title: Superior T cell activation by ESAT-6 as compared with the ESAT-6-CFP-10 complex.
abstract: Using intracellular cytokine staining we show herein that T cells will respond to short-term (6 h) activation with phorbol ester plus ionomycin by production of tumor necrosis factor (TNF), IFN-gamma or both. Here CD4 T cells preferentially produce TNF and CD8 cells IFN-gamma. The same pattern is seen when T cells are activated with the Mycobacterium tuberculosis protein early secretory antigenic target-6 (ESAT-6). Responses with >0.02% IFN-gamma+ CD3 cells were seen in 8 of 10 patients diagnosed with tuberculosis and in 12 of 14 healthy individuals selected for likely exposure to M. tuberculosis. T cell responses to the 1:1 complex of ESAT-6 and culture filtrate protein-10 (CFP-10) were inferior to ESAT-6 alone, and only reached the level of T cell response achieved with CFP-10 alone. Extending the time of incubation to 18 h leads to an increased response to the complex, but it still reached only the level of CFP-10 alone. In vitro digestion with lysosomal enzymes cathepsin L and S at 2000:1 protein to enzyme ratio demonstrates rapid digestion of the individual proteins while the ESAT-6-CFP-10 complex is resistant. The data suggest that the natural complex of ESAT-6-CFP-10 is less amenable to antigen processing leading to a lower T cell response as compared with the individual proteins.
authors.affiliation: Department of Infection, Immunity and Inflammation, Medical Sciences Building, University of Leicester, Leicester LE1 9HN, UK.
authors.forename: Ayman
authors.initials: A
authors.lastname: Marei
authors.forename: Amir
authors.initials: A
authors.lastname: Ghaemmaghami
authors.forename: Philip
authors.initials: P
authors.lastname: Renshaw
authors.forename: Martin
authors.initials: M
authors.lastname: Wiselka
authors.forename: Michael
authors.initials: M
authors.lastname: Barer
authors.forename: Mark
authors.initials: M
authors.lastname: Carr
authors.forename: Loems
authors.initials: L
authors.lastname: Ziegler-Heitbrock
mesh_terms: D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000276:immunology / Q000494:pharmacology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002478:Cells, Cultured; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000276:immunology; D046912:Multiprotein Complexes / Q000276:immunology / Q000494:pharmacology*; D014376:Tuberculosis / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D046912:Multiprotein Complexes