Two plasmids containing a single copy of hepatitis B virus (HBV) genome (ayw or adw) have been introduced into mouse Ltk-cells by calcium precepitation and cotransformation with cloned herpes simplex virus thymidine kinase (tk) gene.

• 用共转化技术分别将两种亚型的单拷贝HBV-DNA重组质粒与HSV-tk基因一起导入Ltk细胞获得成功。