Important Role In Virus Assembly Research Articles

Hepatitis B pre‐S1 and pre‐S2 proteins: Clinical significance and relation to hepatitis B virus DNA

Pre-S proteins may have an important role in virus assembly and virus entry into the host cell. The presence of pre-S proteins in serum has also been thought to correlate with active viral replication. To investigate whether pre-S proteins in serum might have additional diagnostic and/or predictive value for liver sequelae in HBV infection, sera from six different serological groups of patients with HBV markers (total number 363) and different manifestations of liver histology were examined for the presence of pre-S1 and pre-S2 proteins using micro-ELISAs. Pre-S1 and pre-S2 proteins were detected significantly more often in HBV-DNA-positive than in HBV-DNA-negative sera from HBsAg carriers. However, pre-S1 and pre-S2 proteins were also found in HBV-DNA-negative HBsAg carriers irrespective of serum HBeAg/anti-HBe or liver histologic findings. These results suggest that the presence of the pre-S1 and or pre-S2 proteins in serum either does not seem to reflect the presence of active viral replication and active liver disease or pre-S proteins are more readily detectable than HBeAg and HB-DNA as measured by a dot-blot technique. Furthermore, the presence of pre-S proteins in serum is strongly correlated with that of HBsAg.

Nature and display of hepatitis B virus envelope proteins and the humoral immune response

The pattern of display of envelope proteins on HBV indicates that the preS domains have an important role in virus assembly and secretion. Furthermore sites of interaction with the membrane of hepatocytes and of other cells which are susceptible to infection have been identified within the preS1 and preS2 protein domains. These observations support the concept that these sequences represent the virus attachment sites for the host cell membrane. The nature of the cellular receptors involved in this binding has not yet been fully clarified. Several B and T cell epitopes, which evoke antibody and cellular response in humans, have been identified within the preS1 and preS2 protein domains. The immune response to some of these determinants seems to be particularly relevant in virus neutralization and in termination of virus replication. Their exact characterization is needed for possible inclusion in recombinant HB vaccines, to further increase their efficacy. The immune response to preS may also be involved in the pathogenesis of liver disease, as preS1 and preS2 epitopes are recognized by cytotoxic T lymphocytes during chronic infection and after HB vaccination. These findings need to be extended further and may provide new important information on the pathogenesis of HBV infection.