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)

Mice were immunized against duck hepatitis B virus core (DHBc) particles isolated from the liver of asymptomatic carrier ducks of duck hepatitis B virus (DHBV) by ultracentrifugation. Their spleen cells were fused with mouse myeloma (NS-1) cells, and 12 clones of hybridoma cells secreting antibodies against DHBc (anti-DHBc) were isolated. According to the reactivity to core particles and core peptide obtained from DHBc particles treated with SDS-2ME, the 12 antibodies were classified into two groups. Two monoclonal antibodies reacted against both core particles and core peptide (B-type), the other ten monoclonal antibodies reacted against core particles but did not react against core peptide obtained from DHBc particles treated with SDS-2 ME. (A-type). Solid phase enzyme immuno assay (EIA) using these two types of antibodies could detect core antigenisity not only in the liver homogenate but also in the DHBV infected serum. Sucrose gradient analysis and gel filtration analysis revealed this DHBc antigenisity in the serum is not carried by core particles but carried by core peptide, equivalent to HBe antigen in the serum of Hepatitis B virus (HBV) carrier. This EIA may provide sensitive test monitoring both serum DHBe antigen levels and DHBc antigen levels in the liver during DHBV infection.
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PMID:[Preparation of monoclonal antibodies against duck hepatitis B core antigen and analysis of the monoclonal antibodies]. 269 Apr 59

An attempt was made to develop a safe, efficacious live recombinant vaccine using low neurovirulent strains of vaccinia virus: LC16m0 (m0) or LC16m8 (m8). Recombinant vaccinia virus (RVV) was constructed by inserting the hepatitis B surface antigen (HBsAg) gene fused to a 7.5 kDa protein promoter (7.5 kDa promoter) within the vaccinia virus thymidine kinase (TK) gene using the m0 or m8 strain as vectors. These RVVs expressed significant amounts of HBsAg (1.1 microgram/2 X 10(5) cells) consisting of 24.5 and 28 kDa (glycosylated) proteins. HBsAg produced by RVV (vaccinia HBsAg) had physical properties very similar to plasma-derived HBsAg. Considering the safety of RVVs from m0 or m8 that have been constructed with HBsAg without the addition of a promoter and the high induction of anti-HBs antibody with RVV from m0 strain in rabbits, the RVVs constructed in the present study are likely to form the basis of a safe live RVV vaccine for hepatitis B virus (HBV).
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PMID:Improved recombinant LC16m0 or LC16m8 vaccinia virus successfully expressing hepatitis B surface antigen. 271 7

A fused gene containing 94% of the hepatitis B virus (HBV) open reading frame X was expressed in Escherichia coli, and its 17-kDa product was purified by ion-exchange chromatography. Antibody elicited against the X-gene product reacted with materials proximal to the nuclear membrane of a human hepatoblastoma cell line producing HBV particles. No such reaction was observed with the same cell line that did not produce HBV particles.
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PMID:Purification of hepatitis B virus gene X product synthesized in Escherichia coli and its detection in a human hepatoblastoma cell line producing hepatitis B virus. 283 51

Recently we have shown that the hepatitis B virus (HBV) X gene encodes a transactivating factor. Here we report on the construction of a series of HBx expression plasmids which were tested for a transactivating function by cotransfections with a plasmid expressing the CAT gene under control of the SV40 early promoter. One of the plasmids, expressing a HBx specific protein, is shown to transiently transactivate CAT gene expression after cotransfection into the human cell line CC113. Furthermore, a cloned integrated HBV DNA sequence is also shown to transactivate several viral promoters and LTRs. By sequence analyses we can demonstrate that only the HBx ORF is intact and that it is fused to an ORF of at least 228 bp in the flanking cellular DNA. The HBx gene is cotranscribed with the flanking cellular DNA, resulting in a RNA of approximately 10 kb. By subcloning of the integrate we can demonstrate that the presence of the HBx gene and its expression by the HBV enhancer and/or the HBx promoter is required for the transactivating function of the integrated HBV DNA.
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PMID:A transactivating function encoded in the hepatitis B virus X gene is conserved in the integrated state. 285 54

The hepatitis B virus (HBV) genome carries an open reading frame of 462 bases, the X region, but the corresponding protein has yet to be identified as a natural product. In rodent cells cotransformed with the thymidine kinase gene of herpes simplex virus and HBV DNA, however, Gough [1983] identified a mRNA that hybridises uniquely with the X region of the HBV genome. A large fragment of the X region was inserted into plasmid pCL19 delta Y-T in order to produce, in Escherichia coli, the X gene product, HBxAg, as a polypeptide fused to the N-terminal part of the phage lambda cro gene product. Antisera raised against this fused polypeptide gave positive immunofluorescence reactions with the transformed rodent cells. This provides direct evidence for the expression of the HBxAg gene in eukaryotic cells transformed with HBV DNA. The approach used here should be generally applicable.
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PMID:Expression of the X gene of hepatitis B virus. 294 12

