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1.
Org Biomol Chem ; 22(11): 2218-2225, 2024 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-38358380

RESUMO

Chronic infection with hepatitis B virus (HBV) is a major cause of cirrhosis and liver cancer. Capsid assembly modulators can induce error-prone assembly of HBV core proteins to prevent the formation of infectious virions, representing promising candidates for treating chronic HBV infections. To explore novel capsid assembly modulators from unexplored mirror-image libraries of natural products, we have investigated the synthetic process of the HBV core protein for preparing the mirror-image target protein. In this report, the chemical synthesis of full-length HBV core protein (Cp183) containing an arginine-rich nucleic acid-binding domain at the C-terminus is presented. Sequential ligations using four peptide segments enabled the synthesis of Cp183 via convergent and C-to-N direction approaches. After refolding under appropriate conditions, followed by the addition of nucleic acid, the synthetic Cp183 assembled into capsid-like particles.


Assuntos
Hepatite B , Ácidos Nucleicos , Humanos , Capsídeo/química , Proteínas do Capsídeo/metabolismo , Vírus da Hepatite B , Hepatite B/metabolismo , Proteínas do Core Viral/análise , Proteínas do Core Viral/química , Proteínas do Core Viral/metabolismo , Replicação Viral , Antivirais/metabolismo
2.
J Mol Biol ; 434(7): 167501, 2022 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-35183559

RESUMO

Hepatitis C virus (HCV) core is a highly conserved and multifunctional protein that forms the viral capsid, making it an attractive target for HCV detection and inhibition. Aptamers are in vitro selected, single-stranded nucleic acids (RNA or ssDNA) with growing applicability in viral diagnostics and therapy. We have carried out DNA and RNA in vitro selection against six different variants of HCV core protein: two versions of the full-length protein of genotype 1, and the hydrophilic domain of genotypes 1 to 4. The aptamer populations obtained were analyzed by means of Ultra-Deep Sequencing (UDS), the most abundant sequences were identified and a number of highly represented sequence motifs were unveiled. Affinity (measured as the dissociation constant, Kd) of the most abundant DNA and RNA aptamers were quantified using Enzyme-Linked OligoNucleotide Assay (ELONA)-based methods. Some aptamers with nanomolar or subnanomolar Kd values (as low as 0.4 nM) were the common outcome of DNA and RNA selections against different HCV core variants. They were tested in sandwich and competitive biosensor assays, reaching a limit of detection for HCV core of 2 pM. Additionally, the two most prevalent and high affinity aptamers were assayed in Huh-7.5 reporter cell lines infected with HCV, where they decreased both the viral progeny titer and the extracellular viral RNA level, while increasing the amount of intracellular viral RNA. Our results suggest that these aptamers inhibit HCV capsid assembly and virion formation, thus making them good candidate molecules for the design of novel therapeutic approaches for hepatitis C.


Assuntos
Aptâmeros de Nucleotídeos , Hepacivirus , Hepatite C , Técnica de Seleção de Aptâmeros , Proteínas do Core Viral , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/genética , Capsídeo , Técnicas de Cultura de Células , DNA/química , DNA/genética , Genótipo , Hepacivirus/genética , Hepacivirus/isolamento & purificação , Hepacivirus/fisiologia , Hepatite C/diagnóstico , Humanos , RNA/química , RNA/genética , Técnica de Seleção de Aptâmeros/métodos , Proteínas do Core Viral/análise , Proteínas do Core Viral/genética , Montagem de Vírus
3.
Clin Exp Med ; 20(1): 131-141, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31664538

RESUMO

Value of hepatitis C virus (HCV) core antigen (cAg) test has been controversy in patients with low HCV loads for its lower sensitivity. We assessed correlation between HCV-cAg and HCV RNA in serum samples with low viral loads and analyzed the performance of HCV-cAg assay in determining diagnosis and treatment outcomes in chronic hepatitis C patients. Both HCV RNA and HCV-cAg were detected for 2298 serum samples. Correlation analysis was performed between the two tests. Receiver operating characteristics (ROC) curve was used to assess value of HCV-cAg test in determining diagnosis and response outcomes at the different HCV RNA thresholds. The two tests were correlated very well, and moreover, correlation in the low viral load group was higher than that in the high viral load group (r value: 0.901 and 0.517). Positive agreement of HCV-cAg ≥ 3 fmol/L was as high as 97.0% for HCV RNA ≥ 1000 IU/mL, and its negative agreement for HCV RNA < 15 IU/mL was up to 98.9% in all samples. Area under ROCs ranged from 0.939 to 0.992, regardless of HCV RNA thresholds. When lower limit of detection of HCV RNA was 15, 100 or 1000 IU/mL, positive predictive value of HCV-cAg was 96.8%, 98.8% or 92.4%, and its negative predictive value was 87.0%, 89.9% or 98.3%, respectively, on the basis of different cutoff values. High-sensitivity HCV-cAg detection may likely replace HCV RNA to confirm the existence of HCV and to guide the treatment of chronic HCV infection.


