Two ml 0·5% bovine serum albumin (Sigma, St Louis, MO, USA) in IsoFlow (Beckman

Coulter, Lane Cove, NSW, Australia) was then added and the tubes centrifuged at 300 g for 5 min. After decanting supernatant, Fc receptors were blocked with 10 μl human immunoglobulin (Intragam, CSL, Parkville, Australia) check details for 10 min at room temperature. Five μl of appropriately diluted anti-CD8 FITC (BD), anti-CD3 PerCP-Cy5·5 (BD), CD28 PE-Cy7 (BD) and PE-conjugated granzyme B (BD), 10 μl undiluted perforin (BD) or isotype control monoclonal antibody was added for 15 min in the dark at room temperature. Cells were analysed within 1 h. Samples were analysed by live gating using FL3 staining versus side-scatter (SSC). A minimum of 10 000 CD3-positive, low-SSC SP600125 datasheet events were acquired in list-mode format for analysis. Control staining of cells with anti-mouse immunoglobulin (Ig)G1-PE/IgG-PC5 was performed on each sample and background readings of < 2% were obtained as described previously

[8]. Significant co-stimulatory molecule expression on T cells other than CD28 requires T cell stimulation similar to that required for intracellular cytokine production [14]. For CD154, CD152, CD137 and CD134, 1-ml aliquots of blood (diluted 1:2 with RPMI-1640 medium) were placed into 10 ml sterile conical polyvinyl chloride (PVC) tubes (Johns Professional Products, Sydney, Australia). Phorbol myristate (25 ng/ml) and ionomycin (1 mg/ml) were added to stimulate the T cells.

Brefeldin A (10 mg/ml) was added to prevent shedding of Y-27632 2HCl the co-stimulatory molecules from the T cell surface, as reported previously [15]. The tubes were incubated in a humidified 5%CO2/95% air atmosphere at 37°C. At 16 h 100 ml 20 mM ethylenediamine tetraacetic acid/phosphate-buffered saline (EDTA/PBS) was added to the culture tubes, which were vortexed vigorously for 20 s to remove adherent cells. Three hundred microlitre aliquots of cells were treated with 2 ml FACSLyse for 10 min. Cells were centrifuged, supernatant discarded and 500 ml FACSPerm added for 10 min. Two ml 0·5% bovine serum albumin (BSA) (Sigma) in IsoFlow (Beckman Coulter) was then added and the tubes centrifuged at 300 g for 5 min. After decanting supernatant, Fc receptors were blocked with 10 ml human immunoglobulin (Intragam, CSL, Parkville, Victoria, Australia) for 10 min at room temperature. Five μl of appropriately diluted CD8 FITC [allophycocyanin (APC)-Cy7], CD3 PerCP-Cy5·5 (BD), CD28 PE-Cy7 (BD), CD45 V450 (BD) and PE-conjugated monoclonal antibodies to CD40L, CD152, CD137, CD134 or isotype control (BD) were added for 15 min in the dark at room temperature. Cells were washed and events acquired and analysed as described above.