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1.
Front Immunol ; 12: 635701, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34489923

RESUMO

Serological testing is a powerful tool in epidemiological studies for understanding viral circulation and assessing the effectiveness of virus control measures, as is the case of SARS-CoV-2, the pathogenic agent of COVID-19. Immunoassays can quantitatively reveal the concentration of antiviral antibodies. The assessment of antiviral antibody titers may provide information on virus exposure, and changes in IgG levels are also indicative of a reduction in viral circulation. In this work, we describe a serological study for the evaluation of antiviral IgG and IgM antibodies and their correlation with antiviral activity. The serological assay for IgG detection used two SARS-CoV-2 proteins as antigens, the nucleocapsid N protein and the 3CL protease. Cross-reactivity tests in animals have shown high selectivity for detection of antiviral antibodies, using both the N and 3CL antigens. Using samples of human serum from individuals previously diagnosed by PCR for COVID-19, we observed high sensitivity of the ELISA assay. Serological results with human samples also suggest that the combination of higher titers of antiviral IgG antibodies to different antigen targets may be associated with greater neutralization activity, which can be enhanced in the presence of antiviral IgM antibodies.


Assuntos
Anticorpos Antivirais/imunologia , Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , COVID-19/prevenção & controle , Vigilância Imunológica , SARS-CoV-2/imunologia , Animais , Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , COVID-19/epidemiologia , COVID-19/imunologia , Teste Sorológico para COVID-19/normas , Reações Cruzadas , Vírus da Dengue/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Ensaio de Imunoadsorção Enzimática/normas , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Camundongos , Camundongos Endogâmicos BALB C , Sensibilidade e Especificidade , Zika virus/imunologia
2.
Viruses ; 13(7)2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34372551

RESUMO

BACKGROUND: In 2015-2016, a large Zika virus (ZIKV) outbreak occurred in the Americas. Although the exact ZIKV antibody kinetics after infection are unknown, recent evidence indicates the rapid waning of ZIKV antibodies in humans. Therefore, we aimed to determine the levels of ZIKV antibodies more than three years after a ZIKV infection. METHODS: We performed ZIKV virus neutralization tests (VNT) and a commercial ZIKV non-structural protein 1 (NS1) IgG ELISA in a cohort of 49 participants from Suriname who had a polymerase-chain-reaction-confirmed ZIKV infection more than three years ago. Furthermore, we determined the presence of antibodies against multiple dengue virus (DENV) antigens. RESULTS: The ZIKV seroprevalence in this cohort, assessed with ZIKV VNT and ZIKV NS1 IgG ELISA, was 59.2% and 63.3%, respectively. There was, however, no correlation between these two tests. Furthermore, we did not find evidence of a potential negative influence of DENV immunity on ZIKV antibody titers. CONCLUSIONS: ZIKV seroprevalence, assessed with two commonly used serological tests, was lower than expected in this cohort of participants who had a confirmed previous ZIKV infection. This can have implications for future ZIKV seroprevalence studies and possibly for the duration of immunological protection after a ZIKV infection.


Assuntos
Anticorpos Neutralizantes/análise , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adulto , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/análise , Anticorpos Antivirais/imunologia , Estudos de Coortes , Reações Cruzadas/imunologia , Dengue/virologia , Vírus da Dengue/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Masculino , Pessoa de Meia-Idade , Testes de Neutralização/métodos , Estudos Soroepidemiológicos , Testes Sorológicos/métodos , Suriname , Zika virus/patogenicidade , Infecção por Zika virus/metabolismo , Infecção por Zika virus/virologia
3.
BMC Infect Dis ; 21(1): 704, 2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34303348

RESUMO

BACKGROUND: The co-circulation of types of arbovirus in areas where they are endemic increased the risk of outbreaks and limited the diagnostic methods available. Here, we analyze the epidemiological profile of DENV, CHIKV and ZIKV at the serological and molecular level in patients with suspected infection with these arboviruses in the city of Juazeiro do Norte, Ceará, Brazil. METHODS: In 2016, the Central Public Health Laboratory (LACEN) of Juazeiro do Norte received 182 plasma samples from patients who visited health facilities with symptoms compatible with arbovirus infection. The LACEN performed serological tests for detection of IgM/IgG to DENV and CHIKV. They then sent these samples to the Retrovirology Laboratory of the Federal University of São Paulo and Faculty of Medical of the ABC where molecular analyses to confirm the infection by DENV, ZIKV and CHIKV were performed. The prevalence of IgM/IgG antibodies and of infections confirmed by RT-qPCR were presented with 95% confidence interval. RESULTS: In serologic analysis, 125 samples were positive for antibodies against CHIKV and all were positive for antibodies against DENV. A higher prevalence of IgG against CHIKV (63.20% with 95% CI: 45.76-70.56) than against DENV (95.05% with 95% CI: 78.09-98.12) was observed. When the samples were submitted to analysis by RT-qPCR, we observed the following prevalence: mono-infection by ZIKV of 19.23% (95% CI: 14.29-34.82) patients, mono-infection by CHIKV of 3.84% (95% CI: 2.01-5.44) and co-infection with ZIKV and CHIKV of 1.09% (95% CI: 0.89-4.56). CONCLUSION: The serologic and molecular tests performed in this study were effective in analyzing the epidemiological profile of DENV, CHIKV and ZIKV in patients with suspected infection by these arboviruses in the city of Juazeiro do Norte, Ceará/Brazil.