Assuntos
Hepacivirus/genética , Hepatite C Crônica/diagnóstico , RNA Viral/genética , Proteínas do Core Viral/análise , Adulto , Ensaios Clínicos como Assunto , Feminino , Hepacivirus/imunologia , Antígenos da Hepatite C/análise , Hepatite C Crônica/imunologia , Hepatite C Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade , Carga Viral
4.
Anal Chem ; 91(15): 10001-10007, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31269392

RESUMO

Paper-based lateral flow immunoassays (LFIAs) using conventional sandwich-type immunoassays are one of the most commonly used point-of-care (PoC) tests. However, the application of gold nanoparticles (AuNPs) in LFIAs does not meet sensitivity requirements for the detection of infectious diseases or biomarkers present at low concentrations in body fluids because of the limited number of AuNPs that can bind to the target. To overcome this problem, we first developed a single-stranded DNA binding protein (RPA70A, DNA binding domain A of human Replication Protein A 70 kDa) conjugated to AuNPs for a sandwich assay using a capture antibody immobilized in the LFIA and an aptamer as a detection probe, thus, enabling signal intensity enhancement by attaching several AuNPs per aptamer. We applied this method to detect the influenza nucleoprotein (NP) and cardiac troponin I (cTnI). We visually detected spiked targets at a low femtomolar range, with limits of detection for NP in human nasal fluid and for cTnI in serum of 0.26 and 0.23 pg·mL-1, respectively. This technique showed significantly higher sensitivity than conventional methods that are widely used in LFIAs involving antibody-conjugated AuNPs. These results suggest that the proposed method can be universally applied to the detection of substances requiring high sensitivity and can be used in the field of PoC testing for early disease diagnosis.


Assuntos
Biomarcadores/sangue , Ouro/química , Imunoensaio/métodos , Nanopartículas Metálicas/química , Proteína de Replicação A/química , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/metabolismo , Biomarcadores/análise , Humanos , Limite de Detecção , Líquido da Lavagem Nasal/química , Proteínas do Nucleocapsídeo , Papel , Sistemas Automatizados de Assistência Junto ao Leito , Troponina I/sangue , Proteínas do Core Viral/análise , Proteínas do Core Viral/imunologia
5.
Jpn J Infect Dis ; 72(5): 285-291, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-30918148

RESUMO

An advanced and fully automated chemiluminescent enzyme immunoassay for the hepatitis C virus core antigen (HCVcAg) was recently developed in Japan. We aimed to evaluate its clinical utility. The new Fujirebio assay (Lumipulse Presto HCVcAg [LP-Presto]) was compared with 2 conventional assays (Lumipulse Ortho HCVcAg [LP-Ortho] and Abbott's Architect HCVcAg). Basic assessments of LP-Presto (reproducibility, stability, range of quantitation, and specificity) were performed on 220 frozen sera (83 positive and 137 negative by LP-Ortho) and 206 fresh sera (all negative by LP-Ortho). Correlation analysis was performed and the rates of concordance for each assay were determined. Additionally, the frozen sera of 42 hyperimmunoglobulinemia patients, including 3 unmeasurable by LP-Ortho, were tested by LP-Presto. All the basic assessments of LP-Presto were consistent with the results of LP-Ortho and Architect. The concordance rate between LP-Presto and LP-Ortho for the 220 frozen sera was 99.5% (219/220), and that between LP-Presto and Architect was 99.1% (218/220). LP-Presto (HCVcAg cut-off value; 20 fmol/L) was fully consistent with LP-Ortho (100%), which found 343 sera negative for HCVcAg. All 42 hyperimmunoglobulinemic sera were measurable using LP-Presto. In conclusion, the performance of LP-Presto was rapid and reliable, and nonspecific test results due to hyperimmunoglobulinemia were reduced when LP-Presto was used. Therefore, LP-Presto is a high-quality HCVcAg assay that shows promising applications.


Assuntos
Hepatite C/diagnóstico , Técnicas Imunoenzimáticas/métodos , Medições Luminescentes/métodos , Proteínas do Core Viral/análise , Adulto , Idoso de 80 Anos ou mais , Automação Laboratorial/métodos , Feminino , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
6.
Virus Res ; 260: 102-113, 2019 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-30508604

