Figure 6: Purity and reactivity of sorted and amplified T cells. (a) Purity of sorted and amplified T cell populations is assessed by double staining with an anti-CD8 specific mAb and each specific HLA-p tetramers. (b) Activity of sorted T cells is measured by TNF production in response to the cognate peptide or to HLA-A2 melanoma cell lines expressing Melan-A and MELOE-1 antigens. After activation, T cells are stained with their specific HLA-p tetramer, and TNF producing cells are visualized by intracellular staining with an anti-TNF mAb. Blue histograms represent Melan-A- specific T cells and red ones MELOE-1-specific T cells.