目的　构建结核分支杆菌分泌蛋白Ag85B编码基因的DNA疫苗。方法　以结核分支杆菌H37Rv基因组为模板 ,PCR扩增Ag85B编码基因 ,用限制性内切酶消化后 ,插入真核表达载体pVax1中 ,转化大肠杆菌DH5α ,进行重组子筛选、鉴定。结果　以结核分支杆菌PCR扩增为阳性 ,经限制性内切酶消化后可见目的条带 ,所测定序列与报道的Ag85B序列一致。 结论　成功地构建了结核分支杆菌Ag85B基因真核表达株。 Objective To construct the DNA vaccine of Mycobacterium tuberculosis secreted protein Ag85B. Methods The Mycobacterium tuberculosis H37Rv genome was used as a template to amplify the Ag85B gene. The gene was inserted into the eukaryotic expression vector pVax1 and transformed into E. coli DH5α. The recombinant plasmid was screened and identified by restriction endonuclease digestion. Results Mycobacterium tuberculosis PCR amplification was positive, the restriction enzyme digestion showed the purpose of the band, the measured sequence consistent with the reported Ag85B sequence. Conclusion The eukaryotic expression strain of Mycobacterium tuberculosis Ag85B gene was successfully constructed.