Ression of either CD69 or HLA-DR on ab DN T-cells of infected patients is similarly increased in TB patients presenting the non-severe and severe form of the disease. cd DN T-cells from TB patients also display an activated phenotype compared with healthy donors. Thus, overall, the DN T population from TB-infected patients presented a profile compatible with previous antigen exposure (HLA-DR) and recent activation (CD69). Host effector immune Title Loaded From File response against M. tuberculosis is related to the presence of a strong Th1 response and memory, leading to the production of immune mediators that activate parasiteinfected macrophages for parasite destruction. One critical cytokine for host control of M. tuberculosis is 23727046 IFN-c. IFN-c is required for induction of NO synthase type 2 and other effector molecules in infected macrophages. Both CD4+ and CD8+ T-cells and NK cells have been shown to be sources of this protective cytokine in M. tuberculosis infection [13,16]. The essential role of IFN-c is evident from the increased risk of tuberculosis in: (i) individuals with deficiency of IFN-c and interleukin-12, which promotes Th1 cell differentiation; (ii) animal models depleted of CD4+ T-cell during the experimental infection; (iii) HIV-infected individuals [25,26]. ab DN T-cells from TB-patients displayed a higher commitment to the production of IFN-c. Moreover they also contained a higher proportion of IFN-c producing cells than the CD4+ and CD8+ ab T-cell population. High frequencies of IFN-c producing cells in TB group are accounted by patients presenting the non-severe form of tuberculosis. A great proportion of ab DN T-cells from nsTB patients are maintain the ability of IFN-c production, which is lost for sTB patients. The reduction of TB-specific T-cells and the impairment of Th1 immune responseRole of CD4-CD8-ab and cd T Cells in TuberculosisFigure 3. Higher frequencies of IFN-c producing DN ab T-cells are found in nsTB patients. Representative contour plots showing the proportions of IFN-c producing CD4 (left panel), CD8 (middle panel) and DN (right panel) ab-T cells (A). The percentages of IFN-c (B), TNF-a (C) and IL10 (D) expression within CD4+ (left panels), CD8+ (middle panels) and DN (right panels) ab T-cells in healthy donors (HD, open MedChemExpress A196 symbols), TB (total TB, black 1317923 symbols), nsTB (non-severe TB, light gray symbols) and sTB patients (severe TB, dark gray) were measured before treatment. PBMCs were stimulated with (MTB-Ag) for 48 hours. The boxes represent the means. doi:10.1371/journal.pone.0050923.gRole of CD4-CD8-ab and cd T Cells in TuberculosisFigure 4. DN cd T-cells from nsTB patients produce inflammatory cytokines whereas those from sTB produce more IL-10. Representative contour plots showing the proportions of IFN-c producing CD4 (left panel), CD8 (middle panel) and DN (right panel) cd-T cells (A). Percentages of IFN-c (B), TNF-a (C) and IL-10 (D) within CD4+ (left panels), CD8+ (middle panels) and DN (right panels) cd T-cells in healthy donors (HD, open symbols), TB (total TB, black symbols), nsTB (non-severe TB, light gray symbols) and sTB patients (severe TB, dark gray) were measured before treatment. PBMCs were stimulated with (MTB-Ag) for 48 hours. The boxes represent the means. doi:10.1371/journal.pone.0050923.gRole of CD4-CD8-ab and cd T Cells in Tuberculosisin active pulmonary tuberculosis patients were reported before [27,28]. cd DN T-cells not only presented higher frequencies of IFN-c producing cells, but they also c.Ression of either CD69 or HLA-DR on ab DN T-cells of infected patients is similarly increased in TB patients presenting the non-severe and severe form of the disease. cd DN T-cells from TB patients also display an activated phenotype compared with healthy donors. Thus, overall, the DN T population from TB-infected patients presented a profile compatible with previous antigen exposure (HLA-DR) and recent activation (CD69). Host effector immune response against M. tuberculosis is related to the presence of a strong Th1 response and memory, leading to the production of immune mediators that activate parasiteinfected macrophages for parasite destruction. One critical cytokine for host control of M. tuberculosis is 23727046 IFN-c. IFN-c is required for induction of NO synthase type 2 and other effector molecules in infected macrophages. Both CD4+ and CD8+ T-cells and NK cells have been shown to be sources of this protective cytokine in M. tuberculosis infection [13,16]. The essential role of IFN-c is evident from the increased risk of tuberculosis in: (i) individuals with deficiency of IFN-c and interleukin-12, which promotes Th1 cell differentiation; (ii) animal models depleted of CD4+ T-cell during the experimental infection; (iii) HIV-infected individuals [25,26]. ab DN T-cells from TB-patients displayed a higher commitment to the production of IFN-c. Moreover they also contained a higher proportion of IFN-c producing cells than the CD4+ and CD8+ ab T-cell population. High frequencies of IFN-c producing cells in TB group are accounted by patients presenting the non-severe form of tuberculosis. A great proportion of ab DN T-cells from nsTB patients are maintain the ability of IFN-c production, which is lost for sTB patients. The reduction of TB-specific T-cells and the impairment of Th1 immune responseRole of CD4-CD8-ab and cd T Cells in TuberculosisFigure 3. Higher frequencies of IFN-c producing DN ab T-cells are found in nsTB patients. Representative contour plots showing the proportions of IFN-c producing CD4 (left panel), CD8 (middle panel) and DN (right panel) ab-T cells (A). The percentages of IFN-c (B), TNF-a (C) and IL10 (D) expression within CD4+ (left panels), CD8+ (middle panels) and DN (right panels) ab T-cells in healthy donors (HD, open symbols), TB (total TB, black 1317923 symbols), nsTB (non-severe TB, light gray symbols) and sTB patients (severe TB, dark gray) were measured before treatment. PBMCs were stimulated with (MTB-Ag) for 48 hours. The boxes represent the means. doi:10.1371/journal.pone.0050923.gRole of CD4-CD8-ab and cd T Cells in TuberculosisFigure 4. DN cd T-cells from nsTB patients produce inflammatory cytokines whereas those from sTB produce more IL-10. Representative contour plots showing the proportions of IFN-c producing CD4 (left panel), CD8 (middle panel) and DN (right panel) cd-T cells (A). Percentages of IFN-c (B), TNF-a (C) and IL-10 (D) within CD4+ (left panels), CD8+ (middle panels) and DN (right panels) cd T-cells in healthy donors (HD, open symbols), TB (total TB, black symbols), nsTB (non-severe TB, light gray symbols) and sTB patients (severe TB, dark gray) were measured before treatment. PBMCs were stimulated with (MTB-Ag) for 48 hours. The boxes represent the means. doi:10.1371/journal.pone.0050923.gRole of CD4-CD8-ab and cd T Cells in Tuberculosisin active pulmonary tuberculosis patients were reported before [27,28]. cd DN T-cells not only presented higher frequencies of IFN-c producing cells, but they also c.