RESUMO

Orthohantaviruses Hantaan (HTNV) and Puumala (PUUV) virus cause hemorrhagic fever with renal syndrome (HFRS), that is characterized by acute renal failure with often massive proteinuria and by morphological changes of the tubular and glomerular apparatus. Orthohantaviral N protein is found in renal cells and plays a key role in replication. However, the replication in human renal cells is not well characterized. Therefore, we examined the orthohantaviral infection in different human renal cells. Differences in localization of N protein, release of particles, and modulation of the actin cytoskeleton between both virus species are observed in human renal cells. A substantial portion of HTNV N protein demonstrates a filamentous pattern in addition to the typical punctate pattern. Release of HTNV depends on an intact actin and microtubule cytoskeleton. In contrast, PUUV N protein is generally localized in a punctate pattern and release of PUUV does not require an intact actin cytoskeleton. Infection of podocytes results in cytoskeletal rearrangements that are more pronounced for HTNV. Analyzing Vero E6 cells revealed differences compared to human renal cells. The pattern of N proteins is strictly punctate, release does not depend on an intact actin cytoskeleton and cytoskeletal rearrangements are not present. No virus-specific variations between HTNV and PUUV are observed in Vero E6 cells. Using human renal cells as cell culture model for orthohantavirus infection demonstrates virus-specific differences and orthohantavirus-induced cytoskeletal rearrangements that are not observed in Vero E6 cells. Therefore, the choice of an appropriate cell culture system is a prerequisite to study orthohantavirus pathogenicity.


Assuntos
Células Epiteliais/virologia , Vírus Hantaan/crescimento & desenvolvimento , Virus Puumala/crescimento & desenvolvimento , Replicação Viral , Animais , Variação Biológica da População , Proteínas do Capsídeo/análise , Linhagem Celular , Chlorocebus aethiops , Citoesqueleto/metabolismo , Humanos , Proteínas do Nucleocapsídeo/análise , Proteínas do Core Viral/análise , Liberação de Vírus
7.
J Med Virol ; 91(1): 45-55, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30153335

RESUMO

Influenza is a highly infectious disease caused by three types of viruses, including influenza A virus (IAV), influenza B virus, and, rarely, influenza C virus. IAV is a major, global public health threat, causing approximately 500 000 deaths per year worldwide. The new strains of IAV have emerged due to a mutation called antigenic shift, which results in a new subtype of the virus that shows resistance to common antiviral drugs. Here, guava and lemon extracts, including green leaves and flowers, were investigated for their activity against IAV replication in human A549 cells. Concomitantly, the cytotoxicity of a potent extract on host-cell multiplication was assessed. Our results reveal that guava extracts inhibit IAV replication, indicated by viral nucleoprotein expression profile and traditional plaque assay. Interestingly, treatment with guava extract inactivates Akt protein kinase and stimulates the pro-apoptotic protein P53, at early stages of infection. Furthermore, purified guava flavonoid glycosides (GFGs) show competitive inhibition of IAV-virus replication via early regulation of IL-1ß and IL-8 in association with P53 gene expression. The docking analysis of GFGs and the protein structure of upstream targets for the Akt signaling pathway indicates a sufficient interaction and stabilization with Gbr2 protein. These data indicate that treatment with GFGs disturbs IAV replication via activation of P53 and its apoptotic related factors after infection. Collectively, these data show that targeting of essential host kinases that are involved in the replication cycle of IAV and rescue of P53 activity by GFGs could represent a new strategy to eradicate IAV.


Assuntos
Antivirais/farmacologia , Glicosídeos/metabolismo , Vírus da Influenza A/crescimento & desenvolvimento , Extratos Vegetais/farmacologia , Psidium/química , Proteína Supressora de Tumor p53/metabolismo , Replicação Viral/efeitos dos fármacos , Células A549 , Antivirais/isolamento & purificação , Citrus/química , Glicosídeos/isolamento & purificação , Humanos , Vírus da Influenza A/efeitos dos fármacos , Interleucina-1beta/metabolismo , Interleucina-8/metabolismo , Proteínas do Nucleocapsídeo , Extratos Vegetais/isolamento & purificação , Proteínas de Ligação a RNA/análise , Proteínas do Core Viral/análise , Ensaio de Placa Viral
8.
BMC Infect Dis ; 18(1): 622, 2018 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-30514229