Region X is one of the four open reading frames (ORFs) of hepatitis B virus (HBV) and encodes a polypeptide of 154 amino acids (aa). A 584-bp BamHI-BglII fragment of the HBV DNA containing the major part of ORF X which encodes 145 aa was inserted into the BglII site within the gene II of bacteriophage M13. The insertion resulted in an in-phase gene II-X fused protein of 174 aa under the control of the gene II promoter. Cells harboring plasmids (pML alpha X.59 and pMLX.12d) derived from the above construct overproduced the 19-kDa fused protein in Escherichia coli at a level of 10%-20% of total cellular protein. The fused protein was recognized by the anti-X antibodies. This is the first demonstration of using gene II promoter of M13 to express a foreign gene efficiently.
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PMID:High-level production of hepatitis B viral X protein in Escherichia coli using gene II promoter of bacteriophage M13. 296 57

The hepatitis B surface antigen (HBsAg) is highly immunogenic and induces an antibody response which is protective in vivo against hepatitis B virus (HBV) infection. Human monoclonal antibodies specific for HBsAg were produced, which could have potential therapeutic applications. Lymphocytes obtained from a vaccinated donor were stimulated in vitro and fused with the human myeloma cell line GM 4672, and eight hybridomas were obtained. Three of these clones, which reacted in an ELISA against the HBsAg vaccine, were expanded, subcloned and further analyzed. The subclones E7C2, C4C10, and D5B2 were able to bind to different HBsAg preparations, which express various subtypes, and recognized the major HBsAg peptides in Western blot analysis. Cross-inhibition experiments showed that E7C2, C4C10 and D5B2 are directed against the same epitope and have an affinity constant ranging from 5 X 10(7) to 3.3 X 10(9) M. Furthermore, these antibodies stained the surface and cytoplasm of the HBsAg-secreting cell lines PLC/PRF/5 and 4.10. The production of immunoglobulins varies from 0.3 to 1.3 micrograms/ml/10(6) and has remained stable over a period of 8 months. These human monoclonal antibodies, which appear to be directed against an antigenic determinant common to all HBsAg subtypes, could be useful in the study of HBV-related liver diseases as well as in their diagnosis and experimental therapy.
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PMID:Preparation and characterization of human monoclonal antibodies directed against the hepatitis B virus surface antigen. 348 52

A method of introducing actively expressed genes into intact mammals is described. DNA precipitated with calcium phosphate has been injected intraperitoneally into newborn rats. The injected genes have been taken up and expressed by the animal tissues. To examine the generality of the method we have injected newborn rats with the chloramphenicol acetyltransferase prokaryotic gene fused with various viral and cellular gene promoters and the gene for hepatitis B surface antigen, and we observed appearance of chloramphenicol acetyltransferase activity and hepatitis B surface antigen in liver and spleen. In addition, administration of genes coding for hormones (insulin or growth hormone) resulted in their expression.
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PMID:Direct introduction of genes into rats and expression of the genes. 354 Sep 43

As a model system for the study of factors affecting gene expression, hepatitis B virus core antigen (HBcAg) has been expressed in the yeast Saccharomyces cerevisiae. The singularly high levels of expression achieved are approx. 40% of the soluble yeast protein. The HBcAg polypeptides are present as 28-nm particles which are morphologically indistinguishable from HBcAg particles in human plasma and are highly immunogenic in mice. The plasmid construction employed to achieve these very high levels of expression utilizes the constitutively active yeast promoter from the GAP491 gene which is fused in a way that all non-translated sequences flanking the HBcAg coding region are yeast-derived. Hybrid constructions containing 3'-nontranslated viral DNA (yeast 5') or 5'-nontranslated viral DNA (yeast 3') as well as a construction with both 5'- and 3'-nontranslated viral DNA also have been made. A comparison of these constructions for levels of HBcAg expression indicates that the strongest contributor to the high levels of protein is the presence of 5'-flanking sequences which are yeast-derived; secondarily, a significant improvement can be achieved if the 3'-flanking sequences also are yeast-derived. The high abundance of HBcAg in the highest producer is explicable in part on the basis of the very high stability in yeast cells of HBcAg polypeptides. Analysis of the HBcAg coding sequence reveals a very low index of codon bias for S. cerevisiae, largely discounting codon usage as a contributor to the high level of protein obtained.
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PMID:Unusually high-level expression of a foreign gene (hepatitis B virus core antigen) in Saccharomyces cerevisiae. 354 16

The yeast vector pPV2 has been constructed for inducible expression of non-fused proteins from the PHO5 promoter. Signals of the URA3 gene are used for transcription termination. The 226-amino-acid 'major' and the 389-amino-acid 'large' envelope protein of hepatitis B virus (HBV) have been produced in Saccharomyces cerevisiae following insertion of the S gene or of the entire pre-S region and the S gene, respectively, of HBV into pPV2. Although normally only a minor constituent of the viral envelope, the 'large' protein forms particles with cellular lipids similar to those composed of the 'major' envelope protein. Such particles carry pre-S1, pre-S2, and S-encoded epitopes and, in addition, a receptor for polymerized human serum albumin.
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PMID:Expression of the hepatitis B virus large envelope protein in Saccharomyces cerevisiae. 354 60


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