Development of adoptive immunotherapy with KK‐LC‐1‐specific TCR‐transduced γδT cells against lung cancer cells

The present study analyzed the antitumor effect of γδT cells transduced with the TCR of cancer‐specific CTLs to establish forceful cancer‐specific adoptive immunotherapy. We cloned the TCRαβ genes from CTLs showing HLA‐B15 restricted recognition of Kita‐Kyushu lung cancer antigen‐1 (KK‐LC‐1), a cancer/germline gene antigen, identified in a lung adenocarcinoma case (F1121). The TCRαβ and CD8 genes were transduced into γδT cells induced from PBLs of healthy volunteers stimulated with zoledronate and IL‐2. The KK‐LC‐1‐specific TCRαβ‐CD8 γδT cells showed cytotoxic activity against the KK‐LC‐1 positive lung cancer cell line F1121L and produced IFN‐γ against F1121L and KK‐LC‐1 peptide‐pulsed F1121 EBV‐B cells. These responses were blocked by HLA class I and HLA‐B/C antibodies. An in vivo assay using NOD/SCID mice with xenotransplantation of human lung cancer cells was performed, and the TCRαβ‐CD8 transduced γδT cells (TCRαβ‐CD8 γδT cells) were intravenously injected. Growth inhibition of KK‐LC‐1+, HLA‐B15+ lung cancer cells was confirmed in mice with injection of the TCRαβ‐CD8 γδT cells from 1 wk after xenotransplantation of cancer cells but not in those treated 2 wk after xenotransplantation. The resected specimens of the tumor, 2 wk after xenotransplantation, highly expressed FasL but not programmed death ligand‐1 (PD‐L1) by immunohistochemical staining. FasL highly expressed cancer cells xenotransplanted 2 wk ago were resistant to TCRαβ‐CD8 γδT cells injection. These results suggested that apoptosis of Fas‐positive TCRαβ‐CD8 γδT cells may be induced by a Fas‐mediated signal after interacting with FasL‐positive cancer cells. (1) Kita‐Kyushu lung cancer antigen‐1 (KK‐LC‐1)‐specific cytotoxicity, which is the same as that observed in CTL clones, was obtained by transducing KK‐LC‐1‐specific TCRαβ and CD8 cells into γδT cells. (2) An in vivo assay using NOD/SCID mice with xenotransplantation of human lung cancer cells was performed, and the TCRαβ‐CD8 transduced γδT cells were intravenously injected. Growth inhibition of KK‐LC‐1+, HLA‐B15+ lung cancer cells was observed in mice with tumors 1 wk after xenotransplantation but not in those mice with tumors 2 wk after xenotransplantation. (3) Cancer cells expressed a high level of FasL at 2 wk after xenotransplantation and escaped adoptive treatment. We should be alert for Fas‐mediated apoptosis when applying such cellular immunotherapy.