Efficient production of hepatitis B surface antigen using a bovine papilloma virus-metallothionein vector

We have developed a highly efficient system for producing hepatitis B virus surface antigen in cultured mammalian cells. This system utilizes a recombinant bovine papilloma virus in which the hepatitis surface antigen coding sequences are inserted into the 5' untranslated region of the mouse metallothionein-I gene. Mouse fibroblasts stably transformed with this molecule produce surface antigen at levels as high as 10 mg/L/24 h and can be maintained in continuous culture for up to 85 days.