Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Monoclonal antibody 2F10 is an "internal-image" anti-idiotype (anti-id) antibody capable of mimicking the group-specific "a" determinant of human hepatitis B surface antigen (HBsAg). By mRNA sequencing and computer-assisted molecular modeling of monoclonal antibody 2F10, we identified a 15-amino acid region of the heavy-chain hypervariable region that has partial residue homology with sequences of the "a" determinant epitopes of HBsAg. We have established that a linear 15-mer peptide from a contiguous region on the anti-id antibody can (i) generate anti-HBsAg-specific antibodies when injected into mice, (ii) prime murine lymph node cells for in vitro HBsAg-specific T-cell proliferative responses, and (iii) stimulate in vitro human CD4+ T cells that were primed in vivo to HBsAg by natural infection with hepatitis B virus or vaccination with a commercially available HBsAg vaccine. Significantly, this peptide could also stimulate CD4+ T cells of human hepatitis B virus carriers. We conclude that a 15-mer peptide derived from the anti-id sequence can duplicate the B- and T-cell stimulatory activity of the intact anti-id antibody and the antigen that is mimicked, HBsAg.
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PMID:Molecular mimicry of hepatitis B surface antigen by an anti-idiotype-derived synthetic peptide. 136 Dec 31

A 21-mer oligodeoxynucleotide complementary to the polyadenylation signal for human hepatitis B virus (HBV) was complexed to a soluble DNA-carrier system that is targetable to hepatocytes via asialoglycoprotein receptors present on those cells. A cell line, HepG2 (2.2.15) that possesses asialoglycoprotein receptors and is permanently transfected with hepatitis B virus (ayw subtype) was exposed to complexed antisense DNA or controls. In the presence of complexed antisense DNA, the concentration of hepatitis B surface antigen in medium was 80% lower than controls after 24 h. Furthermore, during the next 6 days, there was no significant increase in surface antigen concentration in the presence of complexed antisense DNA. The inhibition could be effectively blocked by competition with an excess of free asialoglycoprotein. Total protein synthesis remained unchanged by exposure to complexed antisense sequences under identical conditions. In addition, HBV DNA in the medium and cell layers after 24-h exposure to complexed antisense sequences was 80% lower than in controls. The data indicate that antisense oligonucleotides complexed by a soluble DNA-carrier system can be targeted to cells via asialoglycoprotein receptors resulting in specific inhibition of hepatitis B viral gene expression and replication.
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PMID:Specific inhibition of hepatitis B viral gene expression in vitro by targeted antisense oligonucleotides. 161 51

We developed a polymerase chain reaction assay for the direct detection of hepatitis B virus in paraffin-embedded liver tissue and applied this assay to determine whether hepatitis B virus DNA exists in livers with chronic hepatitis non-A, non-B. Fifty five liver biopsy samples were studied: 11 from patients with HBeAg-positive chronic hepatitis (paraffin-embedded) and 44 from patients with chronic hepatitis non-A, non-B (21 paraffin-embedded; 25 fresh frozen). Thirty three (75%) of the non-A, non-B cases were positive for hepatitis C virus antibodies. Approximately 1 to 10 ng of DNA was extracted from the paraffin-embedded tissue and amplified using oligonucleotide (23-mer) primers specific for the S gene (positions 261 to 692). The beta-globin gene was used as an internal control for sensitivity because this is a single copy gene and allows for relative quantification. In each of the chronic hepatitis B livers, the expected 432-base-pair amplification product for hepatitis B virus DNA and beta-globin gene product were both detected. On the other hand, in the 21 paraffin-embedded chronic hepatitis non-A, non-B livers, no hepatitis B virus DNA was detected, although beta-globin gene was observed in all. Furthermore, in all 25 frozen non-A, non-B livers, beta-globin gene was observed, but no hepatitis B virus band was seen. The limit of detection of hepatitis B virus DNA by this method was estimated to be one genomic copy of hepatitis B virus DNA per cell.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Detection of hepatitis B virus DNA in paraffin-embedded liver tissues in chronic hepatitis B or non-A, non-B, hepatitis using the polymerase chain reaction. 189 81

