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...

OBJECTIVE S The aim of this study was to determine the correlation between vaccine therapy and appearance of mutations in hepatitis B surface antigen (HBsAg)-positive chronic hepatitis B virus (HBV) patients. MATERIALS AND METHODS 16 patients received the HBV vaccine and another 16 individuals from the control group did not. The surface gene was amplified and directly sequenced from samples p...

Hepatitis B viral mutants can emerge in patients as a result of selection pressure from either immune response or treatment options. Mutations that occur within the immunodominant epitopes of hepatitis B surface antigen (HBsAg) allow mutant virus to propagate in the presence of a neutralizing immune response, while wild-type virus is reduced to undetectable levels. HBsAg mutants present as fals...

We developed an immunogen to stimulate multivalent immunity against hepatitis B surface antigen (HBsAg) and hepatitis B core antigens (HBcAg). Immune responses specific for both HBsAg and HBcAg play an important role in controlling the infection. HBsAg-specific antibodies mediate elimination of virions at an early stage of infection and prevent the spread of virus. The immunogen was constructed...

hepatitis b vaccination is safe and effective, although breakthrough infection occasionally occurs in those who receive the vaccine and hepatitis b immunoglobulin (hbig) prophylaxis. sequence variation in their antigenic regions is one of the most powerful strategies that are used by viruses to escape recognition by b and t cell-mediated immune responses. the aim of this study was to explore th...

The immunodominant, conformational "a" determinant of hepatitis B surface Ag (HBsAg) elicits Ab responses. We selectively expressed the Ab-binding, glycosylated, native a determinant (residue 120-147) of HBsAg in a fusion protein containing C-terminally the HBsAg fragment SII (residue 80-180) fused to a SV40 T-Ag-derived hsp73-binding 77 aa (T(77)) or non-hsp-binding 60 aa (T(60)) N terminus. A...

To control hepatitis B virus (HBV) infection, a universal HBV vaccination program for infants was launched in Taiwan in 1984. The aim of this study was to investigate the role of B-cell and T-cell epitope variations of HBsAg and polymerase in HBV infection in vaccinated children. One hundred sixty-three sera from vaccinated children were enrolled randomly. HBV serum markers, including hepatitis...

Hepatitis B chronic carriage remains as a major public health problem. Protein and DNA vaccines are now widely used in therapeutic vaccine candidates. Although, the hepatitis B surface antigen (HBsAg) based vaccines have been largely studied, candidates comprising both HBsAg and core (HBcAg) either protein- or DNA-based approaches deserve further immunological characterization. In the present s...

background co-infection with human immunodeficiency virus (hiv) and hepatitis b virus (hbv) is common due to shared routes of transmission, as reported approximately 10% of 33 million hiv-infected patients worldwide are chronically infected with hbv. mutations of hbsag especially within the “a” determinant could alter the antigenicity of the protein, causing failure of hbsag neutralization and ...

In a pilot study, it was established that specific therapy by standard anti-hepatitis B virus (HBV) vaccination may be effective in reducing HBV replication and canceling the immune tolerance to hepatitis B surface antigen (HBsAg) particles in about 50% of persons with chronic active HBV replication. In the present study, the vaccine-induced immune responses were analyzed during an ongoing cont...