Assuntos
Anticorpos Antivirais/sangue , Febre de Chikungunya/epidemiologia , Vírus Chikungunya/imunologia , Vírus da Dengue/imunologia , Dengue/epidemiologia , Infecção por Zika virus/epidemiologia , Zika virus/imunologia , Adulto , Brasil/epidemiologia , Febre de Chikungunya/terapia , Cidades/epidemiologia , Estudos Transversais , Dengue/terapia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Reação em Cadeia da Polimerase em Tempo Real , Medição de Risco , Testes Sorológicos , Infecção por Zika virus/terapia
4.
Nat Immunol ; 22(8): 958-968, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34267374

RESUMO

Antibody-dependent enhancement (ADE) is an important safety concern for vaccine development against dengue virus (DENV) and its antigenically related Zika virus (ZIKV) because vaccine may prime deleterious antibodies to enhance natural infections. Cross-reactive antibodies targeting the conserved fusion loop epitope (FLE) are known as the main sources of ADE. We design ZIKV immunogens engineered to change the FLE conformation but preserve neutralizing epitopes. Single vaccination conferred sterilizing immunity against ZIKV without ADE of DENV-serotype 1-4 infections and abrogated maternal-neonatal transmission in mice. Unlike the wild-type-based vaccine inducing predominately cross-reactive ADE-prone antibodies, B cell profiling revealed that the engineered vaccines switched immunodominance to dispersed patterns without DENV enhancement. The crystal structure of the engineered immunogen showed the dimeric conformation of the envelope protein with FLE disruption. We provide vaccine candidates that will prevent both ZIKV infection and infection-/vaccination-induced DENV ADE.


Assuntos
Anticorpos Facilitadores/imunologia , Antígenos Virais/imunologia , Reações Cruzadas/imunologia , Vacinas contra Dengue/imunologia , Dengue/prevenção & controle , Zika virus/imunologia , Aedes , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Linfócitos B/imunologia , Chlorocebus aethiops , Cricetinae , Vírus da Dengue/imunologia , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Receptor de Interferon alfa e beta/genética , Vacinação , Células Vero , Infecção por Zika virus/imunologia , Infecção por Zika virus/prevenção & controle
5.
BMC Infect Dis ; 21(1): 639, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215212

RESUMO

BACKGROUND: Infection by chikungunya (CHIKV) and dengue virus (DENV) can cause a wide spectrum of clinical features, many of which are undifferentiated. Cytokines, which broadly also include chemokines and growth factors, have been shown to play a role in protective immunity as well as DENV and CHIKV pathogenesis. However, differences in cytokine response to both viruses remain poorly understood, especially in patients from countries where both viruses are endemic. Our study is therefore aimed to provide a comparative profiling of cytokine response induced by acute DENV and CHIKV infections in patients with similar disease stages and in experimental in vitro infections. METHODS: By using multiplex immunoassay, we compared host cytokine profiles between acute CHIKV and DENV infections by analysing serum cytokine levels of IL-1α, IL-4, IL-5, IL-8, IL-13, RANTES, MCP-3, eotaxin, PDGF-AB/BB, and FGF-2 from the sera of acute chikungunya and dengue fever patients. We further investigated the cytokine profile responses using experimental in vitro CHIKV and DENV infections of peripheral blood mononuclear cells (PBMCs). RESULTS: We found that both CHIKV and DENV-infected patients had an upregulated level of IL-8 and IL-4, with the highest IL-4 level observed in DENV-2 infected patients. Higher IL-8 level was also correlated with lower platelet count in dengue patients. IL-13 and MCP-3 downregulation was observed only in chikungunya patients, while conversely PDGF-AB/BB and FGF-2 downregulation was unique in dengue patients. Age-associated differential expression of IL-13, MCP-3, and IL-5 was also observed, while distinct kinetics of IL-4, IL-8, and FGF-2 expression between CHIKV and DENV-infected patients were identified. Furthermore, the unique pattern of IL-8, IL-13 and MCP-3, but not IL-4 expression was also recapitulated using experimental in vitro infection in PBMCs. CONCLUSIONS: Taken together, our study identified common cytokine response profile characterized by upregulation of IL-8 and IL-4 between CHIKV and DENV infection. Downregulation of IL-13 and MCP-3 was identified as a unique cytokine response profile of acute CHIKV infection, while distinct downregulation of PDGF-AB/BB and FGF-2 characterized the response from acute DENV infection. Our study provides an important overview of the host cytokine responses between CHIKV and DENV infection, which is important to further understand the mechanism and pathology of these diseases.


