<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

Hepatitis B Core Antigens ; immunology ; Hepatitis B virus ; genetics ; immunology ; Hepatitis B, Chronic ; virology ; Humans ; T-Lymphocytes, Cytotoxic ; immunology

<b>OBJECTIVEb>To evaluate the replication and encapsidation of HBV mutants with the truncated C gene.

<b>METHODSb>The HBV mutants with the truncated C gene were constructed by molecular cloning and PCR-based deletion in vitro. The replication and encapsidation of HBV mutants were investigated by Southern blotting, PCR and real-time fluorescence PCR respectively after transfecting the HBV mutants plasmid into HepG2 cells by using liposome.

<b>RESULTSb>The C-truncated HBV mutant vectors were constructed successfully and confirmed exactly by clone sequencing and enzymes digestion. The C-truncated HBV mutants were replication defective, however, all types of HBV DNA could be detected positive in the cytoplasm and supernatant after co-transfecting the C-truncated HBV mutants plasmid and the helper constructs into HepG2 cells. The C-truncated HBV mutants were proved to produce 3-40 folds more progeny DNA than that of the wild-type HBV by DNA quantitative assay.

<b>CONCLUSIONb>The C-truncated HBV mutants are replication-deficient and could not replicate and encapsulate in the hepatocytes when transfected solely, however, the progeny HBV-variant viruses are encapsidated more effectively to secrete into supernatant when co-transfected with the helper construct which lacks part of 5 prime-proximal HBV RNA packaging signal Epsilon.

Cell Line, Tumor ; Hepatitis B Core Antigens ; genetics ; Hepatitis B virus ; genetics ; physiology ; Humans ; Mutation ; Plasmids ; genetics ; Transfection ; Virus Replication

Genetic Variation ; Hepatitis B Core Antigens ; genetics ; Hepatitis B e Antigens ; genetics ; Hepatitis B virus ; genetics ; immunology ; Humans ; T-Lymphocytes, Cytotoxic ; immunology

<b>OBJECTIVEb>To construct the virus-like parcel expressing hepatitis B virus (HBV) C gene and identify its immunogenicity.

<b>METHODSb>HBV C gene was cloned into the shuttle vector pSC11, and the resulted plasmid pSC11-C was transfected into modified vaccinia virus Ankara (MVA).

<b>RESULTSb>pSC11-C was correctly constructed as verified by sequence analysis and PCR, and the recombinant virus-like parcel possessed good immunogenicity.

<b>CONCLUSIONb>The MVA-C expressing HBV C gene has been successfully constructed to provide important basis for gene therapy research of chronic HBV infection.

Genes, Viral ; Genetic Vectors ; Hepatitis B Core Antigens ; genetics ; Recombination, Genetic ; Vaccinia virus ; genetics

Epitopes, T-Lymphocyte ; HLA-A2 Antigen ; immunology ; Hepatitis B Core Antigens ; genetics ; Hepatitis B virus ; genetics ; immunology ; Humans ; Mutation

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

<b>OBJECTIVEb>To investigate whether the hepatitis B virus (HBV) has quasispecies character by studying nucleotide sequence polymorphism and mutation features of HBV PreC/C gene region, and preliminaryly explore the heterogeneity of HBV quasispecies.

<b>METHODSb>The serum sample was obtained from a patient with chronic hepatitis B, and the whole HBV PreC/C gene region was amplified by PCR and cloned. Thirty-four clones that contained HBV PreC/C gene fragments were sequenced.

<b>RESULTSb>There were 28 kinds of different nucleotide sequences in 34 clones, and the nucleotide sequences diversity ranged from 0.2% to 2.1%. The mutation points were almost distributed in the whole region, but there wasn't mutation at PreC region nt.1 896 point in all sequences.

<b>CONCLUSIONb>Hepatitis B virus has complex quasispecies character in the patients with chronic hepatitis B.

Adult ; Hepatitis B Core Antigens ; genetics ; immunology ; Hepatitis B virus ; classification ; genetics ; isolation & purification ; Hepatitis B, Chronic ; virology ; Humans ; Male ; Mutation ; Promoter Regions, Genetic ; genetics ; Sequence Analysis, DNA

Adolescent ; Adult ; Aged ; DNA, Viral ; Female ; Hepatitis B Core Antigens ; genetics ; Hepatitis B virus ; genetics ; Hepatitis B, Chronic ; genetics ; Humans ; Male ; Middle Aged ; Mutation ; Young Adult

<b>OBJECTIVESb>To investigate the quasispecies dynamics of hepatitis B virus (HBV) during the course of exacerbation and resolution of chronic hepatitis B in a patients.

<b>METHODSb>Five serum samples were collected from a patient with two episodes of exacerbation and resolution of chronic hepatitis B. A method of PCR-TA cloning-conformation sensitive gel electrophoresis (CSGE)-sequencing was performed to study the dynamic changes of HBV quasispecies in basal core promoter (BCP), precore and core regions of HBV genome.

<b>RESULTSb>Quasispecies complexity was 10 and 12 at the points of exacerbations, and 14 and 17 at the points of resolutions (t = 3.133, P < 0.05). Ratio of dominant quasispecies in HBV population was high (42.4% and 51.5%) during exacerbations and low (30.3% and 21.2%) during resolutions (t = 3.295, P < 0.05). All dominant quasispecies, except the one during the second resolution, carried core P5T, L60V, S155T, and precore G1896A mutations.

<b>CONCLUSIONb>The composition of HBV quasispecies changes due to the change of host immune status, and immune pressure might lead to the selection of immune escape mutants.

Adolescent ; Hepatitis B Core Antigens ; genetics ; Hepatitis B virus ; classification ; genetics ; Hepatitis B, Chronic ; immunology ; virology ; Humans ; Male ; Mutation ; Promoter Regions, Genetic ; genetics