Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019158 (hepatitis)
 30,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We used reovirus reassortant genetics and severe combined immunodeficient (SCID) mice to define viral genes important for organ tropism and virulence in the absence of antigen-specific immunity. Adult SCID mice infected with reovirus serotype 1 strain Lang (T1L) died after 20 +/- 6 days, while infection with serotype 3 strain Dearing (T3D) was lethal after 77 +/- 22 days. One hundred forty-five adult SCID mice were infected with T1L, T3D, and 25 different T1L x T3D reassortant reoviruses, and gene segments associated with the increased virulence of T1L were identified. Gene segments S1, L2, M1, and L1 accounted for > 90% of the genetically determined increase in T1L virulence. Gene segment M1 was independently important for virulence, with S1, L2, and L1 alone or in combination also playing a role. T1L grew to higher titers in multiple organs and caused more severe hepatitis than T3D. Seventy adult SCID mice, T1L, T3D, and 15 T1L x T3D reassortant viruses were used to map genetic determinants of viral titers in the brain, intestines, and liver, as well as the severity of hepatitis. Different sets of gene segments were important for determining viral titers in different organs. Gene segments L1 (encoding a core protein) and L2 (encoding the core spike of the virion) were important in all of the organs analyzed. The M1 gene segment (encoding a core protein), but not the S1 gene segment, was a critical determinant of reovirus titer in the liver and severity of hepatitis. The S1 gene segment (encoding the viral cell attachment protein and a nonstructural protein), but not the M1 gene segment, was a critical determinant of titers in intestines and brains. These studies demonstrate that viral growth in different organs is dependent on different subsets of the genes important for virulence. The virion-associated protein products of the four gene segments (L1, L2, M1, and S1) important for virulence and organ tropism in SCID mice likely form a structural unit, the reovirus vertex. Organs (the brain and intestines versus the liver) differ in properties that determine which virulence genes, and thus which parts of this structural unit, are important.
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PMID:Genetic mapping of reovirus virulence and organ tropism in severe combined immunodeficient mice: organ-specific virulence genes. 798 30

As part of the Gambia Hepatitis Intervention Study, hepatitis B antigens and antibodies were assayed in 720 3-4 year old children who had received 4 doses of 10 mcg plasma-derived hepatitis B vaccine in infancy, the findings were compared with 816 controls. The cross sectional study took place from September, 1990, to July, 1991. Study subjects were tested for hepatitis B core antigen (HBcAg), as well as antigens and antibodies to hepatitis surface, e, and core protein, and those testing positive were tested a year later for HBsAg to determine chronic carrier status. Children negative for core antibody and surface antigen were considered uninfected; those positive for core antibody were considered infected; those positive for surface antigen 2 times 6 months apart were considered carriers. 4.6% of the vaccinated children were infected, and 0.6% were chronic carriers. 3 of these carriers had infected or carrier mothers, and 1 had only received 1 dose of vaccine. In the controls, there were 29% judged infected by anti-HBc, including 13% who were also positive for HBsAg. 86% of these were considered chronic carriers when tested a year later. Thus the vaccine was estimated to be 84% effective against infection and 94% effective against chronic carriage. The current Gambian vaccine consists of 2.5 mcg recombinant hepatitis B vaccine.
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PMID:Efficacy of hepatitis B vaccine in the Gambian expanded programme on immunisation. 809 13