Assuntos
Febre de Chikungunya/imunologia , Vírus Chikungunya/imunologia , Citocinas/metabolismo , Vírus da Dengue/imunologia , Dengue/imunologia , Adolescente , Adulto , Idoso , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/metabolismo , Febre de Chikungunya/virologia , Criança , Pré-Escolar , Estudos Transversais , Citocinas/imunologia , Dengue/epidemiologia , Dengue/metabolismo , Dengue/virologia , Feminino , Humanos , Indonésia/epidemiologia , Lactente , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Adulto Jovem
6.
Viruses ; 13(5)2021 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-34066286

RESUMO

Sub-neutralizing concentrations of antibodies in dengue infected patients is a major risk factor for the development of dengue hemorrhagic fever and dengue shock syndrome. Here, we describe a mouse model with a deficiency in mast cells (MCs) in addition to a deficiency in Type-I and II IFN receptors for studying dengue virus (DENV) infection. We used this model to understand the influence of MCs in a maternal antibody-dependent model of severe dengue, where offspring born to DENV-immune mothers are challenged with a heterologous DENV serotype. Mice lacking both MCs and IFN receptors were found susceptible to primary DENV infection and showed morbidity and mortality. When these mice were immunized, pups born to DENV-immune mothers were found to be protected for a longer duration from a heterologous DENV challenge. In the absence of MCs and type-I interferon signaling, IFN-γ was found to protect pups born to naïve mothers but had the opposite effect on pups born to DENV-immune mothers. Our results highlight the complex interactions between MCs and IFN-signaling in influencing the role of maternal antibodies in DENV-induced disease severity.


Assuntos
Imunidade Materno-Adquirida , Mastócitos/imunologia , Exposição Materna , Efeitos Tardios da Exposição Pré-Natal , Dengue Grave/diagnóstico , Dengue Grave/etiologia , Animais , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Vírus da Dengue/imunologia , Modelos Animais de Doenças , Suscetibilidade a Doenças , Feminino , Hospedeiro Imunocomprometido , Mastócitos/metabolismo , Camundongos , Camundongos Knockout , Gravidez , Receptor de Interferon alfa e beta/deficiência , Índice de Gravidade de Doença
7.
Science ; 372(6546): 1102-1105, 2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34083490

RESUMO

Although antiviral antibodies generally confer protective functions, antibodies against dengue virus (DENV) are associated with enhanced disease susceptibility. Antibodies can mediate DENV infection of leukocytes via Fcγ receptors, likely contributing to dengue disease pathogenesis. To determine if this mechanism accounts for variable disease severity, we examined Fab and Fc structures of anti-DENV antibodies from patients before and after infection and with variable disease outcomes. Neither antibody titers nor neutralizing activity correlated with disease severity in DENV-infected populations. Rather, DENV infection induced a specific increase in immunoglobulin G1 (IgG1) afucosylation, and the levels of afucosylated IgG1 were predictive of dengue disease severity. Thus, the IgG1 fucosylation status represents a robust prognostic tool for dengue disease, highlighting the key role of the Fc glycan structure in dengue pathogenesis.


Assuntos
Anticorpos Antivirais/sangue , Anticorpos Antivirais/química , Vírus da Dengue/imunologia , Dengue/imunologia , Fucose/análise , Dengue Grave/imunologia , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Anticorpos Facilitadores , Criança , Coinfecção/imunologia , Dengue/fisiopatologia , Feminino , Humanos , Fragmentos Fc das Imunoglobulinas/química , Fragmentos Fc das Imunoglobulinas/imunologia , Imunoglobulina G/sangue , Imunoglobulina G/química , Imunoglobulina G/imunologia , Masculino , Receptores de IgG/química , Receptores de IgG/imunologia , Dengue Grave/fisiopatologia , Índice de Gravidade de Doença , Infecção por Zika virus/imunologia
8.
Front Immunol ; 12: 629167, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34122402

