Objective: To construct an eukaryotic expression plasmid containing HBsAg and TB.Hsp70. Methods: By PCR and T-A cloning techniques

the full length gene of TB.Hsp70 from genome of Mycobacterium tuberculosis H37Rv was amplified and cloned directly into pGEM-T vector

then the recombinant plasmid was digested with BamHⅠand EcoRⅠ

and was subcloned into plasmid pcDNA3.1(+) ( pcDNA3.1-HSP70).The HBsAg gene (without stop codon) was amplified from plasmid pEcob6 by PCR . After digested with HindⅢ and BamHⅠ

the PCR product was cloned into plasmid pcDNA3.1-HSP70. Results: Restriction enzyme digesting and DNA sequencing confirmed that the recombinant eukaryotic expression plasmid containing HBsAg and mycobacterium tuberculosis HSP70 (pcDNA3.1-S-HSP70) had been constructed correctly. Conclusion: An eukaryotic expression plasmid pcDNA3.1-S-Hsp70 has been constructed successfully.