Cloning, expression and purification of early secretory antigenic target 6kDa protein (ESAT-6) of Mycobacterium tuberculosis

Introduction and objective: the early secretory antigenic target 6kda protein (esat-6) antigen from mycobacterium tuberculosis is a dominant target for cell-mediated immunity in the early phase of tuberculosis (tb) in tb patients. esat-6 was found to distinguish tb patients from bcg-vaccinated donors. the aim of this study was cloning and expression of esat-6 of m. tuberculosis. materials and methods: dna was extracted from m. tuberculosis h37rv. pcr was performed using gene-specific oligonucleotide primers and the pcr products were inserted into the pet102/d vector and transferred into escherichia coli strain topo10. the recombinant plasmids transferred into e. coli strain bl21. results: the transformed plasmid into e. coli strain bl21 was effectively expressed. the expressed fusion protein (23kda on sds-page) was found almost entirely in the soluble form and the recombinant protein was purified by ni-nta column. conclusion: we successfully cloned and expressed esat-6 protein of m. tuberculosis in e. coli. as a specific antigen, it can be useful for diagnosis of both active and latent tuberculosis with elisa in future.