RESUMO

BACKGROUND: Nucleic acid tests performed on blood samples collected on Dried Blood Spot (DBS) and detection of HCV core antigen (HCVcAg) are two approaches that may facilitate access to HCV diagnosis in low and middle incomes countries. In this study we evaluate HCV RNA and HCV antigen testing on DBS in HIV/HCV co-infected peoples who inject drugs in Vietnam. METHOD: One hundred and four HIV/HCV seropositive patients managed in outpatient care at the Haiphong Viet Tiep hospital were included in this study from February to March, 2014 (ANRS 12262 study). RESULTS: Eighty-six subjects were tested positive for HCV RNA in serum, median (IQR): 6.9 log10 IU/ml (5.6-7.4 log10 IU/ml). Genotypes consisted of 57 G1 (69%), 3 G3 (4%), and 22 G6 (27%). HCV RNA was detected on DBS specimens in 79 out 86 subjects with chronic hepatitis C (sensitivity 92.5%; 95% CI: 85.1-96.9%). HCV RNA level on DBS and serum was moderately correlated (r = 0.24; p = 0.05) suggesting a degradation of HCV RNA due to transportation and storage conditions. HCVcAg was detected in 75/86 dB specimens (sensitivity: 87.2%; 95% CI: 78.3-93.4%), with a strong positive relationship between DBS HCVcAg and serum HCV RNA levels (r = 0.80; P < 0.0001). CONCLUSIONS: Quantification of HCVcAg on DBS appears to benefit from substantial stability under prolonged storage conditions but with a lower analytical sensitivity compared to DBS HCV RNA testing. Detection of HCV RNA on DBS is an interesting approach for confirming viral replication in HCV seropositive persons but the impact of pre-analytical conditions on the integrity of HCV RNA needs to be controlled.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Infecções por HIV/virologia , Hepatite C/virologia , RNA Viral/análise , Abuso de Substâncias por Via Intravenosa/virologia , Proteínas do Core Viral/análise , Viremia/diagnóstico , Adulto , Coinfecção , Estudos Transversais , Testes Diagnósticos de Rotina , Usuários de Drogas , Feminino , Genótipo , HIV/genética , Infecções por HIV/sangue , Infecções por HIV/complicações , Hepacivirus/genética , Hepatite C/sangue , Hepatite C/complicações , Hepatite C/diagnóstico , Humanos , Testes Imunológicos , Injeções , Masculino , RNA Viral/sangue , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Abuso de Substâncias por Via Intravenosa/sangue , Abuso de Substâncias por Via Intravenosa/complicações , Vietnã , Proteínas do Core Viral/sangue , Proteínas do Core Viral/genética , Viremia/sangue , Viremia/genética
9.
Antiviral Res ; 160: 55-63, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30339849

RESUMO

Supplementation with vitamin D (VD) has been reported to improve the efficacy of interferon-based therapy for chronic hepatitis C. We found that 25-hydroxyvitamin D3 (25-(OH)D3), one of the metabolites of VD, has antiviral effects by inhibiting the infectious virus production of the hepatitis C virus (HCV). In this study, to clarify the underlying mechanisms of the anti-HCV effects, we searched VD derivatives that have anti-HCV effects and identified the common target molecule in the HCV life cycle by using an HCV cell culture system. After infection of Huh-7.5.1 cells with cell culture-generated HCV, VD derivatives were added to culture media, and the propagation of HCV was assessed by measuring the HCV core antigen levels in culture media and cell lysates. To determine the step in the HCV life cycle affected by these compounds, the single-cycle virus production assay was used with a CD81-negative cell line. Of the 14 structural derivatives of VD, an anti-HCV effect was detected in 9 compounds. Cell viability was not affected by these effective compounds. The 2 representative VD derivatives inhibited the infectious virus production in the single-cycle virus production assay. Treatment with these compounds and 25-(OH)D3 suppressed the expression of apolipoprotein A1 and C3, which are known to be involved in infectious virus production of HCV, and the knockdown of these apolipoproteins reduced infectious virus production. In conclusion, we identified several compounds with anti-HCV activity by screening VD derivatives. These compounds reduce the infectious virus production of HCV by suppressing the expression of apolipoproteins in host cells.


Assuntos
Antivirais/farmacologia , Apolipoproteína A-I/antagonistas & inibidores , Apolipoproteína C-III/antagonistas & inibidores , Hepacivirus/crescimento & desenvolvimento , Hepatócitos/virologia , Replicação Viral/efeitos dos fármacos , Vitamina D/farmacologia , Linhagem Celular , Meios de Cultura/química , Hepatócitos/enzimologia , Humanos , Proteínas do Core Viral/análise , Cultura de Vírus
10.
Arch Virol ; 163(10): 2871-2875, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29982961

RESUMO

A codon-optimized equine infectious anemia virus p26 gene was fused to a maltose-binding protein (MBP) and expressed in Escherichia coli for use as an antigen in agar gel immunodiffusion (AGID) and enzyme-linked immunosorbent assay (ELISA) for diagnosis of equine infectious anemia. An analysis of analytical sensitivity and specificity showed that the antigen MBP-p26rec reacted positively with a reference World Organization for Animal Health serum and demonstrated no cross-reaction against sera from vaccinated animals in either test. The diagnostic characteristics were evaluated and presented excellent values. The AGIDrec showed 100% sensitivity and specificity, and the ELISArec showed 100% sensitivity and 99.64% specificity. In addition, MBP-p26rec was stabile after three years of storage at 4 °C, maintaining its immunoreactivity.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Anemia Infecciosa Equina/virologia , Imunodifusão/métodos , Vírus da Anemia Infecciosa Equina/isolamento & purificação , Proteínas Ligantes de Maltose/análise , Proteínas do Core Viral/análise , Animais , Ensaio de Imunoadsorção Enzimática/instrumentação , Anemia Infecciosa Equina/diagnóstico , Anemia Infecciosa Equina/imunologia , Cavalos , Imunodifusão/instrumentação , Vírus da Anemia Infecciosa Equina/genética , Vírus da Anemia Infecciosa Equina/imunologia , Proteínas Ligantes de Maltose/genética , Proteínas Ligantes de Maltose/imunologia , Proteínas do Core Viral/genética , Proteínas do Core Viral/imunologia
11.
BMC Complement Altern Med ; 18(1): 184, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29903008

