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

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.