Specific cytotoxicity of a long-term cultured T-cell clone on human autologous mammary cancer cells.

We established an autologous specific T-cell killer clone, TcHMC-1, that has been cultured and has retained its function for over 1 year. TcHMC-1 and target cells (HMC-1-8) were derived from the metastatic pleural effusion of a patient with mammary carcinoma. At culture initiation, pleural exudative lymphocytes (PLEL) already demonstrated a high cytotoxic activity against uncloned HMC-1 breast tumor cell targets but not against autologous fibroblasts and K562 targets, and phenotypically these cells showed 100 and 90% reactivity with OKT3 and OKT8 monoclonal antibodies, respectively. However, at the early phase of cultivation under interleukin 2, PLEL had a relatively high cytotoxicity against some allogeneic tumor cells. Furthermore, the longer these PLEL were cultured with interleukin 2 and stimulated with MMC-treated HMC-1, the less cytotoxic activity of PLEL against HMC-1 targets became. We then cloned PLEL as well as HMC-1 tumor cells, and an autologous pair of TcHMC-1 and a target cell clone, HMC-1-8, was successfully obtained. TcHMC-1 showed more than 60% specific cytotoxicity against HMC-1-8, and it was confirmed, using cold target inhibition assays, that TcHMC-1 did not demonstrate nonspecific cytotoxicity against allogeneic targets as well as the natural killer cell activity. Moreover, we examined the in vivo action of TcHMC-1 against HMC-1-8 cells by the Winn assay using nude mice. The data showed that s.c. injections with a mixture of TcHMC-1 and HMC-1-8 clearly resulted in a failure of tumor development in the nude mice even 12 weeks after injections, whereas mice given injections of HMC-1-8 and allogeneic T-lymphocytes cultured with interleukin 2 developed tumors. The autologous pair of a killer T-cell clone and tumor line could be very useful for future investigations of the specific destruction of autologous tumor cells by cytotoxic T-lymphocytes, including analysis for tumor-specific antigens possibly of rejection type and clonotypic T-cell antigen receptors.