Evaluation of the potential 9mer CTL epitope within p117-139.

The p117-139 tumor-specific CTL line was tested against peptides within p117-139 containing or lacking an appropriate H-2^b class I binding motif and after restimulation with p126-134 or p130-138. Lines represent the mean percentage specific lysis and standard deviations in chromium release assays performed in triplicate with E:T ratios of 25:1, 5:1, and 1:1. (A) Cytotoxic activity of the p117-139–specific T-cell line against the WT1-negative cell line EL-4 pulsed with the peptides p117-139 (EL-4 + p117-139), p119-127 (EL-4 + p119-127), p120-128 (EL-4 + p120-128), p123-131 (EL-4 + p123-131), p126-134 (EL-4 + p126-134), p128-136 (EL-4 + p128-136), and p130-138 (EL-4 + p130-138). (B) Cytotoxic activity of the CTL line after restimulation with p130-138 against EL-4, EL-4 cells pulsed with p117-139 (EL-4 + p117-139), p130-138 (EL-4 + p130-128), and the WT1-positive tumor cell lines BLKSV40 and TRAMP-C.