ESAT-6

ESAT-6, the 6 kDa early secretory antigenic target produced by "Mycobacterium tuberculosis", is a secretory protein and potent T cell antigen. It is used in tuberculosis diagnosis by the whole blood interferon γ test QuantiFERON-TB Gold, in conjunction with CFP-10 and TB7.7.
ESAT-6 has been shown to directly bind to the TLR2 receptor, inhibiting downstream signal transduction.