Hepatitis B and C viruses (HBV and HCV, respectively) are associated with acute and chronic liver diseases and hepatocellular carcinoma. To elucidate the molecular status of superinfection with these two hepatitis viruses, we cotransfected the full-length or truncated version of HCV structural genes (core and envelope 1) together with the cloned HBV DNA into a human hepatoma cell line (HuH-7). Expression of HBV-specific major transcripts (3.5 and 2.1 kb), as well as HBV antigens (hepatitis B surface antigen and hepatitis B e and core antigens), was reduced about two- to fourfold by the presence of the HCV structural genes. In addition, the secretion of HBV viral particles, including the viral nucleocapsid and mature virion, was drastically suppressed about 20-fold. Analysis of the intracellular HBV core protein-associated nucleic acid indicated that the encapsidated HBV pregenomic RNA was similarly reduced about 14-fold. Deletion analysis of the HCV structural genes demonstrated that the core gene alone or the fragment containing the core protein's N-terminal 122 amino acid residues conferred the same level of suppressive activity as the full-length structural genes. By indirect immunofluorescence, we found that the core protein of HCV was located in the cytoplasm of transfected HuH-7 cells at day 3 posttransfection and was targeted to the nucleus at day 6. Thus, the kinetics of the suppressive effect exerted by HCV constructs matched the timing of core protein entrance into the nucleus. Our results substantiate the clinical finding that HBV markers are suppressed by superinfection with HCV and further imply that this inhibitory effect may occur in the processes of transcription and encapsidation of HBV pregenomic RNA and may be mediated by the core protein of HCV. The deduced amino acid sequence of the HCV core protein has revealed that it is a basic protein which contains a putative DNA-binding motif (SPRG), as well as triplicate nuclear localization signals and several putative protein kinase A and C recognition sites. These characteristics imply that the HCV core protein can also function as a gene-regulatory protein.
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PMID:Suppression of hepatitis B virus expression and replication by hepatitis C virus core protein in HuH-7 cells. 839 58

We previously developed a method for introducing foreign genes into liver tissue using liposomes with incorporated hemagglutinating virus of Japan (HVJ, Sendai virus), and found that liver cells transfected with the E. coli beta-galactosidase gene or the gene for hepatitis B virus (HBV) surface protein (HBsAg) expressed these proteins in vivo. Here, we analyzed cellular reactions leading to hepatitis in the liver by expressing the genes of HBV in vivo. Lymphocytes were eluted directly from liver transfected with the HBsAg genes and shown to be cytotoxic only to cells expressing HBsAg in vitro. These lymphocytes were identified as cytotoxic T lymphocytes with the CD4- CD8+ phenotype. Transfer of these lymphocytes to transgenic mice with the whole HBV genome led to elevation of the serum glutamic-pyruvic transaminase (SGPT) level, indicating the induction of hepatitis due to the cytotoxic T lymphocytes in vivo. Similarly, direct transfer of the gene for the HBV secretory core protein (HBeAg) induced expression of HBeAg in hepatocytes and the appearance of antibody against HBeAg in the serum. However, using this system, we found that the lymphocytes infiltrating the transfected liver showed no cytotoxicity specific for HBeAg. These results indicate that expression of HBsAg, one of the components of virions, in animal liver induced hepatitis efficiently through generation of specific cytotoxic T lymphocytes (CTL) without any expression of the other viral components. This in vivo experimental system should be useful for evaluating how expression of a given gene induces cellular reactions and intrinsic functions in the living body.
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PMID:Use of the hemagglutinating virus of Japan (HVJ)-liposome method for analysis of infiltrating lymphocytes induced by hepatitis B virus gene expression in liver tissue. 839 62

The genomes of two novel members of the Flaviviridae associated with GB agent hepatitis (GB viruses A and B) were cloned and sequenced recently. The genome of a third novel virus (GB virus C), related to but distinct from GB viruses A and B, has also been identified and characterized. Overlapping clones encompassing the large open reading frames of these three viruses have been expressed in E. coli as CTP:CMP-3-deoxy-D-manno-octulosonate cytidylyltransferase (CKS) fusion proteins. Bacterial lysates were subjected to Western blot analyses using sera from GB agent-infected tamarins and human sera from various individuals with or "at risk" for non-A, non-B, non-C, non-D, non-E hepatitis. Antigenic regions were identified in the putative NS3, NS4, and NS5 proteins from all three viruses. An antigenic region was also identified in the putative core protein of GB virus B. Many of the clones identified originally as encoding antigenic proteins were quite large. To map these regions more narrowly, smaller overlapping clones were generated by polymerase chain reaction (PCR), expressed as recombinant CKS fusion proteins and tested by Western blot. Additionally, a lambda gt11 expression library was generated from infectious tamarin sera and immunoscreened. These studies have identified at least three epitopes in GB virus A, five epitopes in GB virus B and four epitopes in GB virus C.
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PMID:Identification of antigenic regions in the GB hepatitis viruses GBV-A, GBV-B, and GBV-C. 869 65

