Human normal CTL clones: Generation and properties

This study reports the production of clones of human killer T cells grown in the presence of TCGF 4 following sensitization in MLC against (1) allogeneic cells, (2) autologous B ebv+ lymphocytes, or (3) autologous lymphoma cells. Sensitization against the tumor cells required the addition of macrophages. The expression of the cytotoxic activity of the cloned T lymphocytes required re‐stimulation with the specific stimulator cells. The cytotoxic activity seemed to be MHC‐restricted, since (1) cloned allosensitized CTL lysed their corresponding allogeneic targets, but did not lyse autologous B ebv+ cells or K562 cells; (2) cloned CTL sensitized against autologous B ebv+ cells lysed their autologous targets but not allogeneic B ebv+ targets or K562 cells; and (3) cloned CTL sensitized against autologous Burkitt lymphoma cells lysed their corresponding lymphoma targets or autologous B ebv+ targets but did not lyse allogeneic lymphoma cells or B ebv+ cells from the same allogeneic donors. The cloned CTL were homogeneous in expressing the OK T8 molecules and in being negative for T4, T10 or M1. At any given time, 25‐45% of the cloned cells manifested lytic activity. The ultrastructural properties and cell surface OK T markers were different from those of cloned human NK cells. Emphasis is focused on the differences between the structural, functional and culture characteristics of CTL clones produced by direct isolation of MLC responder cells forming conjugates with specific target cells and those of clones from transformed T‐cell lines or from T hybridomas.