Immune escape by hepatitis B viruses.

摘要: Hepatitis B viruses are DNA characterized by their very small genome size and unique replication via reverse transcription. The circular has been efficiently exploited, thereby limiting variation, leaves no space for genes in addition to those essentially needed during the viral live cycle. prototype non-cytopathic causing persistent infection. Human hepatitis virus (HBV), as well closely related animal viruses, most frequently transmitted vertically from mothers offspring. Because infection usually persists many years, if not lifelong, need efficient mechanisms hide immune response of host. To escape response, they exploit different strategies. Firstly, use structural non-structural proteins multiplely. One purposes is alter response. Secondly, replicate establishing a pool stable extrachromosomal transcription templates, which allow react sensitively changes its microenvironment up- or downregulating gene expression. Thirdly, liver an immunopriviledged site.