Συμβολή στη μελέτη των μεταλλαγών της πρωτεΐνης του πυρήνα του ιού της ηπατίτιδας Β και της αντιγονικής εκφράσεως σε ασθενείς με χρονία HBV λοίμωξη

2013 ◽  
Author(s):  
Ειρήνη Ράπτη
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Intracellular Cytokine Staining ◽  
Intracellular Cytokine ◽  
B Virus ◽  
Ifn Γ

Κυτταρικές ανοσιακές αντιδράσεις στην HBeAg αρνητική χρονία ηπατίτιδα ΒΣκοπός: Η ανοσοπαθογένεια της HBeAg αρνητικής χρονίας ηπατίτιδας Β (ΧΗΒ) δεν έχει μελετηθεί επαρκώς. Σκοπός λοιπόν της παρούσας μελέτης ήταν η αποτύπωση των κυτταρικών ανοσιακών αντιδράσεων στη μορφή αυτή της ΧΗΒ.Ασθενείς και μέθοδοι: Μελετήσαμε τις κυτταρικές ανοσιακές αντιδράσεις των περιφερικών λεμφοκυττάρων χρησιμοποιώντας λεμφοκυτταρικές καλλιέργειες, μεθόδους ενδοκυττάριας χρώσης κυττοκινών (intracellular cytokine staining (ICS) καθώς και μέτρησης της παραγωγής ιντερφερόνης-γ με τη μέθοδο ELISPOT μετά από μη ειδική και ειδική διέγερση με ολικές πρωτεΐνες του ιού της ηπατίτιδας Β (Hepatitis B Virus, HBV) αλλά και συνθετικά πεπτίδια.Τριάντα ασθενείς με HBeAg αρνητική ΧΗΒ, έντεκα ασυμπτωματικοί φορείς, εννέα ασθενείς με οξεία ηπατίτιδα Β και εικοσιδύο υγιείς μάρτυρες εισήχθησαν στη μελέτη.Αποτελέσματα: Οι ασθενείς με HBeAg (-) ΧΗΒ παρουσίασαν αυξημένο ποσοστό διεγερμένων περιφερικών CD8+ Τ-λεμφοκυττάρων και παράλληλα αυξημένο πολλαπλασιασμό των περιφερικών CD4 λεμφοκυττάρων μετά από in vitro διέγερση με αλληλοεπικαλυπτόμενα πεπτίδια του πυρηνοκαψιδίου του HBV καθώς και ένα πεπτίδιο του φακέλλου του HBV (HBs 182-191 aa), αντίδραση ομοιάζουσα σε ένταση με αυτή των ασθενών με οξεία ηπατίτιδα Β. Με τη χρήση ενδοκυττάριας χρώσης κυττοκινών (ICS), διαπιστώσαμε στην HBeAg (-) ΧΗΒ έναν διεγερμένο πληθυσμό Τ-λεμφοκυττάρων με παραγωγή IFN-γ (CD4+ και CD8+), μετά από μη ειδική διέγερση συγκριτικά με όλες τις άλλες ομάδες ασθενών και υγιών μαρτύρων. Επιπλέον οι ασθενείς με HBeAg(-) ΧΗΒ καθώς και αυτοί με οξεία ηπατίτιδα Β παρουσίασαν έναν εξίσου αυξημένο αριθμό ειδικών για το πυρηνοκαψίδιο του ιού (HBcore) T λεμφοκυττάρων, όπως μετρήθηκε με τις μεθόδους υπολογισμού της IFN-γ. Αντίθετα, ενώ οι ασυμπτωματικοί HBsAg φορείς είχαν ελάχιστες αντιδράσεις πολλαπλασιασμού των CD4+ λεμφοκυττάρων συνολικά όμως διατηρούσαν αυξημένο αριθμό διεγερμένων Τ-λεμφοκυττάρων ειδικών για την πρωτείνη του φακέλλου (όπως μετρήθηκε με ICS). Συμπεράσματα: Η μελέτη αυτή κατέδειξε ότι οι συνολικές CD4+ T λεμφοκυτταρικές αντιδράσεις των ασθενών με HBeAg (-) ΧΗΒ είναι συγκρίσιμες με αυτές των ασθενών με οξεία ηπατίτιδα Β, ενώ στους ασυμπτωματικούς HBsAg φορείς παρά τις περιορισμένες CD4+αντιδράσεις, η ικανότητα διέγερσης των περιφερικών Τ-λεμφοκυττάρων διατηρείται.

scholarly journals Cytokine-Sensitive Replication of Hepatitis B Virus in Immortalized Mouse Hepatocyte Cultures

2002 ◽  
Vol 76 (11) ◽  
pp. 5646-5653 ◽  
Author(s):  
Valérie Pasquetto ◽  
Stefan F. Wieland ◽  
Susan L. Uprichard ◽  
Marco Tripodi ◽  
Francis V. Chisari
Keyword(s):  
Gene Expression ◽  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Intracellular Signaling ◽  
Growth Factor Receptor ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
B Virus ◽  
Ifn Γ

