Mycobacterium tuberculosis ESAT-6–CFP-10 fusion protein (ESAT-6–CFP-10)

The Mycobacterium tuberculosis ESAT-6–CFP-10 fusion protein is a recombinant antigen combining two secreted *M. tuberculosis* proteins, ESAT-6 (6 kDa early secreted antigenic target) and CFP-10 (10 kDa culture filtrate protein). These proteins are encoded within the RD1 genomic region, which is present in virulent *M. tuberculosis* but absent in BCG vaccine strains. The fusion protein is highly immunogenic and crucial for both diagnosis and research on tuberculosis: it stimulates strong IFN-γ responses from T-cells in exposed or infected individuals, making it suitable for skin tests and IFN-γ release assays. Functionally, ESAT-6 and CFP-10 modulate host-pathogen interaction, with the fusion protein shown to inhibit autophagy in host macrophages, promoting intracellular survival of *M. tuberculosis* and contributing to granuloma formation and disease progression[1][2][3][4][7][9][10]. As a protein-based reagent, it can be produced recombinantly and is used both in immunological studies and as a component of diagnostics and vaccine research. It is not a classical drug target, but a key tool in clinical testing for tuberculosis and a model antigen for immune monitoring. Safety studies show it is generally well tolerated when used in humans for diagnostic purposes[6].

Other names

ESAT-6/CFP-10 fusion proteinEarly secreted antigenic target 6 kDa – Culture filtrate protein 10 kDa fusionECST (when used for skin test, as in "ESAT6-CFP10 skin test")Recombinant Mycobacterium tuberculosis fusion protein ESAT6-CFP10

Modulates immune response by inhibiting autophagy in host macrophages, enables Mycobacterium tuberculosis survival[1][4] Promotes granuloma formation and immune cell recruitment at infection site[3][10] Induces IFN-γ release from T cells, used as diagnostic stimulus in immune assays[7][9][10]