The viral load of hepatitis C virus, as reflected by hepatitis C virus viremia, has been shown to have important clinical implications. In this study the hepatitis C virus core protein level in serum was evaluated for the detection and quantification of hepatitis C virus viremia. Hepatitis C virus core protein in serum was detected using a simple and sensitive fluorescent enzyme immunoassay. Hepatitis C virus core protein was quantitated in 100 healthy subjects, 258 patients with hepatitis C virus infection and 108 patients with non-hepatitis-C-virus-related chronic liver diseases. HCV-RNA was determined using the branched DNA (bDNA) assay and reverse-transcription polymerase chain reaction. The detection limit of this fluorescent enzyme immunoassay was found between 10(4) - 10(5) copies/ml HCV-RNA equivalent. There was a good correlation between the core protein and bDNA assay results (p <0.01). Hepatitis C virus core protein was detected in 81% of patients with hepatitis C virus infection (acute hepatitis 4/5, chronic hepatitis 85/104, cirrhosis 64/73 and hepatocellular carcinoma 56/76) but in none of the healthy subjects and patients with non-hepatitis C virus chronic liver diseases. The amount of hepatitis C virus core protein in patients with hepatitis-C-virus-related hepatocellular carcinoma was lower compared to chronic hepatitis and cirrhosis (p <0.05). All 26 patients treated with interferon-alpha showed parallel changes between HCV-RNA and core protein levels. This fluorescent enzyme immunoassay is simple and quick (assay time <3 h) with sensitivity at least matching the bDNA assay. Similar levels of hepatitis C virus core protein were detected in patients with chronic hepatitis and cirrhosis, but patients with hepatocellular carcinoma tended to have a lower level of hepatitis C virus core protein.
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PMID:Simple fluorescent enzyme immunoassay for detection and quantification of hepatitis C viremia. 875 Jan 76

The capsid particle of hepadnaviruses is assembled from its dimer precursors. However, the mechanism of the protein-protein interaction is still poorly understood. A small region in the capsid protein of woodchuck hepatitis virus (WHV) contains four hydrophobic residues, including leucine 101, leucine 108, valine 115, and phenylalanine 122, that are conserved and spaced every seventh residue in the primary sequence to form a hydrophobic heptad repeat (hhr). A hydrophobic force often plays an important role in the interaction of proteins. Therefore, to investigate the role of this region in capsid assembly, we individually changed the codons specifying these four hydrophobic amino acids to codons specifying alanine or proline. In addition, we examined the in vivo infectivity of a WHV genome bearing a naturally occurring single amino acid change (histidine 104-->proline) in the hhr region. The phenotype of each altered genome was determined in both eukaryotic and prokaryotic systems by a capsid protein assay and electron microscopic examination. We show that replacement of any one of the four hydrophobic residues with alanine did not prevent capsid assembly. However, assembled capsid particles were not detected if combinations of any two of the four residues were substituted with alanines or if the spacing of these four hydrophobic residues was changed. An individual introduction of a proline (which dramatically changes the secondary structure of proteins) into different positions of this small region also abolished capsid assembly in vitro or viral replication in vivo. These results suggested that the hhr region of the core protein of WHV was critical for capsid assembly.
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PMID:A hydrophobic heptad repeat of the core protein of woodchuck hepatitis virus is required for capsid assembly. 879 54

