Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the last few years it has become possible in the liver to isolate lymphocytes from inflammatory infiltrates and to culture them in vitro. Most of the lymphocyte clones obtained are CD 8+ cytotoxic cells, but interactions between these lymphocytes and hepatocytes in primary culture have not been analysed previously. In this study, cloned human T lymphocytes from liver biopsies and from the peripheral blood of patients with chronic hepatitis B or primary biliary cirrhosis, after phenotypical and functional characterization into CD 8+ or CD 4+ cytotoxic lymphocytes, were activated in an antigen-independent fashion by adding either anti CD 3 or anti CD 2/R-3 monoclonal antibodies to the cell suspension. The activated cells were then coincubated with rat hepatocytes in primary culture. The killing capacity of the activated lymphocytes was monitored by light and electron microscopy and by measurement of lactic dehydrogenase (LDH)-release into the culture medium. It was found that cytotoxic CD 8+, but not CD 4+ helper lymphocytes very effectively killed hepatocytes. The killing effect was dependent on the time of cocultivation and on effector-target (E/T) ratio. Total breakdown of the hepatocyte monolayer was achieved after 10-20 h coculture and at an E/T ratio of 10 to 1. As LDH-release in the culture medium reached about 80% of the total LDH-content, most of the hepatocytes were lysed by activated lymphocytes. Cytotoxic activity of clones obtained from different biopsies was comparable with that of clones from peripheral blood. Hepatocytes in primary culture seem to be very sensitive to the killing capacity of activated cytotoxic lymphocytes.
Virchows Arch B Cell Pathol Incl Mol Pathol 1990
PMID:Lymphocytes from hepatic inflammatory infiltrate kill rat hepatocytes in primary culture. Comparison with peripheral blood lymphocytes. 198 May 56

Hepatitis B viral particles (HB-VP) were purified from sera of chronic hepatitis B surface antigen (HBsAg) positive carriers by consecutive isopycnic and rate-zonal sedimentation in sucrose gradients. Their immunological properties [HBsAg, hepatitis B core antigen (HBcAg) and hepatitis B e-antigen (HBeAg) activities] were examined by a radioimmunoassay based upon the classical "sandwich principle". A double antibody specificity radioimmunoassay (DAS-RIA) was then developed to determine whether envelope proteins (HBsAg) with binding activity for polymerized human serum albumin (pHSA-BA) were associated with core-specific antigenicities (HBc/HBeAg). An e-antigen activity cosedimenting with intact HB-VP (negative for HBcAg reactivity) was detected in association with HBsAg and receptors for pHSA. The presence of HBcAg-specific determinant(s) on HBeAg molecules was also indicated by DAS-RIA. So, we postulated that such hepatitis B virion (HBV) specific molecules are involved in immune complexes with anti-HBc as antibodies in sera of patients with chronic HBV infection. To define the significance of these molecular forms in HB-VP morphogenesis, we studied the effects of a mild treatment with a chaotropic salt, NaSCN, on HB-VP-rich fractions (DNA polymerase positive). A small mol. wt HBeAg derived from HB-VP by dissociating treatment was detected. We found that core-specific determinants (HBe/HBcAg) were bound to large surface proteins (HBsAg) with pHSA-BA and therefore probably contained the pre-S sequence. The selective release from HB-VP of such molecular forms, which could be a product of the major S-region transcript, suggests that they may be components of complete virions.
Mol Immunol 1985 Nov
PMID:Demonstration of a firm association between hepatitis B surface antigen proteins bearing polymerized human albumin binding sites and core-specific determinants in serum hepatitis B viral particles. 241 11

Serum HBV-DNA is considered the best parameter for monitoring HBV replication in the liver. The filter hybridization assay (spot test) with 32P-labelled HBV-DNA has been the technique more frequently used to date. A simple solution hybridization assay, in which 125I HBV-DNA is used as labelled probe, has been recently standardized. We have compared the performances of these two assays for the detection of HBV-DNA. The results were similar with the two methods: an agreement was found in 39/44 (89%) samples. Three sera were positive only by the spot assay-and two only by the liquid phase assay. However, in these cases, HBV-DNA levels were near the sensitivity limits of the assay. Therefore, the filter and the liquid phase assays can be considered to be suitable methods to monitor HBV replication, a fundamental index for the clinical assessment and prognosis of patients with HBsAg positive chronic hepatitis.
Mol Cell Probes 1989 Sep
PMID:Serum HBV-DNA in anti-HBe positive patients detected by filter and liquid phase hybridization assays. 267 82

