Abstract: Objective The recombinant CFP10-ESAT6 fusion protein coding by the genes located in RD1 regions of genome of Mycobacterium tuberculosis was expressed in E.coli,and its skin reactions were detected inguinea pigs. Methods A genomic DNA of Mycobacterium tuberculosis H37Rv strain was used as template,amplified the cfp10-esat6 fusion gene by Overlap PCR.PCR production was cloned into pET-30a plasmid.The recombinant E.coli was induced by IPTG.The supernatant liquid of centrifugal ultrasonic bacteria was purified through anion column.Skin reactions of fusion protein were tested in guinea pigs infected with M.tuberculosis. Results The fusion proteins was expressed as soluble state in E.coli.The content of recombinant CFP10-ESAT6 fusion proteins was more than 30% of total proteins,and more than 95% purity was acquired through anion column.The fusion proteins could induce DTH in guinea pigs infected with M.tuberculosis and 2.5 μg/ml recombinant proteins induced the same DTH as PPD（50 IU/ml）. Conclusion The recombinant CFP10-ESAT6 fusion proteins is hopeful to become new skin test reagent in the differential diagnosis of tuberculosis.

Key words: Mycobacterium tuberculosis, Recombinant CFP 10-ESAT6 fusion proteins, Guinea pig, Skin reaction