Isolation and Culture of Human T Cells

The isolation of human T cells from PBMC was performed as recently described [45] , using either a Pan T cell Isolation Kit (Miltenyi Biotec GmbH, Bergisch Gladbach, Germany) or the PluriSelect CD3⁺ Isolation Kit (PluriSelect GmbH, Leipzig, Germany). T cells were cultured in RPMI 1640 complete medium supplemented with 200 U/ml IL-2 (Proleukin S, Novartis Pharmaceuticals, Horsham, UK), 5 ng/ml IL-7 and 5 ng/ml IL-15 (ImmunoTools, Friesoythe, Germany) at 37°C in a humidified atmosphere of 5% CO₂ at densities of 1−2*10⁶ cells/ml. T cells were starved in complete RPMI 1640 without recombinant cytokines 24h before experiments were performed.