Search results for "nonstructural proteins"
showing 10 items of 100 documents
Prevalence of Single and Multiple Natural NS3, NS5A and NS5B Resistance-Associated Substitutions in Hepatitis C Virus Genotypes 1-4 in Italy
2018
AbstractNatural resistance-associated substitutions (RASs) are reported with highly variable prevalence across different HCV genotypes (GTs). Frequency of natural RASs in a large Italian real-life cohort of patients infected with the 4 main HCV-GTs was investigated. NS3, NS5A and NS5B sequences were analysed in 1445 HCV-infected DAA-naïve patients. Sanger-sequencing was performed by home-made protocols on 464 GT1a, 585 GT1b, 92 GT2c, 199 GT3a, 16 GT4a and 99 GT4d samples. Overall, 20.7% (301/1455) of patients showed natural RASs, and the prevalence of multiclass-resistance was 7.3% (29/372 patients analysed). NS3-RASs were particularly common in GT1a and GT1b (45.2-10.8%, respectively), mai…
Multiclass HCV resistance to direct-acting antiviral failure in real-life patients advocates for tailored second-line therapies
2017
Background & Aims: Despite the excellent efficacy of direct-acting antivirals (DAA) reported in clinical trials, virological failures can occur, often associated with the development of resistance-associated substitutions (RASs). This study aimed to characterize the presence of clinically relevant RASs to all classes in real-life DAA failures. Methods: Of the 200 virological failures that were analyzed in 197 DAA-treated patients, 89 with pegylated-interferon+ribavirin (PegIFN+RBV) and 111 without (HCV-1a/1b/1g/2/3/4=58/83/1/6/24/25; 56.8% treatment experienced; 65.5% cirrhotic) were observed. Sanger sequencing of NS3/NS5A/NS5B was performed by home-made protocols, at failure (N= 200) and w…
NS5A gene analysis by next generation sequencing in HCV nosocomial transmission clusters of HCV genotype 1b infected patients
2019
Background: The aim of the study was to investigate the intra-host variability through next-generation-sequencing (NGS) of the NS5A-gene in nosocomial transmission-clusters observed in two Italian hospitals among hepatitis C virus (HCV)-genotype-1b infected patients. Methods: HCV-sequencing was performed by Sanger-sequencing (NS3 + NS5A + NS5B) and by NGS (NS5A, MiSeq-Illumina) in 15 HCV-1b infected patients [five acute with onco-hematologic-disease and 10 (4/6 acute/chronic) with &beta
Vascular Leakage in Severe Dengue Virus Infections: A Potential Role for the Nonstructural Viral Protein NS1 and Complement
2006
Background Vascular leakage and shock are the major causes of death in patients with dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Thirty years ago, complement activation was proposed to be a key underlying event, but the cause of complement activation has remained unknown. Methods The major nonstructural dengue virus (DV) protein NS1 was tested for its capacity to activate human complement in its membrane-associated and soluble forms. Plasma samples from 163 patients with DV infection and from 19 patients with other febrile illnesses were prospectively analyzed for viral load and for levels of NS1 and complement-activation products. Blood and pleural fluids from 9 patient…
HCV-1b intra-subtype variability: Impact on genetic barrier to protease inhibitors
2013
Abstract Due to error-prone RNA polymerase and the lack of proofreading mechanisms, to the spread worldwide and probable long-term presence in human population, HCV showed a high degree of inter- and intra-subtype genetic variability. Protease inhibitors (PIs), a new class of drugs, have been designed specifically on the HCV genotype 1 NS3 protease three-dimensional structure. The viral genetic barrier limits the efficacy of PIs, and fourteen loci in the HCV NS3 gene are involved in resistance to PIs. A sensitive method (15 UI/ml) for study the HCV genetic profile of 125 strains from patients naive to PIs, was developed through the use of new degenerate primers for subtype 1b. We observed t…
Viral proteins VP2, VP6, and NSP2 are strongly precipitated by serum and fecal antibodies from children with rotavirus symptomatic infection
