da Espícula de Coronavírus/genética , Fatores de Tempo , Vírion/genética , Vírion/imunologia
4.
Cell Rep ; 35(13): 109305, 2021 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-34166618

RESUMO

The human leukocyte antigen (HLA)-bound viral antigens serve as an immunological signature that can be selectively recognized by T cells. As viruses evolve by acquiring mutations, it is essential to identify a range of presented viral antigens. Using HLA peptidomics, we are able to identify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-derived peptides presented by highly prevalent HLA class I (HLA-I) molecules by using infected cells as well as overexpression of SARS-CoV-2 genes. We find 26 HLA-I peptides and 36 HLA class II (HLA-II) peptides. Among the identified peptides, some are shared between different cells and some are derived from out-of-frame open reading frames (ORFs). Seven of these peptides were previously shown to be immunogenic, and we identify two additional immunoreactive peptides by using HLA multimer staining. These results may aid the development of the next generation of SARS-CoV-2 vaccines based on presented viral-specific antigens that span several of the viral genes.


Assuntos
Antígenos Virais/imunologia , COVID-19/imunologia , COVID-19/virologia , Peptídeos/imunologia , SARS-CoV-2/imunologia , Apresentação do Antígeno , Antígenos Virais/metabolismo , Vacinas contra COVID-19 , Linhagem Celular , Epitopos de Linfócito T/imunologia , Células HEK293 , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Peptidomiméticos , SARS-CoV-2/genética , Linfócitos T
5.
Hum Immunol ; 82(8): 551-560, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34116863

RESUMO

Given the highly polymorphic nature of Human Leukocyte Antigen (HLA) molecules, it is not surprising that they function as key regulators of the host immune response to almost all invading pathogens, including SARS-CoV-2, the etiological agent responsible for the recent COVID-19 pandemic. Several correlations have already been established between the expression of a specific HLA allele/haplotype and susceptibility/progression of SARS-CoV-2 infection and new ones are continuously emerging. Protective and harmful HLA variants have been described in both mild and severe forms of the disease, but considering the huge amount of existing variants, the data gathered in such a brief span of time are to some extent confusing and contradictory. The aim of this mini-review is to provide a snap-shot of the main findings so far collected on the HLA-SARS-CoV-2 interaction, so as to partially untangle this intricate yarn. As key factors in the generation of antigenic peptides to be presented by HLA molecules, ERAP1 and ERAP2 role in SARS-CoV-2 infection will be revised as well.


Assuntos
Aminopeptidases/genética , Apresentação do Antígeno , Antígenos Virais/imunologia , COVID-19/genética , Antígenos HLA/genética , Antígenos de Histocompatibilidade Menor/genética , Polimorfismo Genético , SARS-CoV-2/imunologia , Aminopeptidases/imunologia , Animais , COVID-19/diagnóstico , COVID-19/imunologia , COVID-19/virologia , Epitopos , Antígenos HLA/imunologia , Interações Hospedeiro-Patógeno , Humanos , Antígenos de Histocompatibilidade Menor/imunologia , SARS-CoV-2/patogenicidade
6.
Front Immunol ; 12: 635942, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34127926

RESUMO

SARS-CoV-2 infection takes a mild or clinically inapparent course in the majority of humans who contract this virus. After such individuals have cleared the virus, only the detection of SARS-CoV-2-specific immunological memory can reveal the exposure, and hopefully the establishment of immune protection. With most viral infections, the presence of specific serum antibodies has provided a reliable biomarker for the exposure to the virus of interest. SARS-CoV-2 infection, however, does not reliably induce a durable antibody response, especially in sub-clinically infected individuals. Consequently, it is plausible for a recently infected individual to yield a false negative result within only a few months after exposure. Immunodiagnostic attention has therefore shifted to studies of specific T cell memory to SARS-CoV-2. Most reports published so far agree that a T cell response is engaged during SARS-CoV-2 infection, but they also state that in 20-81% of SARS-CoV-2-unexposed individuals, T cells respond to SARS-CoV-2 antigens (mega peptide pools), allegedly due to T cell cross-reactivity with Common Cold coronaviruses (CCC), or other antigens. Here we show that, by introducing irrelevant mega peptide pools as negative controls to account for chance cross-reactivity, and by establishing the antigen dose-response characteristic of the T cells, one can clearly discern between cognate T cell memory induced by SARS-CoV-2 infection vs. cross-reactive T cell responses in individuals who have not been infected with SARS-CoV-2.


