T cell response to embryonal carcinoma F9 cells: induction and characterization of T cell receptor alpha beta+ double-negative cytotoxic T lymphocytes.

We investigated the mechanism of T cell response to murine embryonal carcinoma F9 cells. Thy-1+, CD4-, CD8- (double-negative) cytotoxic effector cells were induced in spleen cells obtained from immune A.BY mice to F9 cells, and the cytotoxic activity was major histocompatibility complex (MHC)-unrestricted. Furthermore, CD4+ T cells were essential for the induction of double-negative cytotoxic T lymphocytes directed to F9 cells. Most of the double-negative cytotoxic T lymphocyte lines obtained by long-term culture of the effector cells had CD3 molecule and T-cell receptor beta chain on their cell surface, and the CD3 molecule was found to be involved in target cell recognition. The T cell receptor alpha beta+ double-negative cytotoxic T lymphocyte line (2A5) also lysed various tumor cells in a non-MHC-restricted manner, but did not lyse concanavalin A-stimulated blasts of 129 strain, from which F9 cells had originated. These results indicate that T cell receptor alpha beta+ double-negative cytotoxic T lymphocytes induced by F9 cells recognize a common antigen(s) expressed on F9 cells and other tumor cells but not minor histocompatibility antigens.