We investigated the major histocompatibility complex (MHC) class I-restricted presentation of an epitope of the hepatitis B virus small surface (S) antigen particle to cloned murine cytotoxic T lymphocytes (CTL). Efficient Ld-restricted presentation of the S28-39 epitope to CTL is observed in cells of different tissue origin pulsed in vitro, either with the antigenic S28-39 12-mer S-peptide, or with particulate S-antigen. The kinetics of epitope presentation differ in S-peptide-pulsed and in S-particle-pulsed cells: while a 15-min pulse with the antigenic peptide sensitizes targets for class I-restricted CTL lysis, presentation of S-particles requires 30-60 min to sensitize cells for CTL lysis. Uptake of antigenic material and active metabolism of the presenting cell are required for processing of S-particles, but not for sensitizing targets with S-peptides. Intracellular processing and presentation of S-particles is blocked in cells treated with chloroquine, NH4Cl, primaquine, or leupeptin, but not by treatment with cycloheximide or brefeldin A. This processing pathway operates efficiently in peptide-transporter-deficient, Ld-transfected T2 cells, revealing a novel endosomal/lysosomal processing pathway for class I-restricted presentation of peptides derived from exogenous S-particles.
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PMID:Hepatitis B virus small surface antigen particles are processed in a novel endosomal pathway for major histocompatibility complex class I-restricted epitope presentation. 753 71

We chose the 2.2. 15 cells as an in vitro cell culture assay system, and identified the surface antigen subtype of hepatitis B virus (HBV) DNA in the cells, by using the amplification of polymerase chain reaction and directed sequencing of amplified products. According to the result of the sequencing, a 16-mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASON) directed against the HBV U5-unique region was synthesized and then linked with two liver-targeting ligands. The galactosylated human serum albumin coupled poly-L-lysine and the galactosylated poly-L-lysine. The effect of different modifications of ASONs on the expression of HBV gene was compared by using the 2.2. 15 cells. In the same experimental conditions, the inhibitary effects of surface antigen (HBsAg) and antigen (HBeAg) by PS-ASON were 70% and 58% respectively, and those of HBsAg and HBeAg by ligand-PS-ASONs were 90%-96% and 78%-82%. In the same time, the amount of HBV NDA in culture supernatant and cells was depressed significantly. Thus, the ligands targeted ASON to the hepatocytes were more effective inhibitors of HBV gene expression. ASONs were effective and specific inhibitors of HBV replication and expression, caused the dose-dependent inhibition of viral proteins and had no effect on cellular alpha-fetoprotein synthesis and no cytotoxicity.
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PMID:[Inhibition of hepatitis B viral gene expression and replication in vitro by targeted antisense oligonucleotides]. 755 55

Residues 11 to 27 of the hepatitis B virus nucleocapsid antigen contain a cytotoxic T-cell epitope that is recognized by cytotoxic T cells from virtually all HLA-A2-positive patients with acute hepatitis B virus infection. Using panels of truncated and overlapping peptides, we now show that the optimal amino acid sequence recognized by cytotoxic T cells is a 10-mer (residues 18 to 27) containing the predicted peptide-binding motif for HLA-A2 and that this peptide can stimulate cytotoxic T cells able to recognize endogenously synthesized hepatitis B core antigen. Since patients with chronic hepatitis B virus infection fail to mount an efficient cytotoxic T-cell response to it, this epitope might serve as the starting point for the design of synthetic peptide-based immunotherapeutic strategies to terminate persistent viral infection.
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PMID:Definition of a minimal optimal cytotoxic T-cell epitope within the hepatitis B virus nucleocapsid protein. 768 Mar 91

In the murine system, we tested in vivo the immunogenicity of different preparations of the yeast-derived surface antigen (S-antigen or S-protein) of hepatitis B virus (HBV). Native S-protein molecules self-assemble into stable 22-nm particles. BALB/c mice immunized with low doses of native S-particles without adjuvants efficiently generated an H-2 class I-restricted CD8+ cytotoxic T lymphocyte (CTL) response, and developed easily detectable serum antibody titers against conformational determinants of the native S-particle or linear epitopes of the denatured S-protein. Disruption of S-particles with sodium dodecyl sulfate and beta-2-mercaptoethanol generated p24 S-monomers. Injection of an equal dose of S-monomers into mice efficiently primed CTL, but did not stimulate an antibody response against conformational or linear epitopes of the native or denatured S-protein. In vivo priming of CTL by S-particles or S-monomers required "endogenous" processing of the antigen because the injection of an equimolar (or higher) dose of an antigenic, S-derived 12-mer peptide into mice did not prime CTL. Native (particulate) or denatured (monomeric) S-antigen injected with mineral oil (incomplete Freund's adjuvant) or aluminum hydroxide failed to stimulate a CTL response. Hence, different preparations can be produced from a small protein antigen which specifically stimulate selected compartments of the immune system.
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PMID:Selective stimulation of murine cytotoxic T cell and antibody responses by particulate or monomeric hepatitis B virus surface (S) antigen. 818 20