ABSTRACT We have previously shown that alpha/beta interferon (IFN-α/β) and gamma interferon (IFN-γ) inhibit hepatitis B virus (HBV) replication by eliminating pregenomic RNA containing viral capsids from the hepatocyte. We have also shown that HBV-specific cytotoxic T lymphocytes that induce IFN-γ and tumor necrosis factor alpha (TNF-α) in the liver can inhibit HBV gene expression by destabilizing preformed viral mRNA. In order to further study the antiviral activity of IFN-α/β, IFN-γ, and TNF-α at the molecular level, we sought to reproduce these observations in an in vitro system. Accordingly, hepatocytes were derived from the livers of HBV-transgenic mice that also expressed the constitutively active cytoplasmic domain of the human hepatocyte growth factor receptor (c-Met). Here, we show that the resultant well-differentiated, continuous hepatocyte cell lines (HBV-Met) replicate HBV and that viral replication in these cells is efficiently controlled by IFN-α/β or IFN-γ, which eliminate pregenomic RNA-containing capsids from the cells as they do in the liver. Furthermore, we demonstrate that IFN-γ, but not IFN-α/β, is capable of inhibiting HBV gene expression in this system, especially when it acts synergistically with TNF-α. These cells should facilitate the analysis of the intracellular signaling pathways and effector mechanisms responsible for these antiviral effects.

Green tea extract and its major component epigallocatechin gallate inhibits hepatitis B virus in vitro

2008 ◽  
Vol 78 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Jun Xu ◽  
Jue Wang ◽  
Fei Deng ◽  
Zhihong Hu ◽  
Hualin Wang
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Green Tea ◽  
Epigallocatechin Gallate ◽  
Green Tea Extract ◽  
B Virus ◽  
Tea Extract

scholarly journals Epitope–Paratope Interaction of a Neutralizing Human Anti-Hepatitis B Virus PreS1 Antibody That Recognizes the Receptor-Binding Motif

Vaccines ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 754
Author(s):  
Jisu Hong ◽  
Youngjin Choi ◽  
Yoonjoo Choi ◽  
Jiwoo Lee ◽  
Hyo Jeong Hong
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Receptor Binding ◽  
Neutralizing Antibody ◽  
Hbv Infection ◽  
Binding Motif ◽  
Alanine Scanning Mutagenesis ◽  
B Virus ◽  
Complementarity Determining Regions

Hepatitis B virus (HBV) is a global health burden that causes acute and chronic hepatitis. To develop an HBV-neutralizing antibody that effectively prevents HBV infection, we previously generated a human anti-preS1 monoclonal antibody (1A8) that binds to genotypes A–D and validated its HBV-neutralizing activity in vitro. In the present study, we aimed to determine the fine epitope and paratope of 1A8 to understand the mechanism of HBV neutralization. We performed alanine-scanning mutagenesis on the preS1 (aa 19–34, genotype C) and the heavy (HCDR) and light (LCDR) chain complementarity-determining regions. The 1A8 recognized the three residues (Leu22, Gly23, and Phe25) within the highly conserved receptor-binding motif (NPLGFFP) of the preS1, while four CDR residues of 1A8 were critical in antigen binding. Structural analysis of the epitope–paratope interaction by molecular modeling revealed that Leu100 in the HCDR3, Ala50 in the HCDR2, and Tyr96 in the LCDR3 closely interacted with Leu22, Gly23, and Phe25 of the preS1. Additionally, we found that 1A8 also binds to the receptor-binding motif (NPLGFLP) of infrequently occurring HBV. The results suggest that 1A8 may broadly and effectively block HBV entry and thus have potential as a promising candidate for the prevention and treatment of HBV infection.

scholarly journals Phosphorothioate Di- and Trinucleotides as a Novel Class of Anti-Hepatitis B Virus Agents

2004 ◽  
Vol 48 (6) ◽  
pp. 2199-2205 ◽  
Author(s):  
Radhakrishnan P. Iyer ◽  
Yi Jin ◽  
Arlene Roland ◽  
John D. Morrey ◽  
Samir Mounir ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Nucleoside Analogs ◽  
Hbv Dna ◽  
Parallel Synthesis ◽  
Hbv Replication ◽  
Long Term Treatment ◽  
B Virus ◽  
Dna Strand

ABSTRACT Several nucleoside analogs are under clinical development for use against hepatitis B virus (HBV). Lamivudine (3TC), a nucleoside analog, and adefovir dipivoxil (ADV), an acyclonucleotide analog, are clinically approved. However, long-term treatment can induce viral resistance, and following the cessation of therapy, viral rebound is frequently observed. There continues to be a need for new antiviral agents with novel mechanisms of action. A library of more than 600 di- and trinucleotide compounds synthesized by parallel synthesis using a combinatorial strategy was screened for potential inhibitors of HBV replication using the chronically HBV-producing cell line 2.2.15. Through an iterative process of synthesis, lead optimization, and screening, three analogs were identified as potent inhibitors of HBV replication: dinucleotides ORI-7246 (drug concentration at which a 10-fold reduction of HBV DNA was observed [EC90], 1.4 μM) and ORI-9020 (EC90, 1.2 μM) and trinucleotide ORI-7170 (EC90, 7.2 μM). These analogs inhibited the replication of both strands of HBV DNA. No suppression of HBV protein synthesis or intracellular core particle formation by these analogs was observed. No inhibition of HBV DNA strand elongation by the analogs or their 5′-triphosphate versions was apparent in in vitro polymerase assays. Although the exact mechanism of action is not yet identified, present data are consistent with an inhibition of the HBV reverse transcriptase-directed priming step prior to elongation of the first viral DNA strand. In transient-transfection assays, these analogs inhibited the replication of 3TC-resistant HBV. Synergistic interactions in combination treatments between the analogs and either 3TC or ADV were observed. These compounds represent a novel class of anti-HBV molecules and warrant further investigation as potential therapeutic agents.

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