All participants were recruited between May 2008 and March 2009 at the Ottawa Hospital, Ontario, Canada. The participants were classified into three groups, namely healthy controls, latent TB and active TB. The demographic data including age, gender and ethnicity are listed in Table 1. Eleven participants who were tested negative to tuberculin skin test (TST), which was defined as having

induration of ≤5 mm, were considered to be healthy controls. Twenty-four participants with latent TB infection were diagnosed Dorsomorphin by positive TST (induration ≥10 mm) without any clinical and radiological evidence of active disease. Nine active TB patients were diagnosed on the basis of positive acid-fast bacilli staining and culture from sputum, bronchoalveolar

lavage or lymph nodes. Two patients had extrapulmonary Romidepsin supplier tuberculosis (TB lymphadenitis and cystitis). None of the latent TB individuals had any active infections at the time of blood acquisitions. All participants with latent and active TB infection were enrolled prior to receiving medication for tuberculosis. All participants were HIV seronegative. Informed consent was given by all participants based on the study protocol, which was approved by the Research Ethics Boards of the Ottawa Hospital Research Institute. The peripheral heparinized blood (20–30 ml) was collected and used for whole blood cytokine assay and for PBMC intracellular cytokine assay. M. bovis culture filtrate (CF) was a gift from Dr Bryan D. Rennie (Health

Canada, Ottawa, Ontario, Canada). This culture Protirelin filtrate is 99% identical to M. tuberculosis. Phorbol 12-myristate-13 acetate (PMA) (Sigma-Aldrich, St Louis, MO, USA) and ionomycin (Invitrogen, Burlington, Ontario, Canada) were used to stimulate cells as a positive control in a whole blood assay. The following antibodies were used for surface and intracellular staining: anti-human-CD3-fluorescein isothiocyanate (FITC), IFN-γ-FITC, CD8-phycoerythrin (PE)-Texas Red (ECD), CD14-ECD (Beckman Coulter, Mississauga, Ontario, Canada); CD4-allophycocyanin and cyanin (APC Cy7), CD8-PE, CD25-PE, IL-22-PE, IL-17-APC Cy7 (R&D Systems, Minneapolis, MN, USA) and CD15-FITC (Sigma-Aldrich). Anti-CD4-APC Cy7 antibody listed above was used in all experiments gating for CD4 T cells. Up to five antibodies were used in each experiment.