After verified by enzyme analysis, Bgl II was used to removed S gene fragment containing CMV from pCA14 - S to pcD-NA3. 1 + B7 to construct co - expression vector pcDNA3.1 + S + B7, which was verified by enzyme analysis.

• 双启动子共表达载体peDNA3 .；1+S+B7接种组的小鼠抗体产生水平较PcDNA3