Evaluation of degranulation and IFN-γ production in CD8⁺ T cells of HTLV-I–infected patients. (A) Titration of Tax11-19 peptide stimulation to induce degranulation and IFN-γ production in CD8⁺ T cells of 2 HLA-A*201 ACs (AC#2 and 4) and 3 HLA-A*201 HAM/TSP patients (HAM#2, 4 and 5). CD107a/IFN-γ expression was analyzed after 5 hours stimulation with peptide. (B) CD107a mobilization and expression of intracellular IFN-γ, perforin and granzyme B in HTLV-I–specific CD8⁺ T cells of a HAM/TSP patient. The graph shows the percentage of Tax tetramer⁺ CD8⁺ T cells in unstimulated culture for 5 hours (□), unstimulated for 24 hours (), and stimulated with Tax11-19 peptide for 5 hours (■).