Construction and production of 16 kDa antigen from Mycobacterium tuberculosis for the development of TB diagnotic test

Objective To construct and produce protein of 16 kDa antigen from Mycobacterium tuberculosis by genetic engineering method and evaluate the potential of the antigen to be used in serodiagnosis of tuberculosis (TB) Materials and Methods The plasmid pET21a-hspX was constructed and transformed into Escherichia coli BL21 (DE3) to express protein of 16 kDa antigen. The isolated antigen was then evaluated for its potential to be used in antibody detection by ELISA and Western blot analysis Results The protein 16 kDa antigen was expressed at high level in E. coli in insoluble form (inclusion bodies). The protein could be obtained at high yield and purity after isolation, solubilization and refolding. By Western blot analysis and ELISA, the 16 kDa antigen showed strong reactivity with serum of TB patients including smear positive pulmonary TB, smear negative and extrapulmonary TB. Conclusion The 16 kDa TB antigen was successfully cloned and expressed in this study. This antigen showed high potential to be used for serodiagnosis of TB in further study. Bull Chiang Mai Assoc Med Sci 2008; 41: 204-213.