Figure 2. Cytotoxic activity of a healthy donor-derived PRAME_100–108-specific cytotoxic T lymphocyte clone toward leukemic cell lines and patient samples. (A and B) Cytotoxic activity of a healthy donor-derived PRAME_100–108-specific cytotoxic T lymphocyte (CTL) clone against chronic myeloid leukemia (CML) PRAME⁺ K562 cells (either HLA-A2^- or upon transduction with HLA-A2), acute myeloid leukemia (AML) PRAME^-HLA-A2⁺ ME1 cells, unloaded JY cells and PRAME_100–108-loaded JY cells, as monitored in a flow cytometry-based assay with 10:1 effector-to-target (E:T) cell ratios. (B) Cytotoxic activity of PRAME_100–108-specific CTLs against HLA-A2-expressing K562 (K562-A2⁺) cells, in the presence of an MHC class I-blocking antibody (MHC) or appropriate isotype control antibodies (iso). (A) and (B) depict the percentage of viable cells upon incubation with PRAME_100–108-specific CTLs. (C and D) Percentage of viable MUTZ-3 cells (C) and patient-derived AML cells (one representative example out of two HLA-A2 matched patients tested) (D) upon incubation with PRAME_100–108-specific CTLs at the indicated E:T cell ratios.