Identification of a novel WT1‐derived peptide which induces human leucocyte antigen‐A24‐restricted anti‐leukaemia cytotoxic T lymphocytes

Summary. We previously reported the establishment of a Wilms' tumour (WT)1‐derived peptide (CMTWNQMNL)‐specific and human leucocyte antigen (HLA)‐A24‐restricted anti‐leukaemia cytotoxic T lymphocyte (CTL) line, TAK‐1. In this study, we have established a novel WT1‐derived peptide (RWPSCQKKF)‐specific CD8 + CTL line, designated NIM‐1. NIM‐1 lysed HLA‐A24‐positive leukaemia cells, but not HLA‐A24‐negative leukaemia cells or normal cells. The effects of TAK‐1 and NIM‐1 on cytotoxicity against leukaemia cells were not synergistic, suggesting that recognition of a single epitope on the tumour‐specific antigen by CTLs is sufficient to exert maximal cytotoxic activity against tumour cells.