RESUMO

BACKGROUND: Influenza infection is a major public health threat. The role of influenza A virus-induced inflammatory response in severe cases of this disease is widely recognized. Drug resistance and side effects of chemical treatments have been observed, resulting in increased interest in alternative use of herbal medications for prophylaxis against this infection. The South African medicinal plant, Rapanea melanophloeos (RM) (L.) Mez of the family Myrsinaceae was selected owing to its traditional use for the treatment of several diseases such as respiratory ailments and also previous preliminary studies of anti-influenza activity of its methanolic extract. The aim of this study was to investigate the immunomodulatory properties of a glycoside flavone isolated from RM against influenza A virus. METHODS: The non-cytotoxic concentration of the quercetin-3-O-α-L-rhamnopyranoside (Q3R) was determined by MTT assay and tested for activity against influenza A virus (IAV) in simultaneous, pre-penetration and post-penetration combination treatments over 1 h incubation on MDCK cells. The virus titer and viral load targeting NP and M2 viral genes were determined using HA and qPCR, respectively. TNF-α and IL-27 as pro- and anti-inflammatory cytokines were measured at RNA and protein levels by qPCR and ELISA, respectively. RESULTS: Quercetin-3-O-α-L-rhamnopyranoside at 150 µg/ml decreased the viral titer by 6 logs (p < 0.01) in the simultaneous procedure. The NP and M2 genes copy numbers as viral target genes, calculated based on the Ct values and standard formula, significantly decreased in simultaneous treatment (p < 0.01). The expression of cytokines was also considerably affected by the compound treatment. CONCLUSIONS: This is the first report of quercetin-3-O-α-L-rhamnopyranoside from RM and its immunomodulatory properties against influenza A virus. Further research will focus on detecting the specific mechanism of virus-host interactions.


Assuntos
Antivirais/farmacologia , Glicosídeos/farmacologia , Fatores Imunológicos/farmacologia , Vírus da Influenza A/efeitos dos fármacos , Extratos Vegetais/química , Primulaceae/química , Quercetina/análogos & derivados , Animais , Citocinas/análise , Citocinas/genética , Citocinas/metabolismo , Variações do Número de Cópias de DNA/efeitos dos fármacos , Cães , Vírus da Influenza A/genética , Células Madin Darby de Rim Canino , Proteínas do Nucleocapsídeo , Quercetina/farmacologia , Proteínas de Ligação a RNA/análise , Proteínas de Ligação a RNA/genética , Proteínas do Core Viral/análise , Proteínas do Core Viral/genética , Proteínas da Matriz Viral/análise , Proteínas da Matriz Viral/genética
12.
J Med Virol ; 90(6): 1112-1120, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29446489

RESUMO

Alcohol could compromise the anti-hepatitis C virus (HCV) function of interferon-alpha (IFN-α). However, little information is available about the effect of alcohol on interferon-lambda (IFN-λ, type III IFN), a novel candidate for development of therapy for HCV infection. Huh7 cells were infected with HCV JFH-1 virus, then treated with alcohol, and/or IFN-λ1. RT-PCR and Western blot were used to detect the levels of HCV and key cellular factors. Overexpression or silencing expression was performed to verify the role of key factors in alcohol-attenuated anti-HCV function of IFN-λ1. Alcohol treatment compromised anti-HCV effect of IFN-λ1 in HCV JFH-1-infected Huh7 cells, evidenced by the significantly increased levels of HCV RNA, and HCV core protein in alcohol-/IFN-λ1-treated cells compared to cells with IFN-λ1 treatment alone. Investigation of the mechanisms responsible for the alcohol action revealed that alcohol enhanced the expression of protein inhibitor of activated STAT (PIASy). Overexpression of PIASy compromised anti-HCV ability of IFN-λ1, whereas silencing expression of PIASy partly restored the alcohol-attenuated anti-HCV effect of IFN-λ1. More importantly, overexpression of PIASy significantly down-regulated the level of IFN-λ1-indcued phosphorylation of STAT1 (p-STAT1), an important adaptor in IFN-λ pathway, as well as reduced the expression of IFN-λ1-induced IFN-stimulated genes 56 (ISG56), and myxovirus resistance 1 (Mx1), two antiviral effectors in in IFN-λ pathway. These findings indicate that alcohol, through inducing the expression of negative regulator in IFN-λ pathway, inhibits IFN-λ-mediated anti-HCV action in human hepatic cells, which may lead to the poor efficacy of IFN-λ-based therapy against HCV infection.