The uptake and distribution of phosphorothioate oligodeoxynucleotides by human cells were studied using 35S-labeled 28-mer phosphorothioate oligodeoxycytidine [S-(dC)28]. Accumulation of intracellular S-(dC)28 was found to be higher in the carcinoma cells (grown in monolayers) than in the leukemia cells (grown in suspension culture). A hepatoma cell line transfected with hepatitis B virus, 2215, was chosen for further studies. The uptake of S-(dC)28 was partially dependent on temperature and energy. The intracellular concentration was significantly higher than that in the medium and the amount accumulated was dependent on the extracellular concentration. It appears that the uptake of S-(dC)28 involves mechanisms of both fluid-phase pinocytosis and adsorptive endocytosis. Neither oligonucleotides nor 5'-phosphorylated nucleotides inhibited S-(dC)28 uptake. Unlike horseradish peroxidase, which was primarily associated with endosomes once it was taken into the cell, S-(dC)28 was found to be present in both nuclear and cytoplasmic fractions. Efflux of S-(dC)28 from the cell was multiphasic; a trapping mechanism that could be due to a potent interaction of S-(dC)28 with cellular proteins was implicated. This trapping mechanism could be responsible for the lack of biological activity such as cytotoxicity and antisense activity of phosphorothioate oligodeoxynucleotides in some human cells.
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PMID:Cellular pharmacology of phosphorothioate homooligodeoxynucleotides in human cells. 842 68

The serum Ab response and the class I-restricted CTL response of C57BL/6 (H-2b) mice to hepatitis B (pre)core Ag (HBcAg, HBeAg) was studied. Injection of HBcAg particles without adjuvants into mice efficiently primed serum Ab responses but not CTL response. We constructed the expression plasmids pCMV-1/c and pCMV-1/e in which expression of HBcAg or HBeAg was driven by cytomegalovirus immediate early region promoter sequences. Stable murine RBL5/C transfectant lines expressing HBcAg were established. Intramuscular DNA immunization with plasmid pCMV-1/c (encoding intracellularly expressed core Ag) or pCMV-1/e (encoding secreted precore Ag) efficiently primed specific serum Ab responses and CTL responses. The CTL response elicited in this system was mediated by CD4-CD8+ effector cells primed in vivo. The CTL recognized the HBcAg93-100 8-mer peptide MGLKFRQL in the context of Kb. Hence, DNA immunization with HBcAg/HBeAg-expressing plasmids, but not immunization with exogenous HBcAg particles, elicits a class I-restricted CTL response of defined epitope/restriction specificity in H-2b mice.
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PMID:DNA immunization induces antibody and cytotoxic T cell responses to hepatitis B core antigen in H-2b mice. 862 3

We have shown that antisense oligonucleotides can be targeted to hepatitis B virus (HBV)-infected cells, resulting in specific inhibition of viral protein synthesis and replication in vitro. The targeting system was based on the internalization of DNA complexes by highly selective receptors for galactose-terminal glycoproteins, asialoglycoproteins, on the surface of hepatocytes. Our objective in this study was to determine whether antisense DNA could be targeted to hepatocytes to prevent subsequent infection by HBV. A 21-mer phosphorothioate-linked oligo DNA complementary to the HBV polyadenylation signal and 5'-upstream sequences was complexed to a targetable DNA carrier consisting of asialoglycoprotein coupled to polylysine. Pretreatment of Huh7, asialoglycoprotein receptor (+) cells, with antisense complexes before lipofection with an HBV-plasmid at a level of 6.5 x 10(6) copies of plasmid per cell inhibited the amount of newly synthesized, core-associated viral DNA in Huh7 cells to undetectable levels, less than 0.1 pg, as assessed by quantitative polymerase chain reaction (PCR). Hepatitis B viral RNA transcripts were decreased by 60% compared with controls as detected by RNase protection assays, and HBV surface antigen (HBsAg) accumulation was inhibited by 97%. The inhibition lasted for 6 days and was dose dependent. Controls consisting of antisense alone and a random oligo complex showed no significant effect on any of the parameters under identical conditions. We conclude that preexposure of cells to targeted complexed antisense DNA can substantially block viral gene expression and viral replication after transfection of HBV DNA.
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PMID:Inhibition of hepatitis B virus replication by targeted pretreatment of complexed antisense DNA in vitro. 867 42


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