The pathogenesis of hepatitis B virus (HBV) infection is variable and can result in the development of acute and chronic hepatitis, cirrhosis and primary hepatocellular carcinoma (PHC). In this review, the relationship between the patterns of virus gene expression, host immunological responses, and liver pathology in chronic infection will be discussed. Available evidence suggests that the virus is not directly cytopathic to liver cells and that the pathologic sequelae to infection are mediated by both humoral and cellular immune responses against one or more virus gene products. In addition, chronic liver disease might also be mediated by autoaggressive immune responses that may be stimulated by the direct action of virus gene products upon host gene expression, by the lysis of infected hepatocytes by virus specific host immune responses, or by both. Given the complex and variable outcome of HBV infection, the lack of adequate treatment for chronic liver disease, and the fact that long-term infection dramatically increases the risk of developing PHC, the future provides challenges for devising new models to study, understand and successfully manipulate the pathogenesis of chronic HBV infection.
Mol Biol Med 1989 Oct
PMID:Hepatitis B virus gene products as immunological targets in chronic infection. 269 58

The purpose of this study was to compare the serological analysis for hepatitis C infection using the recombinant immunoblot assay (RIBA) to the direct in situ localization of the hepatitis C viral genome using the reverse transcriptase (RT) in situ PCR technique. Concurrent sera and liver biopsies from 42 patients with clinical and histologic evidence of chronic liver disease were studied. Antibodies against hepatitis C specific antigens were demonstrated by RIBA in the sera of 39/42 (92%), and PCR amplified viral cDNA was detected in the biopsies of 21 (54%) of the 39 seropositive patients. The detection rate using standard in situ hybridization for the tissues known to be viral positive with RT in situ PCR was 9/21 (42%). It is concluded that approximately one-half of patients with chronic hepatitis and serologic evidence of hepatitis C infection will not have virus detectable in their liver biopsy even with a highly sensitive PCR-based technique.
Diagn Mol Pathol 1995 Jun
PMID:Comparison of serologic analysis and in situ localization of PCR-amplified cDNA for the diagnosis of hepatitis C infection. 755

Immunohistochemical methods have been used to localize an HCV antigen on paraffin embedded liver tissue sections by means of monoclonal antibodies to C100-3 nonstructural protein. Peroxidase-antiperoxidase, alkaline phosphatase-antialkaline phosphatase, biotin-streptavidin-peroxidase and immunogold silver staining methods showed a nuclear staining of the hepatocytes in cases of chronic hepatitis with positive HCV serology, alcoholic liver disease and hepatocarcinoma. No cross reactions were observed with viral hepatitis B and delta antigens. The strongest reaction without background staining was obtained with immunogold silver staining. Nuclear localization was compared to the cytoplasmic staining described in the literature.
Cell Mol Biol (Noisy-le-grand) 1993 May
PMID:Nuclear immunostaining of hepatitis C infected hepatocytes with monoclonal antibodies to C100-3 nonstructural protein. Comparison of immunogold silver staining with other immunohistochemical methods. 787 66

Human hepatitis delta virus (HDV) poses a health threat in populations where chronic hepatitis B is endemic. It is a single-stranded RNA virus of 1700 nucleotides and both genomic and antigenomic sequences contain ribozymes which are important for viral replication. Using ribozyme constructs we show that several classes of antibiotics inhibit the self-cleavage reaction of the HDV ribozyme. Antibiotics of the aminoglycoside, peptide and tetracycline classes all inhibit HDV cleavage in vitro at micromolar concentrations. Neomycin (an aminoglycoside) inhibits HDV self-cleavage with a Ki value of 28 (+/- 10) microM. Neomycin inhibition can be reversed by increasing magnesium ion concentration in a competitive manner. Lead acetate cleaves positions G76, A42 and G28, which surround the ribozyme cleavage site. Both Mg2+ and neomycin prevent lead cleavage. Footprinting experiments using base-specific chemical probes revealed enhanced modifications of a set of bases by neomycin, overlapping with the above mentioned lead cleavages. These observations may indicate that neomycin directly displaces divalent metal ions essential for catalysis.
J Mol Biol 1996 Jun 28
PMID:Inhibition of the self-cleavage reaction of the human hepatitis delta virus ribozyme by antibiotics. 868 94

HCV C100-3 non-structural and core proteins have been detected by immunohistochemical methods on paraffin-embedded tissue sections using monoclonal antibodies in 22 cases of chronic hepatitis C. C100-3 protein was detected in cytoplasm and nuclei of hepatocytes whereas core protein was only detected in nuclei. The specificity of the nuclear localization of HCV antigens was discussed in relation to cross-reactivity of the anti core antibody with host-derived GOR antigen.
Cell Mol Biol (Noisy-le-grand) 1996 Jun
PMID:Immunohistochemical detection of hepatitis C virus related C100-3 and core antigens in formalin-fixed liver tissue. 882 11