Assuntos
COVID-19/imunologia , COVID-19/virologia , Interações Hospedeiro-Patógeno/imunologia , SARS-CoV-2/imunologia , Linfócitos T/imunologia , Antígenos Virais/imunologia , Biomarcadores , COVID-19/metabolismo , Reações Cruzadas/imunologia , Citocinas/metabolismo , Epitopos de Linfócito T/imunologia , Humanos , Epitopos Imunodominantes/imunologia , Memória Imunológica , Peptídeos/imunologia , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/imunologia , Linfócitos T/metabolismo
7.
PLoS One ; 16(6): e0253321, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34166410

RESUMO

BACKGROUND: Antigen-detecting rapid diagnostic tests (Ag-RDTs) for the detection of SARS-CoV-2 offer new opportunities for testing in the context of the COVID-19 pandemic. Nasopharyngeal swabs (NPS) are the reference sample type, but oropharyngeal swabs (OPS) may be a more acceptable sample type in some patients. METHODS: We conducted a prospective study in a single screening center to assess the diagnostic performance of the Panbio™ COVID-19 Ag Rapid Test (Abbott) on OPS compared with reverse-transcription quantitative PCR (RT-qPCR) using NPS during the second pandemic wave in Switzerland. RESULTS: 402 outpatients were enrolled in a COVID-19 screening center, of whom 168 (41.8%) had a positive RT-qPCR test. The oropharyngeal Ag-RDT clinical sensitivity compared to nasopharyngeal RT-qPCR was 81% (95%CI: 74.2-86.6). Two false positives were noted out of the 234 RT-qPCR negative individuals, which resulted in a clinical specificity of 99.1% (95%CI: 96.9-99.9) for the Ag-RDT. For cycle threshold values ≤ 26.7 (≥ 1E6 SARS-CoV-2 genomes copies/mL, a presumed cut-off for infectious virus), 96.3% sensitivity (95%CI: 90.7-99.0%) was obtained with the Ag-RDT using OPS. INTERPRETATION: Based on our findings, the diagnostic performance of the Panbio™ Covid-19 RDT with OPS samples, if taken by a trained person and high requirements regarding quality of the specimen, meet the criteria required by the WHO for Ag-RDTs (sensitivity ≥80% and specificity ≥97%) in a high incidence setting in symptomatic individuals.


Assuntos
Antígenos Virais/imunologia , Teste Sorológico para COVID-19 , COVID-19 , Nasofaringe , SARS-CoV-2 , Antígenos Virais/genética , COVID-19/diagnóstico , COVID-19/epidemiologia , COVID-19/genética , COVID-19/imunologia , Teste de Ácido Nucleico para COVID-19 , Humanos , Nasofaringe/imunologia , Nasofaringe/virologia , Estudos Prospectivos , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Suíça/epidemiologia
8.
Int J Biol Macromol ; 183: 2162-2173, 2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34102236

RESUMO

Effective controls on viral infections rely on the continuous development in vaccine technology. Nanoparticle (NP) antigens are highly immunogenic based on their unique physicochemical properties, making them molecular scaffolds to present soluble vaccine antigens. Here, viral targets (113-354 aas) were genetically fused to N terminal of mi3, a protein that self-assembles into nanoparticles composed of 60 subunits. With transmission electron microscopy, it was confirmed that target-mi3 fusion proteins which have insertions of up to 354 aas in N terminal form intact NPs. Moreover, viral targets are surface-displayed on NPs as indicated in dynamic light scattering. NPs exhibit perfect stability after long-term storage at room temperature. Moreover, SP-E2-mi3 NPs enhance antigen uptake and maturation in dendritic cells (DCs) via up-regulating marker molecules and immunostimulatory cytokines. Importantly, in a mouse model, SP-E2-mi3 nanovaccines against Classical swine fever virus (CSFV) remarkably improved CSFV-specific neutralizing antibodies (NAbs) and cellular immunity related cytokines (IFN-γ and IL-4) as compared to monomeric E2. Specially, improved NAb response with more than tenfold increase in NAb titer against both CSFV Shimen and HZ-08 strains indicated better cross-protection against different genotypes. Collectively, this structure-based, self-assembling NP provides an attractive platform to improve the potency of subunit vaccine for emerging pathogens.


