The structure of hepatitis B envelope and molecular variants of hepatitis B virus.

Accumulated evidence in recent years has shown that the variation of hepatitis B virus (HBV) genomes may have profound implications for our understanding of hepatitis B pathogenesis and prevention. Attention has focused on areas of the outer envelope coded by the S gene which are involved in the induction of a protective neutralising antibody response, and mutations which directly affect the production of C gene products, one of which is considered as a target for immune T cells involved in virus clearance. This review highlights recent experimental data which emphasizes the role of such mutations in the establishment and maintenance of chronic HBV infections and focuses attention on the significance of HBV variants with respect to the expanding use of HBV vaccines for mass immunization.