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)

Hepatitis B surface antigens (HBsAg) of both the adw and ayw subtypes have been purified from four different sources. These antigens have been compared by comparison of the products of tryptic hydrolysis performed under conditions which do not disrupt the overall particle morphology of HBsAg. The resultant peptides were compared by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and high performance liquid chromatography followed by amino acid analysis and Edman degradation of the isolated peptides. The same techniques were also applied to HBsAg which had been labeled with tritium in the carbohydrate moiety of the glycoprotein gp-30. These studies demonstrate that residues 122-150 of the protein p-25 and glycoprotein gp-30 occupy an exposed region of the HBsAg lipoprotein particle and contain the major attachment site for carbohydrate in the case of gp-30. The two subtypes were found to differ at two specific positions in this region, suggesting that this is an antigenically important area of the protein.
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PMID:Structure of hepatitis B surface antigen. Correlation of subtype with amino acid sequence and location of the carbohydrate moiety. 710 12

Hepatitis B surface antigen has been purified and its major protein (p-25) and glycoprotein (gp-30) isolated. These isolated proteins have been subjected to amino acid analysis, Edman degradation (30 steps), carboxypeptidase digestion, and peptide mapping following tryptic hydrolysis by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, two-dimensional thin layer chromatography and electrophoresis, and high performance liquid chromatography. These studies demonstrated that p-25 and gp-30 have identical protein structure, differing only by the presence of carbohydrate in gp-30. Removal of this carbohydrate by treatment with anhydrous hydrofluoric acid converted gp-30 into p-25. The NH2-terminal sequence, carboxyl-terminal sequence, and the amino acid composition of several internal tryptic peptides were found to be consistent with the proposed protein sequence based upon the published sequences of hepatitis B viral DNA. The carbohydrate of gp-30 was demonstrated to be attached within the carboxyl-terminal 104 amino acids, most likely between residues 121 and 170.
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PMID:Isolation and characterization of the major protein and glycoprotein of hepatitis B surface antigen. 724 Feb 57

Adult male guinea pigs were immunized with hepatitis B virus polypeptides prepared by Triton X-100 solubilization of purified 22-nm hepatitis B surface antigen (HBsAg) particles. A virus-specific subunit containing both the 28,000 molecular weight glycoprotein and the 23,000 molecular weight protein stimulated both cell-mediated and humoral immunity. A whole-blood-cell transformation assay additionally showed that the 64,000 molecular weight component of HBsAg, previously shown to contain host-specific antigens, also stimulated a cellular response to purified intact HBsAg particles, suggesting the additional presence of virus-specific material in this fraction. Immunization of animals with the 28,000--23,000 molecular weight polypeptides subsequently prepared in micelle form enhanced the demonstration of a cell-mediated reaction after only a single dose of immunogen. The results provide further evidence as to the suitability of HBsAg polypeptides prepared by Triton X-100 solubilization for hepatitis B prophylaxis.
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PMID:Induction of cell-mediated immunity to HBsAg polypeptides. 733 94

Identification of cell surface viral binding proteins is important for understanding viral attachment and internalization. We have fused the pre-S domain of the duck hepatitis B virus (DHBV) large envelope protein to glutathione S-transferase and demonstrated a 170-kDa binding protein (p170) in [35S]methionine-labeled duck hepatocyte lysates. This glycoprotein was found abundantly in all extrahepatic tissues infectible with DHBV and in some noninfectible tissues, though it is not secreted into the blood. The interaction of pre-S fusion protein with p170 was competitively inhibited by wild-type DHBV in a dose-dependent manner. In addition, infection of hepatocytes with DHBV blocked the binding of pre-S fusion protein to p170, which suggests a biological role for p170 during natural infection. The p170 binding site was mapped to a conserved sequence of 16 amino acid residues (positions 87 to 102) by using 24 pre-S deletion mutants; this binding domain coincides with a major virus-neutralizing antibody epitope. Furthermore, site-directed mutagenesis revealed that an arginine residue at position 97 is critical for p170 binding. p170 was purified by a combination of ion-exchange and affinity chromatographies, and four peptide sequences were obtained. Two peptides showed significant similarities to human and animal carboxypeptides H, M, and N. Taken together, these results raise the possibility that the p170 binding protein is important during the replication cycle of DHBV.
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PMID:Interaction between duck hepatitis B virus and a 170-kilodalton cellular protein is mediated through a neutralizing epitope of the pre-S region and occurs during viral infection. 747 30