In living cells reactive oxygen species (ROS) are formed continuously as a consequence of metabolic and other biochemical reactions as well as external factors. Some ROS have important physiological functions. Thus, antioxidant defense systems cannot provide complete protection from noxious effects of ROS. These include oxidative damage to DNA, which experimental studies in animals and in vitro have suggested are an important factor in carcinogenesis. Despite extensive repair oxidatively modified DNA is abundant in human tissues, in particular in tumors, i.e., in terms of 1-200 modified nucleosides per 10(5) intact nucleosides. The damaged nucleosides accumulate with age in both nuclear and mitochondrial DNA. The products of repair of these lesions are excreted into the urine in amounts corresponding to a damage rate of up to 10(4) modifications in each cell every day. The most abundant of these lesions, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), is also the most mutagenic, resulting in GT transversions which are frequently found in tumor relevant genes. A series of other oxidative modifications of base and sugar residues occur frequently in DNA, but they are less well studied and their biological significance less apparent. The biomarkers for study of oxidative DNA damage in humans include urinary excretion of oxidized nucleosides and bases as repair products and modifications in DNA isolated from target tissue or surrogate cells, such as lymphocytes. These biomarkers reflect the rate of damage and the balance between the damage and repair rate, respectively. By means of biomarkers a number of important factors have been studied in humans. Ionizing radiation, a carcinogenic and pure source of ROS, induced both urinary and leukocyte biomarkers of oxidative DNA damage. Tobacco smoking, another carcinogenic source of ROS, increased the oxidative DNA damage rate by 35-50% estimated from the urinary excretion of 8-oxodG, and the level of 8-oxodG in leukocytes by 20-50%. The main endogenous source of ROS, the oxygen consumption, showed a close correlation with the 8-oxodG excretion rate although moderate exercise appeared to have no immediate effect. So far, cross-sectional study of diet composition and intervention studies, including energy restriction and antioxidant supplements, have generally failed to show an influence on the oxidative DNA modification. However, a diet rich of Brussels sprouts reduced the oxidative DNA damage rate, estimated by the urinary excretion of 8-oxodG, and the intake of vitamin C was a determinant for the level of 8-oxodG in sperm DNA. A low-fat diet reduced another marker of oxidative DNA damage in leukocytes. In patients with diseases associated with a mechanistically based increased risk of cancer, including Fanconi anemia, chronic hepatitis, cystic fibrosis, and various autoimmune diseases, the biomarker studies indicate an increased rate of oxidative DNA damage or in some instances deficient repair. Human studies support the experimentally based notion of oxidative DNA damage as an important mutagenic and apparently carcinogenic factor. However, the proof of a causal relationship in humans is still lacking. This could possibly be supported by demonstration of the rate of oxidative DNA damage as an independent risk factor for cancer in a prospective study of biobank material using a nested case control design. In addition, oxidative damage may be important for the aging process, particularly with respect to mitochondrial DNA and the pathogenesis of inflammatory diseases.
J Mol Med (Berl) 1996 Jun
PMID:Cancer risk and oxidative DNA damage in man. 886 11

CD4 T-lymphocytes, which orchestrate immune responses, receive a cognitive signal when clonally distributed receptors are occupied by MHC class II bound peptides on antigen-presenting cells. The latter provide costimulatory or accessory signals through macromolecules such as B7.1 and B7.2 which interact with coreceptors on T-cells to regulate outcomes in terms of T-cell activation or specific non-responsiveness. Complementary studies at the chemical level have implicated Schiff base formation between specialised carbonyls and amines, constitutively expressed on antigen-presenting cell and T-cell surfaces, as an essential element in specific T-cell activation. The small xenobiotic Schiff base forming molecule tucaresol, which substitutes for the physiological donor of carbonyl groups to provide a costimulatory signal to CD4 T-helper lymphocytes (Th-cells), has been developed for testing as an immunopotentiatory drug. Tucaresol, which is orally bioavailable and systemically active, enhances CD4 Th-cell and CD8 cytotoxic T-cell responses in vivo and selectively favours a Th1-type profile of cytokine production. In murine models of virus infection and syngeneic tumour growth it has substantial therapeutic activity. Schiff base formation by tucaresol on T-cell surface amines provides a costimulatory signal to the T-cell through a mechanism that activates clofilium-sensitive K+ and Na+ transport. The signalling pathway utilised by tucaresol converges with T-cell receptor signalling at the level of MAP kinase, promoting the tyrosyl phosphorylation of ERK2 by MEK (mitogen-activated protein kinase kinase). The Schiff base forming class of immunopotentiatory drug provides the first orally active, mechanism-based immunopotentiatory agents for therapeutic testing. Tucaresol is currently undergoing pilot phase I/II clinical trials as an immunopotentiator in chronic hepatitis B virus infection, HIV infection and malignant melanoma.
J Mol Med (Berl) 1996 Sep
PMID:Schiff base forming drugs: mechanisms of immune potentiation and therapeutic potential. 889 54


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