1998
Rotavirus-specific IgA has been correlated with immune protection against rotavirus reinfection and symptomatic disease. Systemic and mucosal antibody responses were determined by an enzyme-linked immunosorbent assay in 11 infants with severe rotavirus gastroenteritis. Geometric mean titers of antirotavirus serum IgG and IgA antibodies were significantly higher during the convalescence of the disease (P < 0.001 vs. acute-phase titers). Rotavirus-specific fecal sIgA antibodies increased 4 times during the convalescence in 9 (81.8%) children (P < 0.001). The serum IgG and IgA antibody and fecal sIgA antibody responses to individual rotavirus polypeptides were characterized by radioimmunopreci…
Phylogenetic reconstruction of HCV genotype 1b dissemination in a small city centre: The Camporeale model
2008
Several seroepidemiological population-based surveys carried out in Italy have shown a high prevalence of hepatitis C virus (HCV) infection. Camporeale (CP), a small Sicilian town with a 10.4% prevalence of HCV mostly genotype 1b, probably represents a specific context, since intravenous drug addiction, and sexual promiscuity are almost absent. In order to reconstruct the pattern of introduction and diffusion of HCV in this ecological niche, the NS5 genomic region of 72 HCV genotype 1 isolates (39 from CP and 33 collected throughout Sicily) was amplified and sequenced. Sequences were aligned and analyzed by BioEdit, PAUP and BEAST, and their molecular evolution compared. Thirty-eight HCV ge…
Resistance analysis and treatment outcomes in hepatitis C virus genotype 3-infected patients within the Italian network VIRONET-C
2021
Aim: This study aimed to investigate the role of resistance-associated substitutions (RASs) to direct-acting-antivirals (DAAs) in HCV genotype 3 (GT3). Methods: Within the Italian VIRONET-C network, a total of 539 GT3-infected patients (417 DAA-naïve and 135 DAA-failures, of them, 13 at both baseline and failure) were analysed. Sanger sequencing of NS3/NS5A/NS5B was performed following home-made protocols. Results: The majority of patients were male (79.4%), 91.4% were injection drug users, 49.3% were cirrhotic and 13.9% were HIV co-infected. Phylogenetic analysis classified sequences as GT3a-b-g-h (98%-0.4%-0.2%-1.2%) respectively. Overall, 135 patients failed a DAA regimen: sofosbuvir (SO…
ISDR pattern and evolution in patients with chronic hepatitis C treated with standard or Peg-IFN plus ribavirin
2003
The aim of the study was to characterize the interferon sensitivity determining region (ISDR) mutation pattern and its changes at 4 weeks of treatment in a population of patients infected with hepatitis C virus (HCV) genotype 1b receiving standard or PEG-IFN plus ribavirin (RBV), to find possible early correlates of therapy outcome.Forty-five patients with chronic hepatitis due to HCV 1b were treated by PEG-IFN-α2b (n=23) or IFN-α2b (n=22) plus RBV 1000–1200 mg/day. They were classified 24 weeks after stopping therapy as sustained responders (SR), relapsers (REL) or non-responders (NR). Sixteen patients were SR, 12 REL and 17 NR. ISDR mutations were evaluated by direct sequencing at baselin…
Generation of immune responses against hepatitis C virus by dendritic cells containing NS5 protein-coated microparticles.
2009
ABSTRACTDendritic cells (DCs) internalize and process antigens as well as activate cellular immune responses. The aim of this study was to determine the capacity of DCs that contain antigen-coated magnetic beads to induce immunity against the nonstructural hepatitis C virus (HCV) antigen 5 (NS5). Splenocytes derived from Fms-like tyrosine kinase receptor 3 (Flt3) ligand-pretreated BALB/c mice were incubated with magnetic beads coated with HCV NS5, lipopolysaccharide (LPS), and/or anti-CD40; purified; and used for immunization. Cellular immunity was measured using cytotoxic T-lymphocyte (CTL) and T-cell proliferation assays, intracellular cytokine staining, and a syngeneic tumor challenge us…