RESUMO

Neutrophil extracellular traps (NETs) are increasingly recognized to play a role in the pathogenesis of viral infections, including dengue. NETs can be formed NADPH oxidase (NOX)-dependently or NOX-independently. NOX-independent NETs can be induced by activated platelets and are very potent in activating the endothelium. Platelet activation with thrombocytopenia and endothelial dysfunction are prominent features of dengue virus infection. We postulated that dengue infection is associated with NOX-independent NET formation, which is related to platelet activation, endothelial perturbation and increased vascular permeability. Using our specific NET assays, we investigated the time course of NET formation in a cohort of Indonesian dengue patients. We found that plasma levels of NETs were profoundly elevated and that these NETs were predominantly NOX-independent NETs. During early recovery phase (7-13 days from fever onset), total NETs correlated negatively with platelet number and positively with platelet P-selectin expression, the binding of von Willebrand factor to platelets and levels of Syndecan-1. Patients with gall bladder wall thickening, an early marker of plasma leakage, had a higher median level of total NETs. Ex vivo, platelets induced NOX-independent NET formation in a dengue virus non-structural protein 1 (NS1)-dependent manner. We conclude that NOX-independent NET formation is enhanced in dengue, which is most likely mediated by NS1 and activated platelets.


Assuntos
Plaquetas/metabolismo , Vírus da Dengue/patogenicidade , Dengue/enzimologia , Armadilhas Extracelulares/metabolismo , NADPH Oxidases/metabolismo , Neutrófilos/enzimologia , Ativação Plaquetária , Adolescente , Adulto , Plaquetas/imunologia , Plaquetas/virologia , Estudos de Casos e Controles , Células Cultivadas , Dengue/sangue , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/imunologia , Vírus da Dengue/metabolismo , Armadilhas Extracelulares/virologia , Feminino , Interações Hospedeiro-Patógeno , Humanos , Indonésia , Masculino , Neutrófilos/imunologia , Neutrófilos/virologia , Estudos Prospectivos , Proteínas não Estruturais Virais/metabolismo , Adulto Jovem
9.
Front Immunol ; 12: 599805, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34079535

RESUMO

Background: Dengue virus (DENV) infection has a global impact on public health. The clinical outcomes (of DENV) can vary from a flu-like illness called dengue fever (DF), to a more severe form, known as dengue hemorrhagic fever (DHF). The underlying innate immune mechanisms leading to protective or detrimental outcomes have not been fully elucidated. Helper innate lymphoid cells (hILCs), an innate lymphocyte recently discovered, functionally resemble T-helper cells and are important in inflammation and homeostasis. However, the role of hILCs in DENV infection had been unexplored. Methods: We performed flow cytometry to investigate the frequency and phenotype of hILCs in peripheral blood mononuclear cells from DENV-infected patients of different disease severities (DF and DHF), and at different phases (febrile and convalescence) of infection. Intracellular cytokine staining of hILCs from DF and DHF were also evaluated by flow cytometry after ex vivo stimulation. Further, the hILCs were sorted and subjected to transcriptome analysis using RNA sequencing. Differential gene expression analysis was performed to compare the febrile and convalescent phase samples in DF and DHF. Selected differentially expressed genes were then validated by quantitative PCR. Results: Phenotypic analysis showed marked activation of all three hILC subsets during the febrile phase as shown by higher CD69 expression when compared to paired convalescent samples, although the frequency of hILCs remained unchanged. Upon ex vivo stimulation, hILCs from febrile phase DHF produced significantly higher IFN-γ and IL-4 when compared to those of DF. Transcriptomic analysis showed unique hILCs gene expression in DF and DHF, suggesting that divergent functions of hILCs may be associated with different disease severities. Differential gene expression analysis indicated that hILCs function both in cytokine secretion and cytotoxicity during the febrile phase of DENV infection. Conclusions: Helper ILCs are activated in the febrile phase of DENV infection and display unique transcriptomic changes as well as cytokine production that correlate with severity. Targeting hILCs during early innate response to DENV might help shape subsequent immune responses and potentially lessen the disease severity in the future.


Assuntos
Vírus da Dengue/imunologia , Dengue/imunologia , Imunidade Inata , Linfócitos T Auxiliares-Indutores/imunologia , Transcriptoma/imunologia , Dengue/patologia , Feminino , Humanos , Interferon gama/imunologia , Interleucina-4/imunologia , Masculino , Pessoa de Meia-Idade , RNA-Seq , Linfócitos T Auxiliares-Indutores/patologia
10.
PLoS Negl Trop Dis ; 15(5): e0009445, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-34014983

