Suppression assay
After expansion Treg were stained with eFluor 670 Cell Proliferation Dye and co-cultured with CFSE stained, FACS sorted, allogenic CD8+ T cells at 1:1, 1:2, 1:4, 1:8 and 1:0 Tcell:Treg ratios in the presence of anti CD3/CD28 beads at 1:10 cell/bead ratio. Cell culture was harvested at day 5 and the percentage of proliferating (CFSE diluted) T cells was calculated. The percentage of suppression was calculated as 100-[100 x (percentage of proliferating cells with Treg present)/(percentage of proliferating cells without Tresp present)].