Assuntos
Álcoois/metabolismo , Hepacivirus/imunologia , Hepatócitos/imunologia , Interleucinas/antagonistas & inibidores , Proteínas de Ligação a Poli-ADP-Ribose/biossíntese , Proteínas Inibidoras de STAT Ativados/biossíntese , Regulação para Cima , Western Blotting , Linhagem Celular , Perfilação da Expressão Gênica , Hepacivirus/crescimento & desenvolvimento , Hepatócitos/efeitos dos fármacos , Hepatócitos/virologia , Humanos , Interferons , RNA Viral/análise , Reação em Cadeia da Polimerase em Tempo Real , Proteínas do Core Viral/análise
13.
J Virol Methods ; 251: 99-105, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29042217

RESUMO

In the present study, the possibility of hepatitis C virus core antigen (HCVcoreAg) detection in buffer solution, using atomic force microscope chip (AFM-chip) with immobilized aptamers, has been demonstrated. The target protein was detected in 1mL of solution at concentrations from 10-10М to 10-13М. The registration of aptamer/antigen complexes on the chip surface was carried out by atomic force microscopy (AFM). The further mass-spectrometric (MS) identification of AFM-registered objects on the chip surface allowed reliable identification of HCVcoreAg target protein in the complexes. Aptamers, which were designed for therapeutic purposes, have been shown to be effective in HCVcoreAg detection as probe molecules.


Assuntos
Aptâmeros de Nucleotídeos/metabolismo , Microscopia de Força Atômica/métodos , Proteínas do Core Viral/análise
14.
J Int AIDS Soc ; 20(1): 21856, 2017 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-28953324

RESUMO

INTRODUCTION: A lack of access to hepatitis C virus (HCV) diagnostics is a significant barrier to achieving the World Health Organization 2030 global elimination goal. HCV core antigen (HCVcAg) quantification and dried blood spot (DBS) are appealing alternatives to conventional HCV serology and nucleic acid testing (NAT) for resource-constraint settings, particularly in difficult-to-reach populations. We assessed the accuracy of serum and DBS HCVcAg testing in people who inject drugs in Tanzania using HCV NAT as a reference. METHOD: Between May and July 2015, consecutive HCV-seropositive patients enrolled in the local opioid substitution treatment centre were invited to participate in the study. All had HCV RNA detection (Roche Molecular Systems, Pleasanton, CA, USA), genotyping (NS5B gene phylogenetic analysis) and HCVcAg on blood samples and DBS (Architect assay; Abbott Diagnostics, Chicago, IL, USA). RESULTS: Out of 153 HCV-seropositive individuals, 65 (42.5%) and 15 (9.8%) were co-infected with HIV (41 (63%) were on anti-retroviral therapy (ARVs)) and hepatitis B respectively. In total, 116 were viraemic, median viral load of 5.7 (Interquartile range (IQR); 4.0-6.3) log iU/ml (75 (68.2%) were genotype 1a, 35 (31.8%) genotype 4a). The median alanine transaminase (ALT) (iU/l), aspartate transaminase (AST) (iU/l) and gamma-glutamyl transferase (GGT) (iU/l) were 35 (IQR; 23-51), 46 (32-57) and 69 (35-151) respectively. For the quantification of HCV RNA, serum HCVcAg had a sensitivity at 99.1% and a specificity at 94.1%, with an area under the receiver operating curve (AUROC) at 0.99 (95% CI 0.98-1.00). DBS HCVcAg had a sensitivity of 76.1% and a specificity of 97.3%, with an AUROC of 0.87 (95% CI 0.83-0.92). HCVcAg performance did not differ by HIV co-infection or HCV genotype. Conclusions Our study suggests that HCVcAg testing in serum is an excellent alternative to HCV polymerase chain reaction in Africa. Although HCVcAg detection and quantification in DBS has a reduced sensitivity, its specificity and accuracy are good and it could therefore be used for scaling up HCV testing and care in resource-limited African settings.


Assuntos
Teste em Amostras de Sangue Seco/métodos , Hepacivirus/isolamento & purificação , Hepatite C/diagnóstico , Proteínas do Core Viral/análise , Adulto , Feminino , Genótipo , Hepacivirus/genética , Hepacivirus/fisiologia , Hepatite C/sangue , Hepatite C/virologia , Antígenos da Hepatite C/análise , Antígenos da Hepatite C/genética , Antígenos da Hepatite C/metabolismo , Humanos , Masculino , Filogenia , RNA Viral/genética , Sensibilidade e Especificidade , Tanzânia , Proteínas do Core Viral/genética , Proteínas do Core Viral/metabolismo , Carga Viral
15.
Anal Chim Acta ; 982: 193-199, 2017 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-28734359