RESUMO

BACKGROUND: Dengue fever is the most common mosquito-borne infection worldwide where an expanding surveillance and characterization of this infection are needed to better inform the healthcare system. In this surveillance-based study, we explored the prevalence and distinguishing features of dengue fever amongst febrile patients in a large community-based health facility in southern peninsular Malaysia. METHODS: Over six months in 2018, we recruited 368 adults who met the WHO 2009 criteria for probable dengue infection. They underwent the following blood tests: full blood count, dengue virus (DENV) rapid diagnostic test (RDT), ELISA (dengue IgM and IgG), nested RT-PCR for dengue, multiplex qRT-PCR for Zika, Chikungunya and dengue as well as PCR tests for Leptopspira spp., Japanese encephalitis and West Nile virus. RESULTS: Laboratory-confirmed dengue infections (defined by positive tests in NS1, IgM, high-titre IgG or nested RT-PCR) were found in 167 (45.4%) patients. Of these 167 dengue patients, only 104 (62.3%) were positive on rapid diagnostic testing. Dengue infection was significantly associated with the following features: family or neighbours with dengue in the past week (AOR: 3.59, 95% CI:2.14-6.00, p<0.001), cutaneous rash (AOR: 3.58, 95% CI:1.77-7.23, p<0.001), increased temperature (AOR: 1.33, 95% CI:1.04-1.70, p = 0.021), leucopenia (white cell count < 4,000/µL) (AOR: 3.44, 95% CI:1.72-6.89, p<0.001) and thrombocytopenia (platelet count <150,000/µL)(AOR: 4.63, 95% CI:2.33-9.21, p<0.001). Dengue infection was negatively associated with runny nose (AOR: 0.47, 95% CI:0.29-0.78, p = 0.003) and arthralgia (AOR: 0.42, 95% CI:0.24-0.75, p = 0.004). Serotyping by nested RT-PCR revealed mostly mono-infections with DENV-2 (n = 64), DENV-1 (n = 32) and DENV-3 (n = 17); 14 co-infections occurred with DENV-1/DENV-2 (n = 13) and DENV-1/DENV-4 (n = 1). Besides dengue, none of the pathogens above were found in patients' serum. CONCLUSIONS: Acute undifferentiated febrile infections are a diagnostic challenge for community-based clinicians. Rapid diagnostic tests are increasingly used to diagnose dengue infection but negative tests should be interpreted with caution as they fail to detect a considerable proportion of dengue infection. Certain clinical features and haematological parameters are important in the clinical diagnosis of dengue infection.


Assuntos
Vírus da Dengue/imunologia , Dengue/diagnóstico , Dengue/epidemiologia , Adulto , Idoso , Anticorpos Antivirais/sangue , Antígenos Virais/sangue , Contagem de Células Sanguíneas , Estudos Transversais , Dengue/virologia , Ensaio de Imunoadsorção Enzimática , Feminino , Febre/diagnóstico , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Malásia/epidemiologia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase
11.
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
12.
Nat Commun ; 12(1): 3054, 2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-34031380

RESUMO

About 20-25% of dengue virus (DENV) infections become symptomatic ranging from self-limiting fever to shock. Immune gene expression changes during progression to severe dengue have been documented in hospitalized patients; however, baseline or kinetic information is difficult to standardize in natural infection. Here we profile the host immunotranscriptome response in humans before, during, and after infection with a partially attenuated rDEN2Δ30 challenge virus (ClinicalTrials.gov NCT02021968). Inflammatory genes including type I interferon and viral restriction pathways are induced during DENV2 viremia and return to baseline after viral clearance, while others including myeloid, migratory, humoral, and growth factor immune regulation factors pathways are found at non-baseline levels post-viremia. Furthermore, pre-infection baseline gene expression is useful to predict rDEN2Δ30-induced immune responses and the development of rash. Our results suggest a distinct immunological profile for mild rDEN2Δ30 infection and offer new potential biomarkers for characterizing primary DENV infection.


Assuntos
Anticorpos Antivirais/genética , Anticorpos Antivirais/imunologia , Vírus da Dengue/genética , Vírus da Dengue/imunologia , Dengue/imunologia , Sorogrupo , Anticorpos Neutralizantes , Dengue/virologia , Regulação da Expressão Gênica , Humanos , Imunogenética , Interferon Tipo I/genética , Dengue Grave , Transcriptoma , Viremia
13.
Nat Commun ; 12(1): 2619, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976183

RESUMO

After the Zika virus (ZIKV) epidemic in the Americas in 2016, both Zika and dengue incidence declined to record lows in many countries in 2017-2018, but in 2019 dengue resurged in Brazil, causing ~2.1 million cases. In this study we use epidemiological, climatological and genomic data to investigate dengue dynamics in recent years in Brazil. First, we estimate dengue virus force of infection (FOI) and model mosquito-borne transmission suitability since the early 2000s. Our estimates reveal that DENV transmission was low in 2017-2018, despite conditions being suitable for viral spread. Our study also shows a marked decline in dengue susceptibility between 2002 and 2019, which could explain the synchronous decline of dengue in the country, partially as a result of protective immunity from prior ZIKV and/or DENV infections. Furthermore, we performed phylogeographic analyses using 69 newly sequenced genomes of dengue virus serotype 1 and 2 from Brazil, and found that the outbreaks in 2018-2019 were caused by local DENV lineages that persisted for 5-10 years, circulating cryptically before and after the Zika epidemic. We hypothesize that DENV lineages may circulate at low transmission levels for many years, until local conditions are suitable for higher transmission, when they cause major outbreaks.


