Cytolysis of primary PI-9–positive lymphoma cells mediated by CTLs and NK cells. (A) PI-9–positive and HLA-A2–positive lymphoma cells from 5 patients were preloaded with influenza peptide (♦) or HIV peptide (⋄) and coincubated with an influenza-peptide–specific T-cell line for 4 hours without (solid lines) or with (broken lines) 50 nM concanamycin A. Specific cytolysis was detected by propidium iodide assay. One out of 2 experiments is shown. Concordant results were obtained in both experiments. (Bi) Lymphoma cells were coincubated with resting NK cells for 4 hours. Specific cytolysis was detected by propidium iodide assay. (Bii) Degranulation of resting NK cells was determined by CD107a staining after coincubation with lymphoma cells for 5 hours. The degranulation of NK cells was assessed in NK cells of the same donor as in the cytolysis assays shown in subpanel Bi. One out of 2 experiments is shown. Concordant results were obtained in both experiments. (C) Lymphoma cells were coincubated with cytokine-activated NK cells for 4 hours without (♦) or with (⋄) 50 nM concanamycin A. Specific cytolysis was determined by propidium iodide. One out of 2 experiments is shown. Concordant results were obtained in both experiments.