Amino Acid Sequence ; Hepatitis B Surface Antigens ; classification ; genetics ; immunology ; Hepatitis B virus ; immunology ; Mutation

<b>OBJECTIVEb>To determine the main genotype of hepatitis B virus (HBV) detected from Tibetans in China and provide basic data for hepatitis control and prevention.

<b>METHODSb>The S gene and C gene were amplified by PCR from the sera of HBsAg positive Tibetans. After sequencing, the gene sequences were analyzed and the phylogenetic trees were drawn by the software MEGA3.

<b>RESULTSb>In trees based on S gene, the sequences of most samples clustered at genotype D, while in trees based on C gene, the sequences of all samples clustered at genotype C.

<b>CONCLUSIONb>The dominant genotype of HBV detected from Tibetans in China is a C/D hybrid.

Genotype ; Hepatitis B ; blood ; epidemiology ; virology ; Hepatitis B Core Antigens ; genetics ; Hepatitis B Surface Antigens ; blood ; genetics ; Hepatitis B virus ; classification ; genetics ; immunology ; Humans ; Phylogeny ; Tibet ; epidemiology

<b>OBJECTIVEb>To investigate whether the presence of HBV mutant in vaccinees simply reflects the prevalence of HBV mutant in a specific geographic area or is indeed due to the immune pressure induced by vaccination.

<b>METHODSb>HBV S genes were amplified by using polymerase chain reaction (PCR) and DNA sequence analysis of the "a" determinant was performed on sera from 30 childhood patients with immunoprophylaxis and 30 patients without vaccinations.

<b>RESULTSb>Mutations of the "a" determinant were detected in 8 of the 60 patients. They were all of the adw subtype. The prevalence of amino acid substitutions as detected by direct sequencing was higher in those fully-vaccinated than of those not vaccinated. In all 8 vaccinated and also with detectable mutants, the mean age was older than the other vaccinated children.

<b>CONCLUSIONb>The prevalence of mutants is related to HBV subtypes and genotypes. Universal vaccination has accelerated an accumulation of HBsAg "a" determinant mutants with amino acid changes critical for immune escape in vaccinated children who became carriers. This suggests that new vaccination strategies should be considered.

Child ; China ; Epitopes ; genetics ; Female ; Hepatitis B ; prevention & control ; Hepatitis B Surface Antigens ; genetics ; Hepatitis B Vaccines ; immunology ; Hepatitis B virus ; genetics ; Humans ; Male ; Point Mutation ; Vaccination

Animals ; Hepatitis B Surface Antigens ; blood ; genetics ; immunology ; Hepatitis B Vaccines ; immunology ; Hepatitis B, Chronic ; virology ; Humans ; Protein Precursors ; blood ; genetics ; immunology

<b>OBJECTIVESb>To screen proteins in hepatocytes interacting with hepatitis B virus surface antigen middle protein (MHBs) with yeast-two hybrid technique for studying the biological functions of MHBs.

<b>METHODSb>Polymerase chain reaction (PCR) was used to amplify the gene of MHBs from the plasmid A7 containing the whole fragment of adr subtype of HBV and the PCR product was cloned into pGEM-T vector and then evaluated by sequencing. The gene of MHBs was cut by EcoRI and BamH I from pGEM-T vector and then cloned into the yeast expression plasmid pGBKT7. MHBs bait plasmid was constructed by ligating MHBs gene with yeast expression vector pGBKT7 with yeast-two hybrid system 3 and then was transformed into yeast AH109 (a type). The transformed yeast cells were mated with yeast Y187 (alpha type) containing liver cDNA library plasmid in 2 x YPDA medium. Diploid yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) and synthetic dropout nutrient medium (SD/-Trp-Leu-His-Ade) containing X- alpha -gal for selecting and screening. After extracting and sequencing the plasmid from true positive blue colonies, the results were analyzed by bioinformatics.

<b>RESULTSb>A pGBKT7- MHBs yeast expressed vector was successfully constructed. Two colonies were sequenced. One colony was Homo sapiens aldolase B fructose-bisphosphate, the other was a new gene with unknown function, which was named MHBs-binding protein 1.

<b>CONCLUSIONb>MHBs gene was successfully cloned. Two genes of MHBs interacting proteins in hepatocytes were obtained by yeast-two hybrid system 3. Our results brought some new clues for studying the biological functions of MHBs and the mechanisms of HBV carcinogenesis.

Genome, Viral ; Hepatitis B Surface Antigens ; genetics ; Hepatitis B virus ; genetics ; immunology ; Hepatocytes ; Humans ; Two-Hybrid System Techniques

<b>OBJECTIVEb>To investigate the presentation of a neutralization epitope-containing peptide antigen of hepatitis E virus (HEV) on chimeric virus-like particles (VLPs) of hepatitis B surface antigen (HBsAg).

<b>METHODSb>The gene fragment corresponding to amino acids (aa) 551-607 (HEnAg) of HEV capsid protein, which contains the only neutralization epitope identified to date, was fused via a synthetic glycine linker in frame with the gene of HBsAg. The resulted fusion gene was then integrated through transformation into the genome of Pichia pastoris under the control of a methanol-induced alcohol oxidase 1 (AOX1) promoter and expressed intracellularly. The expression products in the soluble cell extracts were characterized by Western blot, ELISA, CsCl density gradient analysis, and electron microscopic visualization.

