Cytotoxic activity of DYS specific T-cell clones. (A) HLA-DRB*0701–positive or HLA-DRB*0701–negative LCL targets were pulsed with DYS peptide and incubated with unmanipulated or ConA-treated, DYS-specific CD4⁺ T-cell clones. Cytotoxicity was measured by chromium release assay. (B) Flow cytometric demonstration of intracellular perforin and granzyme B expression by DYS-specific CD4⁺ T-cell clones. Fibroblasts (C) or DCs (D) infected with CMV strains AD169 or RV798 are killed by DYS-specific T-cell clones. Cytotoxicity was measured using the chromium release assay.