Assuntos
Vírus da Dengue/imunologia , Dengue/epidemiologia , Suscetibilidade a Doenças/imunologia , Epidemias/estatística & dados numéricos , Infecção por Zika virus/imunologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antivirais/imunologia , Brasil/epidemiologia , Criança , Pré-Escolar , Dengue/imunologia , Dengue/transmissão , Dengue/virologia , Vírus da Dengue/genética , Vírus da Dengue/isolamento & purificação , Epidemias/prevenção & controle , Monitoramento Epidemiológico , Feminino , Genoma Viral/genética , Humanos , Imunidade Heteróloga , Incidência , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Tipagem Molecular , Mosquitos Vetores/virologia , Filogeografia , Sorotipagem , Adulto Jovem , Zika virus/imunologia , Infecção por Zika virus/epidemiologia
14.
PLoS Negl Trop Dis ; 15(4): e0009312, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33793562

RESUMO

A shift in dengue cases toward the adult population, accompanied by an increased risk of severe cases of dengue in the elderly, has created an important emerging issue in the past decade. To understand the level of past DENV infection among older adults after a large dengue outbreak occurred in southern Taiwan in 2015, we screened 1498 and 2603 serum samples from healthy residents aged ≥ 40 years in Kaohsiung City and Tainan City, respectively, to assess the seroprevalence of anti-DENV IgG in 2016. Seropositive samples were verified to exclude cross-reaction from Japanese encephalitis virus (JEV), using DENV/JEV-NS1 indirect IgG ELISA. We further identified viral serotypes and secondary DENV infections among positive samples in the two cities. The overall age-standardized seroprevalence of DENV-IgG among participants was 25.77% in Kaohsiung and 11.40% in Tainan, and the seroprevalence was significantly higher in older age groups of both cities. Although the percentages of secondary DENV infection in Kaohsiung and Tainan were very similar (43.09% and 44.76%, respectively), DENV-1 and DENV-2 spanned a wider age range in Kaohsiung, whereas DENV-2 was dominant in Tainan. As very few studies have obtained the serostatus of DENV infection in older adults and the elderly, this study highlights the need for further investigation into antibody status, as well as the safety and efficacy of dengue vaccination in these older populations.


Assuntos
Anticorpos Antivirais/sangue , Vírus da Dengue/imunologia , Dengue/epidemiologia , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Vírus da Dengue/genética , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estudos Soroepidemiológicos , Taiwan/epidemiologia
15.
J Virol ; 95(12)2021 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-33789994

RESUMO

The mosquito-borne Zika virus (ZIKV) has spread rapidly into regions where dengue virus (DENV) is endemic, and flavivirus cross-reactive T cell responses have been observed repeatedly in animal models and in humans. Preexisting cellular immunity to DENV is thought to contribute to protection in subsequent ZIKV infection, but the epitope targets of cross-reactive T cell responses have not been comprehensively identified. Using human blood samples from the regions of Nicaragua and Sri Lanka where DENV is endemic that were collected before the global spread of ZIKV in 2016, we employed an in vitro expansion strategy to map ZIKV T cell epitopes in ZIKV-unexposed, DENV-seropositive donors. We identified 93 epitopes across the ZIKV proteome, and we observed patterns of immunodominance that were dependent on antigen size and sequence identity to DENV. We confirmed the immunogenicity of these epitopes through a computational HLA binding analysis, and we showed that cross-reactive T cells specifically recognize ZIKV peptides homologous to DENV sequences. We also found that these CD4 responses were derived from the memory T cell compartment. These data have implications for understanding the dynamics of flavivirus-specific T cell immunity in areas of endemicity.IMPORTANCE Multiple flaviviruses, including Zika virus (ZIKV) and the four serotypes of dengue virus (DENV), are prevalent in the same large tropical and equatorial areas, which are inhabited by hundreds of millions of people. The interplay of DENV and ZIKV infection is especially relevant, as these two viruses are endemic in largely overlapping regions, have significant sequence similarity, and share the same arthropod vector. Here, we define the targets of preexisting immunity to ZIKV in unexposed subjects in areas where dengue is endemic. We demonstrate that preexisting immunity to DENV could shape ZIKV-specific responses, and DENV-ZIKV cross-reactive T cell populations can be expanded by stimulation with ZIKV peptides. The issue of potential ZIKV and DENV cross-reactivity is of relevance for understanding patterns of natural immunity, as well as for the development of diagnostic tests and vaccines.