The potential of the simian immunodeficiency virus (SIV) variable 2 (V2) domain as an effective region to boost SIV-neutralizing antibodies and to protect against live SIV challenge was tested in rhesus macaques. In this study, two rhesus macaques were primed with vaccinia virus recombinants expressing the surface glycoprotein gp140 of SIVmac and were given booster injections with the SIVmac V2 domain presented by a highly immunogenic carrier, the hepatitis B surface antigen (HBsAg). The two vaccinated macaques exhibited SIV-neutralizing antibodies after primer injections that were enhanced by the V2/HBsAg injections. Part of these SIV-neutralizing antibodies were directed specifically to the V2 region, as shown by neutralization-blocking experiments. However, despite having consistent SIV-neutralizing antibody titers, animals were not protected against homologous challenge with BK28, the molecular clone of SIVmac251. No SIV envelope-specific cellular cytotoxic response was detected throughout the immunization protocol, suggesting that neutralizing antibodies directed to SIV envelope gp140 and especially to the V2 domain were unable on their own to protect against SIV challenge. Furthermore, the vaccinees seemed to have higher viral loads than control animals after challenge, raising the question of whether neutralizing antibodies induced by vaccination and directed to the SIV envelope selected viral escape mutants, as shown previously in SIV-infected macaques. This mechanism is certainly worthy of intensive investigation and raises some concern for SIV envelope-targeted immunization.
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PMID:Vaccine-induced neutralizing antibodies directed in part to the simian immunodeficiency virus (SIV) V2 domain were unable to protect rhesus monkeys from SIV experimental challenge. 752 18

Glycoproteins are metabolized through an asialoglycoprotein metabolic pathway in vivo. They are desialylated and taken up by the liver via an asialoglycoprotein receptor. Fibroblast-derived natural human interferon-beta is a glycoprotein having a single asparagine-linked sugar chain. Although natural human interferon-beta may also be metabolized through this pathway, there is very little information about the biologic features of human asialointerferon-beta. We evaluated the pharmacokinetics and biologic activities of human native and asialointerferon-beta s. After intravenous administration to rabbits, human asialointerferon-beta was cleared from the blood circulation faster than the human native interferon-beta. More asialoprotein was distributed to the liver than the native type, but it induced less 2'5'-oligoadenylate synthetase. The human asialointerferon-beta had less activity than the human native interferon-beta on cell growth inhibition and 2'5'-oligoadenylate synthetase induction in Hep-G2 and HuH6 human hepatoblastoma cells. Southern blotting using a hepatitis B virus-transfected HuH6 cell line, HB611, revealed that the inhibition of hepatitis B virus DNA replication by the asialoprotein was weaker than that by the native protein. The results showed that the different effects exerted by the human native and asialointerferon-beta s may be a result of recognition of the sugar chains by rabbit hepatocytes or by human hepatoblastoma cells. The results also suggested that the terminal sialic acid of the sugar chains in natural human interferon-beta significantly affects its pharmacokinetics and biologic activities.
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PMID:Pharmacokinetics and biologic activities of human native and asialointerferon-beta s. 764 42