Assuntos
Antígenos Virais/farmacologia , Vírus da Febre Suína Clássica/imunologia , Peste Suína Clássica/prevenção & controle , Imunogenicidade da Vacina , Nanopartículas , Vacinas Virais/farmacologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Antígenos Virais/genética , Antígenos Virais/imunologia , Células Cultivadas , Peste Suína Clássica/sangue , Peste Suína Clássica/imunologia , Peste Suína Clássica/virologia , Citocinas/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Modelos Animais de Doenças , Estabilidade de Medicamentos , Feminino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/farmacologia , Suínos , Temperatura , Vacinas de Subunidades/imunologia , Vacinas de Subunidades/farmacologia , Vacinas Sintéticas/imunologia , Vacinas Sintéticas/farmacologia , Vacinas Virais/imunologia
9.
Viruses ; 13(5)2021 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-34068703

RESUMO

The virological meaning of the different patterns of serology in COVID-19 has been little examined in clinical settings. Asymptomatic subjects with IgM-spike (S) and IgG-nucleocapsid (N) determinations by chemiluminescence were studied for SARS-CoV-2 shedding in respiratory secretions by transcription-mediated amplification (TMA). In subjects showing IgM-S positive and IgG-N negative, IgG-S was determined by lateral flow assay. A total of 712 individuals were tested: 30.0% presented IgM-S(+)/IgG-N(-), 25.8% had IgM-S(+)/IgG-N(+) and 44.2% had IgM-S(-)/IgG-N(+); the proportion with TMA(+) were comparable in these three groups: 12.1, 8.7 and 10.5%, respectively. In individuals with IgM-S(+)/IgG-N(-), IgG-S(+) was detected in 66.5%. The frequency of IgM-S(+)/IgG-S(-) in the total population was 10.0%, of whom 24.1% had TMA(+); the chances for TMA(+) in subjects with an IgM-S(+) alone pattern were 2.4%. Targeting of the same SARS-CoV-2 antigen seems to be better for the characterization of IgM/IgG patterns of response. IgM-S(+) alone reactivity is rare, and a small proportion is associated with viral shedding.


Assuntos
Anticorpos Antivirais/sangue , COVID-19/imunologia , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Antígenos Virais/imunologia , COVID-19/diagnóstico , Teste Sorológico para COVID-19 , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Nasofaringe/virologia , Fosfoproteínas/imunologia , Sensibilidade e Especificidade
10.
Viruses ; 13(5)2021 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-34068899

RESUMO

The use of rapid antigenic tests (Ag-RDTs) to diagnose a SARS-CoV-2 infection has become a common practice recently. This study aimed to evaluate performance of Abbott PanbioTM Ag-RDTs with regard to nucleic acid amplification testing (NAAT) in the early stages of the disease. A cohort of 149,026 infected symptomatic patients, reported in Catalonia from November 2020 to January 2021, was selected. The positivity rates of the two tests were compared with respect to the dates of symptom onset. Ag-RDTs presented positivity rates of 84% in the transmission phases of the disease and 31% in the pre-symptomatic period, compared to 93% and 91%, respectively, for NAAT. The detection of many false negatives with Ag-RDTs during the pre-symptomatic period demonstrates the risk of virus dissemination with this diagnostic technique if used outside the symptomatic period.


Assuntos
Teste de Ácido Nucleico para COVID-19/métodos , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos Virais/imunologia , Doenças Assintomáticas , Criança , Pré-Escolar , Estudos de Coortes , Reações Falso-Negativas , Reações Falso-Positivas , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Técnicas de Amplificação de Ácido Nucleico/métodos , Sensibilidade e Especificidade , Espanha , Adulto Jovem
11.
mBio ; 12(3)2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-34006662