Assuntos
Linfócitos T CD4-Positivos/imunologia , Memória Imunológica , Linfócitos T/imunologia , Infecção por Zika virus/imunologia , Zika virus/imunologia , Adulto , Antígenos Virais/química , Antígenos Virais/imunologia , Reações Cruzadas , Dengue/imunologia , Dengue/virologia , Vírus da Dengue/imunologia , Epitopos de Linfócito T/imunologia , Antígenos HLA/metabolismo , Humanos , Peptídeos/imunologia , Proteínas Virais/química , Proteínas Virais/imunologia
16.
Int J Infect Dis ; 108: 443-453, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33894353

RESUMO

OBJECTIVES: To estimate the incidence of dengue infection across geographically distinct areas of Brazil. METHODS: This prospective, household-based, cohort study enrolled participants in five areas and followed them up for up to 4 years (2014-2018). Dengue seroprevalence was assessed at each scheduled visit. Suspected dengue cases were identified through enhanced passive and active surveillance. Acute symptomatic dengue infection was confirmed through reverse-transcriptase quantitative polymerase chain reaction in combination with an antigenic assay (non-structural protein 1) and serology. RESULTS: Among 3300 participants enrolled, baseline seroprevalence was 76.2%, although only 23.3% of participants reported a history of dengue. Of 1284 suspected symptomatic dengue cases detected, 50 (3.9%) were laboratory-confirmed. Based on 8166.5 person-years (PY) of follow-up, the incidence of laboratory-confirmed symptomatic infection (primary endpoint) was 6.1 per 1000 PY (95% confidence interval [CI]: 4.5, 8.1). Incidence varied substantially in different years (1.8-7.4 per 1000 PY). The incidence of inapparent primary dengue infection was substantially higher: 41.7 per 1000 PY (95% CI: 31.1, 54.6). CONCLUSIONS: Our findings, highlighting that the incidence of dengue infection is underestimated in Brazil, will inform the design and implementation of future dengue vaccine trials. CLINICAL TRIAL REGISTRATION: NCT01751139.


Assuntos
Dengue/epidemiologia , Adolescente , Adulto , Infecções Assintomáticas/epidemiologia , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos de Coortes , Vírus da Dengue/imunologia , Características da Família , Feminino , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Soroepidemiológicos , Adulto Jovem
17.
Viruses ; 13(4)2021 03 31.
Artigo em Inglês | MEDLINE | ID: mdl-33807442

RESUMO

Flaviviruses circulate worldwide and cause a number of medically relevant human diseases, such as dengue, Zika, yellow fever, and tick-borne encephalitis (TBE). Serology plays an important role in the diagnosis of flavivirus infections, but can be impeded by antigenic cross-reactivities among flaviviruses. Therefore, serological diagnosis of a recent infection can be insufficiently specific, especially in areas where flaviviruses co-circulate and/or vaccination coverage against certain flaviviruses is high. In this study, we developed a new IgM assay format, which is well suited for the specific diagnosis of TBE, Zika and dengue virus infections. In the case of TBE and Zika, the IgM response proved to be highly specific for the infecting virus. In contrast, primary dengue virus infections induced substantial amounts of cross-reactive IgM antibodies, which is most likely explained by structural peculiarities of dengue virus particles. Despite the presence of cross-reactive IgM, the standardized nature and the quantitative read-out of the assay even allowed the serotype-specific diagnosis of recent dengue virus infections in most instances.


Assuntos
Anticorpos Antivirais/sangue , Antígenos Virais/imunologia , Reações Cruzadas/imunologia , Infecções por Flavivirus/diagnóstico , Flavivirus/imunologia , Imunoglobulina M/sangue , Testes Sorológicos/métodos , Antígenos Virais/classificação , Estudos de Coortes , Dengue/sangue , Dengue/diagnóstico , Dengue/imunologia , Vírus da Dengue/imunologia , Vírus da Encefalite Transmitidos por Carrapatos/imunologia , Encefalite Transmitida por Carrapatos/diagnóstico , Encefalite Transmitida por Carrapatos/imunologia , Flavivirus/classificação , Infecções por Flavivirus/sangue , Infecções por Flavivirus/virologia , Humanos , Sorogrupo , Testes Sorológicos/normas , Zika virus/imunologia , Infecção por Zika virus/sangue , Infecção por Zika virus/diagnóstico , Infecção por Zika virus/imunologia
18.
Trends Biochem Sci ; 46(7): 519-521, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33895084

RESUMO

The flavivirus genus consists of several major human pathogens including dengue (DENV) and Zika viruses. The flavivirus nonstructural protein 1 (NS1) plays an important role in disease progression, for example, in the development of severe dengue disease. Anti-NS1 antibodies have been shown to confer protection, and two new studies by Biering et al. and Modhiran et al. on the structure of NS1:antibody complexes reveal their mechanism of neutralization.


