目的　构建能表达乙型肝炎病毒 (HBV)S基因的DNA疫苗 ,并在离体与活体条件下评价重组S基因的表达。方法　将克隆的S X基因片段插入真核细胞表达载体 ,获得重组质粒 ,在离体转录系统与转染细胞系中表达重组S基因 ,并在小鼠中评价HBsAg激发抗 HBs的效果。 结果　S基因的表达已通过Northern印迹杂交、Western印迹杂交和ELISA(抗原及抗体检测 )予以证实。结论　S基因已成功地实现体外重组与表达。 Objective To construct DNA vaccine capable of expressing hepatitis B virus S gene and evaluate the expression of recombinant S gene in vitro and in vivo. Methods The cloned S X gene fragment was inserted into the eukaryotic expression vector to obtain the recombinant plasmid. The recombinant S gene was expressed in ex vivo transcription system and transfected cell line, and the effect of HBsAg-induced anti-HBs was evaluated in mice. Results The expression of the S gene has been confirmed by Northern blotting, Western blotting and ELISA (Antigen and Antibody Detection). Conclusion S gene has been successfully recombined and expressed in vitro.