<b>RESULTSb>The novel fusion protein incorporating HBsAg and the neutralization epitope-containing HEnAg was expressed successfully in Pichia pastoris with an expected molecular weight of approximately 32 kD. It was found to possess the ability to assemble into chimeric HBV/HEV VLPs with immunological physical and morphological characteristics akin to HBsAg particles. Not only did the chimeric VLPs show high activity levels in a HBsAg particle-specific ELISA but they were also strongly immunoreactive with hepatitis E (HE) positive human serum in a HEV specific ELISA, indicating that HEnAg peptide fragments were exposed on VLP surfaces and would be expected to be readily accessible by cells and molecules of the immune system. Similarity between chimeric VLPs to highly immunogenic HBsAg particles may confer good immunogenicity on surface-displayed HEnAg.

<b>CONCLUSIONb>The chimeric HBV/HEV VLPs produced in this study may have potential to be a recombinant HBV/HEV bivalent vaccine candidate.

Epitopes ; Genetic Engineering ; Hepatitis Antigens ; biosynthesis ; genetics ; immunology ; Hepatitis B Surface Antigens ; biosynthesis ; genetics ; immunology ; Hepatitis B virus ; genetics ; immunology ; Hepatitis E virus ; genetics ; immunology ; Pichia ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; isolation & purification ; Vaccines, Synthetic

Alanine Transaminase ; blood ; DNA, Viral ; blood ; Hepatitis B Antibodies ; blood ; Hepatitis B Core Antigens ; blood ; Hepatitis B Surface Antigens ; blood ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; genetics ; immunology ; Hepatitis B, Chronic ; virology ; Humans

DNA, Viral ; blood ; Female ; Hepatitis B ; immunology ; virology ; Hepatitis B Antibodies ; blood ; Hepatitis B Core Antigens ; immunology ; Hepatitis B Surface Antigens ; immunology ; Hepatitis B virus ; genetics ; isolation & purification ; Humans ; Male ; Polymerase Chain Reaction ; methods

<b>OBJECTIVEb>To evaluate the immunization effects of HBV core antigen and surface antigen fusion protein.

<b>METHODSb>The DNA fragments encoding HBsAg 100-162 aa; HBcAg 1-78 aa and HBcAg 83-144 aa were PCR-amplified, and then cloned into pcDNA3 plasmid. The chimeric gene was subcloned into the prokaryotic vector, pRSET-B. The E.coli expressed recombinant protein purified. BALB/c mice were immunized with recombinant protein or eukaryotic expression plasmid, humoral response and cellular response were examined.

<b>RESULTSb>The plasmid containing the chimeric gene of HBsAg and HBcAg induced effective anti-HBs antibody response and strong HBcAg specific lymphocyte proliferative response, but could not induce anti-HBc antibody response. Fusion protein induced strong anti-HBs and anti-HBc antibody response, and it also caused significant HBcAg specific lymphocyte proliferation. Compared to the recombinant fusion protein, the plasmid containing the chimeric gene of HBsAg and HBcAg can induce more effective cellular response but weaker humoral response.

<b>CONCLUSIONb>Compared to the recombinant fusion protein, the plasmid containing the chimeric gene of HBsAg and HBcAg is a more effective vaccine.

Animals ; Cell Proliferation ; Hepatitis B ; genetics ; immunology ; prevention & control ; Hepatitis B Antibodies ; blood ; Hepatitis B Core Antigens ; genetics ; immunology ; Hepatitis B Surface Antigens ; genetics ; immunology ; Hepatitis B Vaccines ; genetics ; immunology ; Hepatitis B virus ; genetics ; immunology ; Mice ; Mice, Inbred BALB C ; Plasmids ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; T-Lymphocytes ; immunology ; Viroids ; genetics

<b>BACKGROUNDb>To study the difference between the mutant types and the wild type of HBsAg on the binding efficiency with antibodies in order to find some methods to detect the mutants.

<b>METHODSb>The recombinant wild type of HBsAg and the mutants including 145 R, 133 T, 126 S, 141 E, 126 S+133 T, 126 S+133 T+145 R and 126 S+133 T+141 E were cloned, respectively. Then the expression vector containing the wild or mutant gene was transfected into COS7 cells, and the recombinant proteins were expressed. The proteins were detected with the routine HBsAg kits.

<b>RESULTSb>The binding efficiency with monoclonal antibodies of HBsAg expressed by 126 S was higher than that of the wild type, while the results of 145 R, 141 E, 126 S+133 T+145 R and 126 S+133 T+141 E were lower than that of the wild, and 133 T was similar to the wild. But most of the mutants had the same reactivity with the polyclonal antibody.

<b>CONCLUSIONSb>The effect of mutations on antibody binding differs depending on the amino acid involved and on the location within the "a" loop. So it is necessary to use polyclonal antibody or to find new kits to detect the mutants of HBsAg.

Binding Sites, Antibody ; Epitopes ; Gene Transfer Techniques ; Genetic Vectors ; Hepatitis B Surface Antigens ; genetics ; immunology ; Hepatitis B virus ; genetics ; immunology ; Humans ; Mutation ; Recombinant Proteins ; genetics ; immunology