RESUMO

Biosensor development requires comprehensive research for establishing the optimal bioassay conditions that determine the final kinetics, sensitivity and specificity. Different systems have been developed to study bioreceptor-target interactions but they often have drawbacks, such as long hands-on time, low throughput, high sample consumption and high cost. In this work, the potential of the novel microfluidic Evalution™ platform has been evaluated for developing sandwich-based assays in a fast and high-throughput fashion. An immunoassay for the detection of influenza A nucleoprotein was used as a model system. Exploiting the platform's unique features, various typical bioassay parameters (e.g. aspecific binding between assay components, different reagent concentrations and incubation times) were tested for three capture antibodies in a simple and fast manner (2 runs of 80 min). The selected conditions, giving the highest signal-to-noise ratio, were directly employed on the same platform to detect nucleoprotein in buffer and nasopharyngeal swabs. Two antibodies with a higher dissociation constant (Ab11 and Ab12) required longer incubation times (60 min) for sensitive detection (limit of detection (LOD) of 0.48 and 0.26 ng mL-1, respectively) compared to an antibody with lower dissociation constant (LOD of 0.04 ng mL-1 for Ab66 within 30 min). Moreover, one antibody (Ab12) showed limited capacity to capture nucleoprotein directly in sample matrix. The obtained results were in accordance with previous studies performed on an ELISA and SPR platform with the same antibodies. This positions the Evalution™ platform as a reliable platform for fast and multiplex analysis of antibodies' performance both in buffer and complex sample matrices.


Assuntos
Anticorpos/análise , Imunoensaio , Microfluídica/métodos , Ensaio de Imunoadsorção Enzimática , Proteínas do Core Viral/análise
16.
Lab Chip ; 17(12): 2095-2103, 2017 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-28534926

RESUMO

We report an asymmetric immunoaggregation assay for rapid, label-free, and sub-picomolar protein detection. Asymmetric immunoaggregated beads (AIBs) are formed when binding occurs between 1 µm magnetic (MG) and 2.8 µm polystyrene (PS) beads coated with specific antibodies for a target antigen. Detection of such aggregation is achieved by optical monitoring of AIBs in a flow under an external magnetic field. AIBs are attracted to the upper surface of the microchannel by a magnetic field and made to slide along the surface by a flow drag force. This sliding behavior is in contrast with other particles such as MG and PS beads; while attracted MG beads hardly slide due to their small size, PS beads quickly move with the flow due to the lack of magnetism. Sliding AIBs are optically monitored in a designated sensing area in the microchannel. A custom-built program code is used for counting the AIBs and further analysis of parameters such as velocity and number distributions that are correlated with target concentrations. The detection range from 54 pg mL-1 to 54 ng mL-1 is demonstrated for the influenza type A H1N1 nucleoprotein (NP). This immunosensing system is simple, highly sensitive, and capable of quantitative detection of antigens in a single test without fluorescent or enzyme labeling, hence is useful for the rapid detection of biomarkers in clinical and biomedical applications.


Assuntos
Separação Imunomagnética , Técnicas Analíticas Microfluídicas , Desenho de Equipamento , Processamento de Imagem Assistida por Computador/métodos , Separação Imunomagnética/instrumentação , Separação Imunomagnética/métodos , Vírus da Influenza A Subtipo H1N1 , Limite de Detecção , Técnicas Analíticas Microfluídicas/instrumentação , Técnicas Analíticas Microfluídicas/métodos , Proteínas do Nucleocapsídeo , Proteínas de Ligação a RNA/análise , Gravação em Vídeo , Proteínas do Core Viral/análise
17.
J Virol Methods ; 243: 142-145, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28189584

RESUMO

A gold nanoparticle probe-based assay (GNPA) was developed for ultrasensitive detection of Hepatitis C virus (HCV) core antigen. In the GNPA, after anti-HCV core antigen polyclonal antibodies and single-stranded barcode signal DNA were labeled on gold nanoparticle probe (NP), DNA enzyme was used to degrade the unbound barcode DNAs. The anti-HCV core antigen monoclonal antibodies were coated on magnetic microparticles probe (MMP). Then the NP-HCV core antigen-MMP sandwich immuno-complex was formed when the target antigen protein was added and captured. Magnetically separated, the immuno-complex containing the single-stranded barcode signal DNA was characterized by TaqMan probe based real-time fluorescence PCR. A detection limit of 1 fg/ml was determined for the HCV core antigen which is magnitude greater than that of ELISA (2ng/ml). The coefficients of variation (CV) of intra-assay and inter-assay respectively ranged from 0.22-2.62% and 1.92-3.01%. The improved GNPA decreased the interference of unbound barcode DNAs and may be an new way for HCV core antigen detection.


