نتایج جستجو برای: hbv escape mutations

تعداد نتایج: 214596  

Journal: :Intervirology 2006
Syed Naqui Kazim Shiv Kumar Sarin Barjesh Chander Sharma Luqman Ahmad Khan Seyed Ehtesham Hasnain

BACKGROUND Besides vaccine escape or immune escape hepatitis B virus (HBV) mutants, naturally occurring and drug-induced mutations have been reported in the surface gene (S-gene) of HBV. AIM To investigate the frequency and profile of naturally occurring S-gene mutants and the influence of long-term lamivudine therapy in patients with chronic hepatitis B (CHB). MATERIALS AND METHODS 57 pati...

Journal: :Gut 1999
P L Shields A Owsianka W F Carman E Boxall S G Hubscher J Shaw K O'Donnell E Elias D J Mutimer

CASE REPORT A patient is described who developed hepatitis B virus (HBV) reinfection five months following liver transplantation. Failure of hepatitis B immunoglobulin prophylaxis was associated with the emergence of mutations. HBV gene sequencing identified nucleotide substitutions associated with amino acid changes, one within the major hydrophilic region (MHR) of the HBV surface antigen at a...

1999
P L Shields D J Mutimer

Case report—A patient is described who developed hepatitis B virus (HBV) reinfection five months following liver transplantation. Failure of hepatitis B immunoglobulin prophylaxis was associated with the emergence of mutations. HBV gene sequencing identified nucleotide substitutions associated with amino acid changes, one within the major hydrophilic region (MHR) of the HBV surface antigen at a...

Journal: :jundishapur journal of microbiology 0
sajad shahmoradi hepatitis b molecular laboratory, department of virology-school of public health, tehran university of medical sciences, tehran, ir iran mohammad hossein somi liver and gastrointestinal disease research center, eastern azarbyjan university of medical sciences, tabriz, ir iran mehdi norouzi hepatitis b molecular laboratory, department of virology-school of public health, tehran university of medical sciences, tehran, ir iran seyed moayed alavian baqiyatallah university of medical sciences, baqiyatallah research center for gastroenterology and liver disease, tehran, ir iran hadi karimzadeh hepatitis b molecular laboratory, department of virology-school of public health, tehran university of medical sciences, tehran, ir iran ramin rahimnia hepatitis b molecular laboratory, department of virology-school of public health, tehran university of medical sciences, tehran, ir iran

conclusions the distribution of amino acid mutations as well as the ratio between missense and silent nucleotide mutations (dn/ds) showed that a narrowly focused immune pressure had already been on the surface protein (especially ctl epitopes) which led to the emergence of escape mutants in these patients who were in tolerance phase of chronicity. materials and methods the surface genes from 17...

2014
Giovanni Galati Antonio De Vincentis Umberto Vespasiani-Gentilucci Paolo Gallo Donatella Vincenti Maria Carmela Solmone Chiara Dell’Unto Antonio Picardi

BACKGROUND Some reports have documented the coexistence of Hepatitis B surfage Antigen (HBsAg) and anti-HBsAg antibodies (HBsAb) in patients with chronic hepatitis B (CHB), often in the absence of amino acid substitutions in the HBsAg sequences of the Hepatitis B Virus (HBV) genome able to explain an immunological escape variant.HBV genome has a very compact coding organization, with four parti...

Journal: :Iranian journal of allergy, asthma, and immunology 2013
Fatemeh Ramezani Mehdi Norouzi Gholam Reza Sarizade Vahdat Poortahmasebi Ebrahim Kalantar Lars Magnius Helen Norder Esteban Domingo Seyed Mohammad Jazayeri

Mutations in the human hepatitis B virus (HBV) genome contribute to its escape from host immune surveillance and result in persistent infections. The aim of this study was to characterize the molecular variations of the surface gene and protein in chronically-infected patients from the southern part of Iran. The surface genes from 12 HBV chronic carriers were amplified, sequenced and subsequent...

Journal: :acta medica iranica 0
payam dindoost department of gastroenterology, middle east liver diseases center (meld centers), tehran, iran. narges chimeh department of psychiatry, family research institute, shahid beheshti university, tehran, iran. blain f hollinger department of gastroenterology, baylor college of medicine one baylor plaza, houston, usa. esmaeil saberfar department of virology, bayerpaul (bp) vaccines and pharmaceutical company, tehran, iran. mehdi norouzi department of virology, faculty of public health, tehran university of medical sciences, tehran, iran. seyed mohammad jazayeri department of virology, faculty of public health, tehran university of medical sciences, tehran, iran.

occult hepatitis b (ohb), or persistent hepatitis b virus (hbv) viremia in surface-antigen-hbsag-negative patients, has been recognized as a medical concern during the last decade. the exact magnitude, pathogenesis and clinical relevance of ohb are unclear. this review organizes the published data on ohb and presents an overview of the current hypotheses on ohb's pathogenesis and clinical relev...

Background and Objective: The drug resistance mutations are key elements in the failure of long-term treatment of Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) infections. The mutation in the YMDD motif in the P gene of HBV is the most critical factor in antiviral drug (especially lamivudine) resistance. This study aimed to assess the YMDD motif and other polymerase gene mutati...

Journal: :jundishapur journal of microbiology 0
chiman karami department of virology, ahvaz jundishapur university of medical sciences, ahvaz, iran ahmad h adli department of virology, golestan university of medical sciences, gorgan, iran sareh zhand department of biotechology, golestan university of medical sciences, gorgan, iran alijan tabarraei department of microbiology, golestan university of medical sciences, gorgan, iran reza talei department of microbiology, lorestan university of medical sciences, khorramabad, iran mohsen saeidi stem cell research center, golestan university of medical sciences, gorgan, iran

background co-infection with human immunodeficiency virus (hiv) and hepatitis b virus (hbv) is common due to shared routes of transmission, as reported approximately 10% of 33 million hiv-infected patients worldwide are chronically infected with hbv. mutations of hbsag especially within the “a” determinant could alter the antigenicity of the protein, causing failure of hbsag neutralization and ...

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