Heparinized whole blood was usually

received from TB clinics in the late afternoon. Blood was then kept overnight at room temperature on a rocker. Whole blood (1 ml) was cultured the next day in the morning at 37°C, 5% CO2 in 24-well tissue culture plate with or without PMA (50 ng/ml)/ionomycin (1 µg/ml) for 4 h in the presence of BD GolgistopTM (BD Biosciences, Mississauga, Ontario, Canada). The whole blood (40 µl) was incubated with saturating concentration of appropriate fluorochrome-labelled antibodies. Cell fixation, permeabilization and RBC lysis were performed using IntraprepTM permeabilization solution (Beckman Coulter), as described by the manufacturer. Generally, 20 000 leucocytes were acquired. Cells were R788 clinical trial analysed by Cytomics FC 500 MPL (Beckman Coulter) using CXP Analysis software. PBMCs (1 × 106 cells/ml) isolated from peripheral blood by centrifugation PD0325901 on Ficoll-Hypaque Plus (Amersham Bioscience, Pittsburgh, PA, USA) were cultured in RPMI-1640 medium (Invitrogen) containing 10% serum at 37°C

in 24-well tissue culture plate with or without mycobacterial culture filtrate (5 µg/ml) for 7 days. BD GolgistopTM was added 4 h prior to the cell staining. Cultured PBMCs (100 µl) were incubated with appropriate fluorochrome-labelled antibodies to surface molecules for 15 min at room temperature in the dark. Stained cells were washed with phosphate-buffered saline (PBS) containing 0·1% sodium azide and 0·5% fetal bovine serum (FBS). Cells were then fixed and permeabilized with Hanks’s buffered salt solution containing 4% paraformaldehyde and

0·1% saponin for 15 min and subsequently washed twice with PBS containing 0·1% saponin, 0·1% sodium azide and 0·5% FBS. Fluorochrome-labelled anti-cytokine antibodies were then added. Cells were washed again after 15 min incubation and suspended in 300 µl of 1% paraformaldehyde in PBS. IL-17+, IL-22+ and IFN-γ+ CD4+ T cells were quantified by flow cytometry using CXP analysis software. For cytokine quantitation, supernatants were collected from 7-day-old M. bovis-stimulated and -unstimulated PBMC cultures. Serum was collected from the blood samples obtained from 11 healthy TST non-responders, Atazanavir 21 individuals with latent TB infection and nine patients with active TB infection. Cytokine levels were measured using the FlowCytomix human Th1/Th2 11plex kit, IL-17A and IL-22 simplex kits (Bender Medsystems GmbH, Vienna, Austria), as per the manufacturer’s instructions. The detection limit for IFN-γ, IL-17A, IL-22, IL-8, IL-6, TNF-α, IL-1β, IL-4, IL-5, IL-10, IL-2, IL-12p70 and TNF-β were 1·6, 2·5, 43·3, 0·5, 1·2, 3·2, 4·2, 20·8, 1·6, 1·9, 16·4, 1·5 and 2·4 pg/ml, respectively. Data were analysed using FlowCytomixTM Pro 2·3 software.