ODN 2216 (CpG-A) increases the granzyme-B content and lytic activity of peptide-specific T-cell clones through IFN-α/-β. HLA-A2–restricted Melan A_26-35 A27L peptide-specific T-cell clones were generated as described in “Materials and methods” and were incubated in the presence of supernatants derived from PBMCs stimulated with 6 μg/mL ODN 2006, ODN 2216, ODN 2243, or with medium. After 18 hours, the clones were harvested, washed, and used as effector cells in a standard ⁵¹Cr release assay against T2 cells pulsed with their cognate peptide or as a control peptide derived from the HIV pol protein (A-C) or stained for their intracellular granzyme-B content and analyzed by flow cytometry (D). Results in percentage specific lysis represent the mean of triplicate measurements from which the nonspecific lytic activity (percentage specific lysis of T2 cells pulsed with the control peptide) has been subtracted. (A) Results of 1 representative experiment of a Melan A_26-35A27L–specific clone at different E/T ratios are shown. (B) Data from different Melan A_26-35A27L–specific clones at an E/T ratio of 30:1 are depicted. *P < .05. (C) Data from 4 different clones are depicted as mean ± SEM. *P < .05. (D) Percentages of granzyme-B–positive cells from 2 clones are shown as mean ± SEM. Blocking antibodies were added at the beginning of the 18-hour incubation period in ODN 2216-induced supernatant.