Hepatitis B virus infection is closely linked to hepatocellular carcinoma (HCC), the pathological mechanism of hepatocarcinogenesis by this virus is not well understood. In order to gain further insight into the molecular mechanism of HCC, we constructed and screened a subtracted c-DNA library which was specific to HCC cells of a woodchuck infected with woodchuck hepatitis B virus. Among eight clones that were isolated based on their differential expressions, we determined nucleotide sequences of two genes whose expressions were most significantly stimulated in HCC. Our results indicate that these two genes appear to be woodchuck counterpart genes of hemopexin (HPX) and alpha-1 acid glycoprotein (AGP), suggesting that the expression of HPX and AGP genes are strongly augmented in tumor cells partly due to transcriptional regulation.
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PMID:Differential gene expression in experimental hepatocellular carcinoma induced by woodchuck hepatitis B virus. 765 24

Duck hepatitis B virus particles bearing the L and S envelope proteins bind a cellular glycoprotein of 180 kDa (gp180) with high affinity and specificity. Binding is mediated by the pre-S region of the L protein and is blocked by neutralizing but not by non-neutralizing monoclonal antibodies to the virus. These and other properties have suggested that gp180 may be a component of the viral entry machinery. Here we report the purification of gp180 from duck liver and the isolation and characterization of cDNA encoding it. DNA sequence analysis of this cDNA indicates that gp180 is a novel member of the basic carboxypeptidase gene family.
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PMID:gp180, a host cell glycoprotein that binds duck hepatitis B virus particles, is encoded by a member of the carboxypeptidase gene family. 779 83

A cannabinoid receptor recombinant baculovirus (AcNPV-THCR) has been constructed and employed to express rat neural cannabinoid receptors. Northern analysis of total RNA from Spodoptera frugiperda (Sf9) insect cells infected with AcNPV-THCR revealed novel hyper-production of a 3.3 kb transcript when probed with nick-translated rat cannabinoid receptor cDNA. Optimal viral protein expression was observed in 35S-metabolically labeled AcNPV-THCR-infected Sf9 cells at a multiplicity of infection of 2.5. Transmission electron microscopy of AcNPV-THCR-infected Sf9 cells showed extensive membrane perturbation and electron-dense cytoplasmic perinuclear accumulation, indicative of receptor glycoprotein expression. Immunofluorescence staining using antiserum produced to a fusion protein consisting of the external domain of the cannabinoid receptor and hepatitis B core antigen revealed cannabinoid receptor expression in AcNPV-THCR-infected Sf9 cells. Scatchard-Rosenthal analysis of [3H]CP55,940 receptor binding indicated a Kd of 3.4 nM and a Bmax equal to 3.17 pmol/mg protein. Western immunoblotting performed on AcNPV-THCR-infected Sf9 cell lysates revealed immunoreactive bands with relative molecular weights ranging from 45 to 79 kDa. The predominant species (55 kDa) exhibited a relative molecular weight consistent with that predicted for the translational product obtained from the cannabinoid receptor cDNA coding sequence. In vitro translation using AcNPV-THCR mRNA also yielded a 55 kDa immunoreactive species. These data indicate that the baculovirus expression system is a viable means of expressing relatively large quantities of cannabinoid receptor recombinant protein.
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PMID:Expression of a cannabinoid receptor in baculovirus-infected insect cells. 794 17

We have previously identified a 180-kDa host cell glycoprotein (gp180) that specifically binds the surface envelope of duck hepatitis B virus (DHBV) and whose binding is inhibited by neutralizing antiviral monoclonal antibodies. Here we map the viral determinants required for gp180 binding to a 66-amino acid region within the preS domain of the envelope coding region. This region includes both major neutralizing preS epitopes previously defined by monoclonal antibodies. Examination of a series of linker-substitution mutations throughout preS indicates that all mutations that block gp180 binding ablate virus infectivity. Interestingly, two mutations that do not prevent binding can also impair infectivity.
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PMID:Analysis of the binding of a host cell surface glycoprotein to the preS protein of duck hepatitis B virus. 803 Feb 12


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