The envelope protein of hepatitis B virus (HBV) is referred to as the HBV surface antigen (HBsAg) (8). The antigenic “a” determinant is located from residue 124 to 147 of HBsAg and is involved in eliciting antibody production. Neutralizing antibodies (anti-HBs) target the “a” determinant and generally lead to the disappearance of HBV (1). The coexistence of HBsAg and anti-HBs has been associate...

Background: Genetic changeability of hepatitis B virus (HBV) signifies a challenge for the sensitivity of immunologic and molecular diagnostics. Therefore, knowing the spread of HBV genotypes (GENs) and mutation has considerable impacts on treatment strategies, vaccination program, diagnosis, and prevention. The present study aimed to detect HBV GENs and mutants in HBsAg-positive patients. Meth...

Three clones of hepatitis B virus (HBV) DNA were propagated from sera of each of five patients with chronic hepatitis B who possessed hepatitis B surface antigen (HBsAg) and antibody to HBsAg in their serum. The clones were sequenced within the envelope gene (the preS1, preS2 regions and the S gene). Clones from four patients had various missense mutations involving codons 124-147 of the S-gene...

BACKGROUND It is not known whether hepatitis B virus (HBV) with mutations in the a determinant (amino acids (aa) 121-149) of the hepatitis B surface antigen (HBsAg) affect vaccination efficacy. AIM To investigate the prevalence and clinical significance of these mutants in children, 15 years after universal vaccination in Taiwan. METHODS Nucleotide sequences encoding the a determinant regio...

The presence of hepatitis B virus (HBV) DNA in HBV surface antigen (HBsAg)-negative individuals is defined as occult HBV infection (OBI). OBI is related in some cases to infection with variant viruses (S-escape mutants) undetectable by HBsAg commercial kits. More frequently, however, it is due to infection with wild-type viruses that are strongly suppressed in their replication activity. OBI ma...

HBV is a member of Hepadnavirus genus. HBV is a DNA virus with a diameter of 42 nm consisting of an outer lipid envelope which contains proteins HBsAg, pre-S1 and pre-S2. HBsAg is a product of ‘s’ gen. The s geneinvolves ‘a’ epitope124. -147. codones and this region is the affecting region for anti-HBs antibody binding. Vaccine /Immunglobulin escape mutations occur at HBV DNA s gene’s ‘a determ...

Hepatitis B virus (HBV) infection continues to be a major health problem worldwide. The large-scale immunization programs for persons in high-risk groups, newborns, and adolescents have greatly reduced the incidence of new infection, but the ∼400 million HBV carriers with HBV surface antigen (HBsAg) in the blood remain a burden that will dwindle only within decades. Furthermore, an unknown dise...

Mutations in the core promoter and precore regions of HBV cause down-regulation of HBeAg. These mutations are associated with chronic hepatitis, cirrhosis and Hepato Cellular Carcinoma (HCC). This study was carried out to sequence analysis of HBV core gene in HBsAg- positive blood donors in Iran. A total of 50 HBsAg- positive blood donor samples were examined in this study. Serological markers ...

conclusions the distribution of amino acid mutations as well as the ratio between missense and silent nucleotide mutations (dn/ds) showed that a narrowly focused immune pressure had already been on the surface protein (especially ctl epitopes) which led to the emergence of escape mutants in these patients who were in tolerance phase of chronicity. materials and methods the surface genes from 17...

Impact of hepatitis B virus (HBV) infection on haematopoietic stem cell transplantation (HSCT) was reported earlier since late 1980s. It was shown that changing patterns of HBV serological markers was accompanied by variable severity of hepatitis after transplantation. Recipient's hepatitis B virus surface antigen (HBsAg) positivity was not considered an absolute contra-indication to allogeneic...