RESUMO

The ongoing coronavirus disease 2019 (COVID-19) pandemic has seen an unprecedented increase in the demand for rapid and reliable diagnostic tools, leaving many laboratories scrambling for resources. We present a fast and simple assay principle for antigen detection and demonstrate its functionality by detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in nasopharyngeal swabs. The method is based on the detection of SARS-CoV-2 nucleoprotein (NP) and S protein (SP) via time-resolved Förster resonance energy transfer (TR-FRET) with donor- and acceptor-labeled polyclonal anti-NP and -SP antibodies. Using recombinant proteins and cell culture-grown SARS-CoV-2, the limits of detection were established as 25 pg of NP or 20 infectious units (IU) and 875 pg of SP or 625 IU. Testing reverse transcription-PCR (RT-PCR)-positive (n = 48, with cycle threshold [CT ] values from 11 to 30) or -negative (n = 96) nasopharyngeal swabs demonstrated that the assay yielded positive results for all samples with CT values of <25 and for a single RT-PCR-negative sample. Virus isolation from the RT-PCR-positive nasopharyngeal swabs showed a strong association between the presence of infectious virus and a positive antigen test result. The NP-based assay showed 97.4% (37/38) sensitivity and 100% (10/10) specificity in comparison with virus isolation and 77.1% (37/48) sensitivity and 99.0% (95/96) specificity in comparison with SARS-CoV-2 RT-PCR. The assay is performed in a buffer that neutralizes SARS-CoV-2 infectivity, and the assay is relatively simple to set up as an "in-house" test. Here, SARS-CoV-2 served as the model pathogen, but the assay principle is applicable to other viral infections, and the test format could easily be adapted to high-throughput testing.IMPORTANCE PCR is currently the gold standard for the diagnosis of many acute infections. While PCR and its variants are highly sensitive and specific, the time from sampling to results is measured in hours at best. Antigen tests directly detect parts of the infectious agent, which may enable faster diagnosis but often at lower sensitivity and specificity. Here, we describe a technique for rapid antigen detection and demonstrate the test format's potential using SARS-CoV-2 as the model pathogen. The 10-min test, performed in a buffer that readily inactivates SARS-CoV-2, from nasopharyngeal samples identified 97.4% (37/38) of the samples from which we could isolate the virus. This suggests that the test performs well in identifying patients potentially shedding the virus. Although SARS-CoV-2 served as the model pathogen to demonstrate proof of concept, the test principle itself would be applicable to a wide variety of infectious and perhaps also noninfectious diseases.


Assuntos
Antígenos Virais/análise , Teste Sorológico para COVID-19/métodos , Transferência Ressonante de Energia de Fluorescência , SARS-CoV-2/isolamento & purificação , Antígenos Virais/imunologia , COVID-19/diagnóstico , COVID-19/virologia , Proteínas do Nucleocapsídeo de Coronavírus/análise , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Humanos , Limite de Detecção , Nasofaringe/virologia , Fosfoproteínas/análise , Fosfoproteínas/imunologia , Estudo de Prova de Conceito , Proteínas Recombinantes/imunologia , SARS-CoV-2/imunologia , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/análise , Glicoproteína da Espícula de Coronavírus/imunologia , Fatores de Tempo
12.
J Immunol ; 206(10): 2393-2401, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33941657

RESUMO

Serological tests for detection of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Abs in blood are expected to identify individuals who have acquired immunity against SARS-CoV-2 and indication of seroprevalence of SARS-CoV-2 infection. Many serological tests have been developed to detect Abs against SARS-CoV-2. However, these tests have considerable variations in their specificity and sensitivity, and whether they can predict levels of neutralizing activity is yet to be determined. This study aimed to investigate the kinetics and neutralizing activity of various Ag-specific Ab isotypes against SARS-CoV-2 in serum of coronavirus disease 2019 (COVID-19) patients confirmed via PCR test. We developed IgG, IgM, and IgA measurement assays for each Ag, including receptor-binding domain (RBD) of spike (S) protein, S1 domain, full-length S protein, S trimer, and nucleocapsid (N) domain, based on ELISA. The assays of the S protein for all isotypes showed high specificity, whereas the assays for all isotypes against N protein showed lower specificity. The sensitivity of all Ag-specific Ab isotypes depended on the timing of the serum collection and all of them, except for IgM against N protein, reached more than 90% at 15-21 d postsymptom onset. The best correlation with virus-neutralizing activity was found for IgG against RBD, and levels of IgG against RBD in sera from four patients with severe COVID-19 increased concordantly with neutralizing activity. Our results provide valuable information regarding the selection of serological test for seroprevalence and vaccine evaluation studies.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Especificidade de Anticorpos , Antígenos Virais/imunologia , COVID-19/imunologia , Isotipos de Imunoglobulinas/imunologia , SARS-CoV-2/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/diagnóstico , Teste de Ácido Nucleico para COVID-19 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
13.
J Biol Chem ; 296: 100745, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33957119