Assuntos
Vírus da Dengue , Dengue , Flavivirus , Infecção por Zika virus , Zika virus , Anticorpos Antivirais , Vírus da Dengue/imunologia , Humanos , Proteínas não Estruturais Virais
19.
Front Immunol ; 12: 618577, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815373

RESUMO

Abnormal immune responses and cytokine storm are involved in the development of severe dengue, a life-threatening disease with high mortality. Dengue virus-induced neutrophil NETosis response is associated with cytokine storm; while the role of viral factors on the elicitation of excessive inflammation mains unclear. Here we found that treatments of dengue virus envelope protein domain III (EIII), cellular binding moiety of virion, is sufficient to induce neutrophil NETosis processes in vitro and in vivo. Challenges of EIII in inflammasome Nlrp3 -/- and Casp1 -/- mutant mice resulted in less inflammation and NETosis responses, as compared to the wild type controls. Blockages of EIII-neutrophil interaction using cell-binding competitive inhibitor or selective Nlrp3 inflammasome inhibitors OLT1177 and Z-WHED-FMK can suppress EIII-induced NETosis response. These results collectively suggest that Nlrp3 inflammsome is a molecular target for treating dengue-elicited inflammatory pathogenesis.


Assuntos
Armadilhas Extracelulares/imunologia , Inflamassomos/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Domínios e Motivos de Interação entre Proteínas/imunologia , Proteínas do Envelope Viral/imunologia , Animais , Linhagem Celular , Dengue/imunologia , Dengue/metabolismo , Dengue/virologia , Vírus da Dengue/imunologia , Imunofenotipagem , Camundongos , Camundongos Knockout , Mitocôndrias/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Proteínas Recombinantes , Proteínas do Envelope Viral/química
20.
PLoS One ; 16(4): e0249602, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33793682

RESUMO

INTRODUCTION: Early and rapid confirmation of dengue infections strengthens disease surveillance program and are critical to the success of vector control measures. Rapid diagnostics tests (RDTs) are increasingly used to confirm recent dengue infections due to their ease of use and short turnaround time for results. Several studies undertaken in dengue-endemic Southeast Asia have reported the performance of RDTs against enzyme-linked immunosorbent assay (ELISA), reverse transcriptase polymerase chain reaction (RT-PCR) and virus isolation methods. However, few studies have compared multiple RDTs for the detection of dengue NS1 antigen and IgM antibody in a single combo cassette. We evaluated six RDTs in Singapore for their utility in routine clinical testing to detect recent dengue infections. METHODS: The evaluation comprised two phases. The first phase sought to determine each RDT's specificity to dengue NS1 and IgM using zika and chikungunya virus supernatant and zika convalescent samples. RDTs that cross-reacted with zika or chikungunya were not further tested in phase 2. The second phase sought to determine the sensitivity and specificity of the remaining RDTs to dengue NS1 and IgM using pre-characterised dengue specimens and non-dengue/chikungunya febrile clinical specimens. RESULTS: None of the RDTs cross-reacted with zika IgM in Phase 1. Truquick and Quickprofile cross reacted with zika and chikungunya viruses and were not evaluated thereafter. Standard Q had the highest dengue NS1 and IgM sensitivity at 87.0% and 84.3% respectively whereas Bioline (68.5%) and Multisure (58.3%) had the lowest dengue NS1 and IgM sensitivity respectively. Combining dengue NS1/IgM detection results greatly improved the RDT ability to detect recent dengue infection; Standard Q had the highest sensitivity at 99.1% while Multisure had the lowest at 92.6%. All the RDTs were highly specific for dengue NS1 and IgM (96.7% to 100%). All the RDTs had high positive predictive values (98.4% to 100%) for NS1, IgM and combined NS1/IgM parameters whereas Standard Q had the highest negative predictive values at 68.2% (NS1), 63.8% (IgM) and 96.8% (NS1/IgM). For the RDTs, detection of NS1 declined from acute to convalescent phase of illness whereas IgM detection rate gradually increased over time. CONCLUSION: In our study, several RDTs were evaluated for their diagnostic accuracy and capability in detecting recent dengue infection. Standard Q demonstrated a high degree of diagnostic accuracy and capability in the detection of NS1 and IgM biomarkers. RDTs can provide rapid and accurate confirmation of recent dengue infections and augment dengue surveillance and control programmes. Further studies are required to assess the usefulness of these RDTs in other epidemiology settings.


Assuntos
Anticorpos Antivirais/imunologia , Vírus da Dengue/imunologia , Dengue/diagnóstico , Testes Diagnósticos de Rotina/métodos , Imunoglobulina M/imunologia , Kit de Reagentes para Diagnóstico/estatística & dados numéricos , Adulto , Anticorpos Antivirais/sangue , Dengue/sangue , Dengue/imunologia , Dengue/virologia , Ensaio de Imunoadsorção Enzimática , Humanos , Imunoglobulina M/sangue , Singapura/epidemiologia
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