Specific activation of T cells appears to be a prerequisite for viral clearance during hepatitis B virus (HBV) infection. The T-cell response to HBV core protein is essential in determining an acute or chronic outcome of HBV infection, but how this immune response contributes to the course of infection remains unclear. This is due to results obtained from humans, which are restricted to phenomenological observations occurring during the clinical onset after HBV infection. Thus, a useful animal model is needed. Characterization of the T-cell response to the core protein (WHcAg) of woodchuck hepatitis virus (WHV) in woodchucks contributes to the understanding of these mechanisms. Therefore, we investigated the response of woodchuck peripheral blood mononuclear cells (PBMCs) to WHcAg and WHcAg-derived peptides, using our 5-bromo-2'-deoxyuridine assay. We demonstrated WHcAg-specific proliferation of PBMCs and nylon wool-nonadherent cells from acutely WHV-infected woodchucks. Using a cross-reacting anti-human T-cell (CD3) antiserum, we identified nonadherent cells as woodchuck T cells. T-cell epitope mapping with overlapping peptides, covering the entire WHcAg, revealed T-cell responses of acutely WHV-infected woodchucks to peptide1-20, peptide100-119, and peptide112-131. Detailed epitope analysis in the WHcAg region from amino acids 97 to 140 showed that T cells especially recognized peptide97-110. Establishment of polyclonal T-cell lines with WHcAg or peptide97-110 revealed reciprocal stimulation by peptide97-110 or WHcAg, respectively. We vaccinated woodchucks with peptide97-110 or WHcAg to prove the importance of this immunodominant T-cell epitope. All woodchucks immunized with peptide97-110 or WHcAg were protected. Our results show that the cellular immune response to WHcAg or to one T-cell epitope protects woodchucks from WHV infection.
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PMID:Characterization of T-cell response to woodchuck hepatitis virus core protein and protection of woodchucks from infection by immunization with peptides containing a T-cell epitope. 898 24

The distribution and temporal and clinical features of amino acid substitutions of the core protein of hepatitis B (HB) virus were analyzed, using at least 2 sequential samples from 27 patients. Six patients seroconverted from HBe antigen (HBeAg)-positive to anti-HBe-positive (3 went into remission), and 21 were continuously anti-HBe positive with progressive hepatitis. Precore mutations, which terminate HBeAg translation, all appeared by the second sample. Most core mutations occurred between the first and second samples; significantly fewer occurred after the second. In seroconverters who went into remission, mutations occurred in the T helper epitope from aa 50 to 69 (P = .00045); for anti-HBe-positive patients with ongoing disease, mutations occurred in B cell epitopes (P = .0007 for aa 74-83). An ineffective anti-HBc B cell response accounts for ongoing disease and selection of mutations after seroconversion. In those who remit, mutations in the major T helper epitope allow immune escape, thus minimizing immune-mediated hepatitis.
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PMID:Hepatitis B virus core protein mutations are concentrated in B cell epitopes in progressive disease and in T helper cell epitopes during clinical remission. 941 4

Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide, which finally leads to development of hepatocellular carcinoma. Chronic hepatitis C is characterized by several histological features in the liver which discriminate it from other forms of hepatitis: bile duct damage, lymphoid follicles and steatosis (fatty change). Little is known, however, about the role of HCV or its viral proteins in the pathogenesis of hepatitis. Recently, the core protein of HCV has been suggested to have a transcriptional regulatory function, and thereby to be involved in inducing phenotypic changes in hepatocytes. To clarify whether or not the HCV core protein has an effect on pathological phenotypes in the liver, two independent transgenic mouse lines carrying the HCV core gene were established. These mice developed progressive hepatic steatosis, indicating that the HCV core protein plays a direct role in the development of hepatic steatosis, which characterizes hepatitis C. This transgenic mouse system would be a good animal model for the study of pathogenesis in human HCV infection.
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PMID:Hepatitis C virus core protein induces hepatic steatosis in transgenic mice. 922 25


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