Figure 4. Survivin-specific TCR–redirected T cells have antitumor activity in vitro, while lacking toxicity against normal hematopoietic stem/progenitor cells.

(A) ⁵¹Cr-release assays of survivin-specific TCR⁺ TD (white squares) and NT control T cells (black circles) against HLA-A*02⁺survivin⁺ cancer cell lines BV173 and U266 and the HLA-A*02^–survivin⁺ targets HL-60 and K562. Symbols indicate the mean of triplicates per donor; error bars represent the mean ± SD of the percentage of specific lysis at an E/T ratio of 20:1 (n = 12 donors). *P < 0.001; **P = 0.003 by Student’s t test. (B) HLA restriction of TCR⁺ TD (white symbols) and NT T cells (black symbols) assessed by preincubation of BV173 (left panel, triangles) or U266 (right panel, circles) with HLA class I–blocking Ab (dotted lines), HLA class II–blocking Ab (dashed lines), or in the absence of Ab (solid lines). Data represent the mean ± SD of 3 technical replicates from 1 donor. Cells from 2 donors were analyzed. (C) Quantification of residual tumor cells in cocultures on day 5 of TCR⁺ TD (open squares) and NT (black circles) T cells cultured with BV173, U266, K562, and HL-60 cells (E/T 5:1). Mean ± SD of residual tumor cells (n = 6). *P < 0.001 and ** P = 0.02 by Student’s t test. (D) IFN-γ production by TCR⁺ TD (white squares) and NT (black circles) T cells against BV173, U266, K562, and HL-60 cells by ELISpot assay. Symbols represent the mean of triplicates per donor; error bars indicate the mean ± SD (n = 5). *P < 0.001 and **P = 0.01 by Student’s t test. (E–G) Assessment of leukemic colony formation by TCR⁺ TD (white squares) and NT (black circles) T cells against HLA-A*02⁺ CML blast crisis (n = 2) and AML (n = 3) (E), HLA-A*02^– leukemic blasts (F), and HLA-A*02⁺ healthy donor–derived BM (n = 1) or CB (n = 4) progenitor cells (G). Data represent the mean ± SD of CFU plated in duplicate for 5 donors. *P < 0.001 by Student’s t test.