Production of hepatitis B virus surface antigen in normal and immortalized transgenic mouse hepatocytes

Hepatocytes of transgenic mice containing hepatitis B virus DNA were cultured as primary cells or were immortalized with SV 40. Under defined culture conditions, expression of factors specific for mature hepatocytes and HBsAg could maintained for several weeks. After immortalization with SV 40, although the cells kept several of their differentiated functions, production of HBsAg was lost. Analysis of the RNA revealed the presence of a 1-kb species hybridizing specifically to the X gene in addition to the 2.1-kb SmRNA. (ITA)