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Updated: Aug 18, 2026
Expression of Exogenous Antigens in the Mycobacterium bovis BCG Vaccine via Non-genetic Surface Decoration with the Avidin-biotin System
Published on: January 31, 2018
[Screening and construction of recombinant BCG strains expressing the Ag85B-ESAT6 fusion protein]
Chang-hong Shi1, Zhi-kai Xu, De-sheng Zhu
1Department of Microbiology, Faculty of Preclinical Medicine, Fourth Military Medical University, Xi'an 710033, China. changhong@fmmu.edu.cn
Objective:
To screen and construct recombinant BCG strains which express the Ag85B-ESAT6 fusion protein.
Methods:
The heat shock protein 60 (Hsp60) and the alpha-ss signal peptide encoding sequence were amplified by PCR from Mycobacterium tuberculosis H(37)Rv and cloned into E. coli/Mycobacteria shuttle vector-pOLYG. The resulting expression vector was named pDE22, and then ag85b and esat6 genes were cloned into pDE22 at different sites. The resulting recombinant plasmids Ag85B-ESAT6 and ESAT6-Ag85 were electroporated into BCG. Positive clones were screened by hygromycin resistance and confirmed by PCR. Recombinant BCG culture supernatants were collected and analyzed by SDS-PAGE and Western blot.
Results:
Two recombinant BCG strains were obtained, which secreted the 37,000 fusion protein in their culture supernatant, which was confirmed by Western blot with specific immune serum against Ag85B and ESAT6.
Conclusions:
Recombinant BCG strains expressing Ag85B and ESAT6 fusion proteins of Mycobacterium tuberculosis were constructed. They may serve as new vaccine candidates for preventing tuberculosis.