Assuntos
Antígenos Virais/análise , Ouro , Hepacivirus/isolamento & purificação , Hepatite C/diagnóstico , Imunoensaio/métodos , Nanopartículas , Proteínas do Core Viral/análise , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Anal Chem ; 88(17): 8450-8, 2016 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-27487722

RESUMO

Flu is caused by the influenza virus that, due to mutations, keeps our body vulnerable for infections, making early diagnosis essential. Although immuno-based diagnostic tests are available, they have low sensitivity and reproducibility. In this paper, the prospect of detecting influenza A virus using digital ELISA has been studied. To appropriately select bioreceptors for this bioassay, seven commercial antibodies against influenza A nucleoprotein were methodically tested for their reactivity and binding affinity. The study has been performed on two markedly different platforms, being an enzyme-linked immunosorbent assay and a surface plasmon resonance system. The selected antibodies displayed completely different behavior on the two platforms and in various assay configurations. Surprisingly, the antibodies that showed overall good reactivity on both platforms had the highest dissociation constant among the tested antibodies, suggesting that, although important, binding affinity is not the only parameter to be considered when selecting antibodies. Moreover, only one antibody had the capacity to capture the nucleoprotein directly in lysis buffer used for releasing this viral protein, which might pose a huge advantage when developing assays with a fast time-to-result. This antibody was implemented on an in-house developed digital ELISA platform for ultrasensitive detection of recombinant nucleoprotein, reaching a detection limit of 4 ± 1 fM in buffer and 10 ± 2 fM in 10-fold diluted nasopharyngeal swabs, which is comparable to currently available fast molecular detection techniques. These results point to a great potential for ultrasensitive immuno-based influenza detection.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Vírus da Influenza A/química , Proteínas de Ligação a RNA/análise , Proteínas do Core Viral/análise , Proteínas do Nucleocapsídeo , Proteínas Recombinantes/análise
19.
Biomed Microdevices ; 17(3): 9951, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25860669

RESUMO

Integrating nanotechnology into useable devices requires a combination of bottom up and top down methodology. Often the techniques to measure and control these different components are entirely different, so methods that can analyse the nanoscale component in situ are of increasing importance. Here we describe a strategy that employs a self-assembling monolayer of engineered protein chimeras to display an array of oriented antibodies (IgG) on a microelectronic device for the label free detection of influenza nucleoprotein. The structural and functional properties of the bio-interface were characterised by a range of physical techniques including surface plasmon resonance, quartz-crystal microbalance and neutron reflectometry. This combination of methods reveals a 13.5 nm thick engineered-monolayer that (i) self-assembles on gold surfaces, (ii) captures IgG with high affinity in a defined orientation and (iii) specifically recognises the influenza A nucleoprotein. Furthermore we also show that this non-covalent self-assembled structure can render the dissociation of bound IgG irreversible by chemical crosslinking in situ without affecting the IgG function. The methods can thus describe in detail the transition from soluble engineered molecules with nanometre dimensions to an array that demonstrates the principles of a working influenza sensor.


Assuntos
Imunoensaio/instrumentação , Influenza Humana/metabolismo , Sistemas Microeletromecânicos/instrumentação , Engenharia de Proteínas/métodos , Proteínas de Ligação a RNA/análise , Ressonância de Plasmônio de Superfície/instrumentação , Proteínas do Core Viral/análise , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Proteínas do Nucleocapsídeo , Proteínas de Ligação a RNA/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Coloração e Rotulagem , Proteínas do Core Viral/química
20.
Viruses ; 7(4): 2030-56, 2015 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-25903832

RESUMO

There is a need for safe and broadly effective anti-HCV agents that can cope with genetic multiplicity and mutations of the virus. In this study, humanized-camel VHHs to genotype 3a HCV serine protease were produced and were linked molecularly to a cell penetrating peptide, penetratin (PEN). Human hepatic (Huh7) cells transfected with the JFH-1 RNA of HCV genotype 2a and treated with the cell penetrable nanobodies (transbodies) had a marked reduction of the HCV RNA intracellularly and in their culture fluids, less HCV foci inside the cells and less amounts of HCV core antigen in culture supernatants compared with the infected cells cultured in the medium alone. The PEN-VHH-treated-transfected cells also had up-regulation of the genes coding for the host innate immune response (TRIF, TRAF3, IRF3, IL-28B and IFN-ß), indicating that the cell penetrable nanobodies rescued the host innate immune response from the HCV mediated-suppression. Computerized intermolecular docking revealed that the VHHs bound to residues of the protease catalytic triad, oxyanion loop and/or the NS3 N-terminal portion important for non-covalent binding of the NS4A protease cofactor protein. The so-produced transbodies have high potential for testing further as a candidate for safe, broadly effective and virus mutation tolerable anti-HCV agents.


Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Hepacivirus/fisiologia , Anticorpos Anti-Hepatite C/farmacologia , Anticorpos de Domínio Único/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Animais , Camelus , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Linhagem Celular , Peptídeos Penetradores de Células , Citocinas/biossíntese , Portadores de Fármacos/metabolismo , Perfilação da Expressão Gênica , Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/genética , Hepatócitos/virologia , Humanos , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Ligação Proteica , RNA Viral/análise , Análise de Sequência de DNA , Anticorpos de Domínio Único/genética , Transfecção , Proteínas do Core Viral/análise
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