A Mycobacterium tuberculosis operon encoding ESAT=6 and a novel low-molecular-mass culture filtrate protein (CFP-10)

Abstract

The early secreted antigenic target 6 kDa protein (ESAT-6) is a potent T-cell protein antigen synthesized by Mycobacterium tuberculosis. Its corresponding gene (esat-6) is located in RD1, a 10 kb DNA region deleted in the attenuated tuberculosis vaccine strain Mycobacterium bowis BCG. The promoter region of M. tuberculosis esat-6 was cloned and characterized. A new gene, designated lhp and cotranscribed with esat-6, was identified. Moreover, computer searches in the M. tuberculosis genome identified 13 genes related to the lhplesat-6 operon, defining a novel gene family. The transcription initiation sites of the lhplesat-6 operon were mapped using M. tuberculosis RNA. The corresponding promoter signals were not recognized in Mycobacterium smegmatis, in which transcription of lhplesat-6 is initiated at different locations. The M. tuberculosis lhp gene product was identified as CFP-10, a lowmolecular-mass protein found in the short-term culture filtrate. These results show that the genes encoding CFP-10 and ESAT-6 are transcribed together in M. tuberculosis and that both code for small exported proteins.

Classically Restricted Human CD8+ T Lymphocytes Derived fromMycobacterium tuberculosis-Infected Cells: Definition of Antigenic Specificity

“…CFP10/Mtb11 is part of an operon that is deleted from BCG. Both members of the operon, CFP10/Mtb11 and ESAT-6, are potent CD4 ϩ T cell Ags in persons infected with Mtb (24,25). Here, we demonstrate that CFP10/Mtb11 is also a potent CD8 ϩ T cell Ag.…”

“…mAbs were generated from hybridoma supernatants from the anti-panHLA (W6/32), anti-HLA-B,C (B1. 23 (24,25), 38 kDa (26), and ESAT-6 (27) proteins were prepared as previously described (18).…”

Top down characterization of secreted proteins from Mycobacterium tuberculosis by electron capture dissociation mass spectrometry

“…ECD, cleaving 35 out of 98 bonds in a single spectrum, showed the removal of the N-terminal Met (131 Da; A 2 -F 100 , Figure 3). CFP-10 was first identified in the short-term culture filtrate by Berthet et al [43], with removal of N-terminus Met shown by Edman sequencing [15]. CFP-10 is co-transcribed with the potent T-cell antigen ESAT-6 for which the function is still unknown.…”

Mycobacterium tuberculosisAntigens Induce the Differentiation of Dendritic Cells from Bone Marrow

“…These Ags were chosen primarily on their demonstrated ability in potentiating immune responses to M. tb. Although both MTSA and ESAT-6 are cotranscribed from the RD1 region of the Mycobacterium genome, they are translated as two separate proteins (31). ESAT-6 has been designated as an important T cell Ag recognized by protective T cells in animal models of infection with M. tb (32).…”