RESUMO

Fifty years ago, the first landmark structures of antibodies heralded the dawn of structural immunology. Momentum then started to build toward understanding how antibodies could recognize the vast universe of potential antigens and how antibody-combining sites could be tailored to engage antigens with high specificity and affinity through recombination of germline genes (V, D, J) and somatic mutation. Equivalent groundbreaking structures in the cellular immune system appeared some 15 to 20 years later and illustrated how processed protein antigens in the form of peptides are presented by MHC molecules to T cell receptors. Structures of antigen receptors in the innate immune system then explained their inherent specificity for particular microbial antigens including lipids, carbohydrates, nucleic acids, small molecules, and specific proteins. These two sides of the immune system act immediately (innate) to particular microbial antigens or evolve (adaptive) to attain high specificity and affinity to a much wider range of antigens. We also include examples of other key receptors in the immune system (cytokine receptors) that regulate immunity and inflammation. Furthermore, these antigen receptors use a limited set of protein folds to accomplish their various immunological roles. The other main players are the antigens themselves. We focus on surface glycoproteins in enveloped viruses including SARS-CoV-2 that enable entry and egress into host cells and are targets for the antibody response. This review covers what we have learned over the past half century about the structural basis of the immune response to microbial pathogens and how that information can be utilized to design vaccines and therapeutics.


Assuntos
Imunidade Adaptativa , Anticorpos Antivirais/química , Antígenos Virais/química , Imunidade Inata , Receptores de Antígenos de Linfócitos T/química , Receptores de Citocinas/química , SARS-CoV-2/imunologia , Alergia e Imunologia/história , Animais , Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Especificidade de Anticorpos , Apresentação do Antígeno , Antígenos Virais/genética , Antígenos Virais/imunologia , COVID-19/imunologia , COVID-19/virologia , Cristalografia/história , Cristalografia/métodos , História do Século XX , História do Século XXI , Humanos , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Citocinas/genética , Receptores de Citocinas/imunologia , SARS-CoV-2/patogenicidade , Recombinação V(D)J
14.
J Infect Dis ; 224(2): 241-245, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-33961690

RESUMO

We investigated the duration of humoral and T-cell immune response in paired samples among 22 convalescent healthcare workers (HCWs). A median of 1.8 months after diagnosis, T-cell response was significantly lower in HCWs with early loss of antibodies (6 cases [27%]). After 5.1 months, antibody decline was observed in 77% of cases (41% seroreverted; P < .01), and 36% had lost T-cell response (75% lost response to spike protein). Persistence of immune response was observed in those who developed a greater adaptive immune response. Our data point to the initial immune response as the relevant player in coronavirus disease 2019 duration of protection.


Assuntos
COVID-19/imunologia , Convalescença , Pessoal de Saúde/estatística & dados numéricos , Imunidade Humoral , Linfócitos T/imunologia , Imunidade Adaptativa , Adulto , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Citocinas/imunologia , Feminino , Seguimentos , Humanos , Interferon gama/imunologia , Masculino , Pessoa de Meia-Idade , SARS-CoV-2/imunologia
15.
Int J Infect Dis ; 107: 271-277, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33991681

RESUMO

OBJECTIVES: This study aimed to evaluate a microfluidic paper-based analytical device (DEN-NS1-PAD) based on a rapid NS1 antigen test for diagnosing dengue at the point of care. METHODS: 219 serum samples from suspected dengue cases were tested with the developed DEN-NS1-PAD and commercial RDT by SD BIOLINE. The results were compared with the nested-PCR results. RESULTS: The limit of detection of DEN-NS1-PAD was 0.78 ng mL-1. It showed 88.89% sensitivity, 86.67% specificity, and a substantial agreement correlation (κ = 0.7522) compared with nested-PCR. In contrast, SD BIOLINE for NS1 (SD-NS1) detection showed 87.88% sensitivity, 90.00% specificity, and had a substantial agreement correlation with nested-PCR (κ = 0.7788). CONCLUSIONS: DEN-NS1-PAD is a valuable tool for diagnosing DENV infections, especially for diagnosed patients with early acute phase samples with high viral load. DEN-NS1-PAD has better sensitivity than SD-NS1 but less specificity.


