Antigen-specific lysis of human tumor cell lines endogenously expressing survivin. Human renal cell carcinoma (MZ 1774, MZ 1257, A 498), melanoma (Mel 1479), breast cancer (MCF-7), multiple myeloma (U 266), and the EBV-immortalized Croft cells expressing survivin and HLA-A2 as well as the ovarian cancer cell line SK-OV-3 (HLA-A2^-/survivin+) were used as targets in a standard ⁵¹Cr-release assay. K 562 cells were included to determine the NK cell activity (A-C). The HLA-A2 restriction of the CTL lines was analyzed using a HLA-A2–specific monoclonal antibody (U 266 + anti–HLA-A2, 3C; A498 + anti–HLA-A2, 3D). An isotype antibody was used as control (control immunoglobulin). A cold target inhibition assay was performed to analyze the antigen specificity of the CTL lines (D). Unlabeled T2 cells pulsed with the cognate survivin peptide were used to block lysis of A 498 cells (A 498 + T2 + Sv). No inhibition of lysis was detected when using T2 cells pulsed with the irrelevant adipophilin peptide (A 498 + T2 + Ad). The ratio of inhibitor to target cells was 20:1.