Evidence for cytotoxic functions in well-defined human T cell clones.

Long-term cultures of T lymphocytes from PBL of normal individuals and cancer patients grown in presence of TCGF exhibited cytotoxic activity directed against a variety of targets. In order to separate the subpopulations responsible for the different cytotoxic activities, cultured T lymphocyte cloning was performed. Production of T cell clones were obtained at a high yield by direct isolation and culture of single T cells. Preliminary analysis of cell-mediated cytotoxicity showed that 8 out of 11 clones were cytotoxic against both PHA pretreated L1210 and K562 target cells. In addition, within a clone, only a percentage of cells expressed the cytotoxic function. We suggested that this finding is due to the different stage of maturation of the cloned cells and this hypothesis correlate with their morphology, which is not identical for all the cells within a clone.