Assuntos
Antígenos Virais/análise , Vírus da Dengue/imunologia , Febre/diagnóstico , Febre/virologia , Papel , Testes Imediatos , Antígenos Virais/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Tempo
17.
Nucleic Acids Res ; 49(W1): W671-W678, 2021 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-34009334

RESUMO

Vaccination is one of the most significant inventions in medicine. Reverse vaccinology (RV) is a state-of-the-art technique to predict vaccine candidates from pathogen's genome(s). To promote vaccine development, we updated Vaxign2, the first web-based vaccine design program using reverse vaccinology with machine learning. Vaxign2 is a comprehensive web server for rational vaccine design, consisting of predictive and computational workflow components. The predictive part includes the original Vaxign filtering-based method and a new machine learning-based method, Vaxign-ML. The benchmarking results using a validation dataset showed that Vaxign-ML had superior prediction performance compared to other RV tools. Besides the prediction component, Vaxign2 implemented various post-prediction analyses to significantly enhance users' capability to refine the prediction results based on different vaccine design rationales and considerably reduce user time to analyze the Vaxign/Vaxign-ML prediction results. Users provide proteome sequences as input data, select candidates based on Vaxign outputs and Vaxign-ML scores, and perform post-prediction analysis. Vaxign2 also includes precomputed results from approximately 1 million proteins in 398 proteomes of 36 pathogens. As a demonstration, Vaxign2 was used to effectively analyse SARS-CoV-2, the coronavirus causing COVID-19. The comprehensive framework of Vaxign2 can support better and more rational vaccine design. Vaxign2 is publicly accessible at http://www.violinet.org/vaxign2.


Assuntos
Desenho de Fármacos , Internet , Aprendizado de Máquina , Software , Vacinas , Vacinologia/métodos , Antígenos Virais/química , Antígenos Virais/imunologia , COVID-19/virologia , Vacinas contra COVID-19/química , Vacinas contra COVID-19/imunologia , Epitopos/química , Epitopos/imunologia , Humanos , Proteoma , SARS-CoV-2/química , SARS-CoV-2/imunologia , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/imunologia , Vacinas/química , Vacinas/imunologia , Fluxo de Trabalho
18.
Proc Natl Acad Sci U S A ; 118(20)2021 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-33947795

RESUMO

The urgency for the development of a sensitive, specific, and rapid point-of-care diagnostic test has deepened during the ongoing COVID-19 pandemic. Here, we introduce an ultrasensitive chip-based antigen test with single protein biomarker sensitivity for the differentiated detection of both severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A antigens in nasopharyngeal swab samples at diagnostically relevant concentrations. The single-antigen assay is enabled by synthesizing a brightly fluorescent reporter probe, which is incorporated into a bead-based solid-phase extraction assay centered on an antibody sandwich protocol for the capture of target antigens. After optimization of the probe release for detection using ultraviolet light, the full assay is validated with both SARS-CoV-2 and influenza A antigens from clinical nasopharyngeal swab samples (PCR-negative spiked with target antigens). Spectrally multiplexed detection of both targets is implemented by multispot excitation on a multimode interference waveguide platform, and detection at 30 ng/mL with single-antigen sensitivity is reported.


Assuntos
Antígenos Virais/isolamento & purificação , Vírus da Influenza A/isolamento & purificação , Técnicas Analíticas Microfluídicas/métodos , Técnicas de Diagnóstico Molecular/métodos , SARS-CoV-2/isolamento & purificação , Antígenos Virais/imunologia , Técnicas Biossensoriais , COVID-19/diagnóstico , Fluorescência , Humanos , Vírus da Influenza A/imunologia , Influenza Humana/diagnóstico , Dispositivos Lab-On-A-Chip , Limite de Detecção , Nasofaringe/virologia , Sistemas Automatizados de Assistência Junto ao Leito , SARS-CoV-2/imunologia
19.
J Autoimmun ; 121: 102663, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34020254

RESUMO

As the novel SARS-CoV-2 continues to infect numerous individuals worldwide, one of the leading approaches in dealing with the global health crisis is vaccination against the COVID-19. Due to recent reports, vaccination with ChAdOx1 nCov-19 (developed by Oxford and AstraZeneca) may result in a vaccine-induced catastrophic thrombotic thrombocytopenia disorder. Thus, as of March 16 of 2021, vaccination programs in 18 countries had been suspended until further examination, including Sweden, Germany and France. This disorder presents as extensive thrombosis in atypical sites, primarily in the cerebral venous, alongside thrombocytopenia and the production of autoantibody against platelet-factor 4 (PF4). PF4 autoantibody has the ability to binds the human FcRγIIA receptor of platelets and contribute to their aggregation. This rare adverse effect extremely resembles the clinical presentation of the classical immune-mediated HIT disorder, which occurs following exposure to heparin. Surprisingly, none of these patients had been pre-exposed to heparin before disease onset, leading to the hypothesis that a viral antigen from the vaccine had triggered the response. Importantly, COVID-19 had been associated with numerous autoimmune manifestations, including the production of pathogenic autoantibodies, new onset of autoimmune diseases and disorders. As the ChAdOx1 nCov-19 vaccination leads to the synthesis of specific SARS-CoV-2-proteins, they may trigger a production of PF4 autoantibody though molecular mimicry phenomena, while vaccination compounds lead to a rigorous bystander activation of immune cells. If existing, removing such homological sequences from the vaccine may eliminate this phenomenon. In contrast, it needs to be emphasized that the ChAdOx1 nCoV-19 vaccine was found to be safe and efficacious against symptomatic COVID-19 in randomized controlled trials, which included 23,848 participants from the UK, Brazil and South Africa.


Assuntos
Vacinas contra COVID-19/efeitos adversos , COVID-19/imunologia , Púrpura Trombocitopênica Idiopática/imunologia , SARS-CoV-2/imunologia , Antígenos Virais/imunologia , Autoanticorpos/imunologia , COVID-19/patologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Vacinas contra COVID-19/uso terapêutico , Humanos , Fator Plaquetário 4/imunologia , Púrpura Trombocitopênica Idiopática/induzido quimicamente , Púrpura Trombocitopênica Idiopática/patologia
20.
Nat Commun ; 12(1): 2633, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976149

RESUMO

Ebola virus (EBOV) glycoprotein (GP) can be recognized by neutralizing antibodies (NAbs) and is the main target for vaccine design. Here, we first investigate the contribution of the stalk and heptad repeat 1-C (HR1C) regions to GP metastability. Specific stalk and HR1C modifications in a mucin-deleted form (GPΔmuc) increase trimer yield, whereas alterations of HR1C exert a more complex effect on thermostability. Crystal structures are determined to validate two rationally designed GPΔmuc trimers in their unliganded state. We then display a modified GPΔmuc trimer on reengineered protein nanoparticles that encapsulate a layer of locking domains (LD) and a cluster of helper T-cell epitopes. In mice and rabbits, GP trimers and nanoparticles elicit cross-ebolavirus NAbs, as well as non-NAbs that enhance pseudovirus infection. Repertoire sequencing reveals quantitative profiles of vaccine-induced B-cell responses. This study demonstrates a promising vaccine strategy for filoviruses, such as EBOV, based on GP stabilization and nanoparticle display.


Assuntos
Vacinas contra Ebola/administração & dosagem , Glicoproteínas/administração & dosagem , Doença pelo Vírus Ebola/terapia , Proteínas Virais/administração & dosagem , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Antígenos Virais/administração & dosagem , Antígenos Virais/genética , Antígenos Virais/imunologia , Antígenos Virais/ultraestrutura , Linfócitos B/imunologia , Cristalografia por Raios X , Modelos Animais de Doenças , Vacinas contra Ebola/genética , Vacinas contra Ebola/imunologia , Ebolavirus/genética , Ebolavirus/imunologia , Epitopos de Linfócito T/administração & dosagem , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Epitopos de Linfócito T/ultraestrutura , Feminino , Glicoproteínas/genética , Glicoproteínas/imunologia , Glicoproteínas/ultraestrutura , Doença pelo Vírus Ebola/sangue , Doença pelo Vírus Ebola/imunologia , Doença pelo Vírus Ebola/virologia , Humanos , Camundongos , Nanopartículas/química , Domínios Proteicos/genética , Domínios Proteicos/imunologia , Engenharia de Proteínas , Multimerização Proteica/genética , Multimerização Proteica/imunologia , Estabilidade Proteica , Coelhos , Linfócitos T Auxiliares-Indutores/imunologia , Vacinas de Subunidades/administração & dosagem , Vacinas de Subunidades/genética , Vacinas de Subunidades/imunologia , Proteínas Virais/genética , Proteínas Virais/imunologia , Proteínas Virais/ultraestrutura
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