Generation of cytotoxic T lymphocytes against modified self in the absence of antigen by interleukin 2-containing preparations.

Spleen cells obtained from normal mice were cultured with interleukin 2 (IL2); no antigen was added. After 4-5 days, these cultures contained effector cells which lysed autologous spleen target cells that were modified with 2,4,6-trinitrobenzene sulfonic acid or fluorescein isothiocyanate. No killing was seen on unmodified spleen target cells. These effector cells were Thy 1+, Lyt 1-, 2+ and were derived from Thy 1+ precursor cells. IL2 preparations induced the generation of such cytotoxic T lymphocytes (CTL) in a dose-dependent manner. IL2-induced CTL were shown to be different from the natural killer (NK) cells augmented by IL2 by virtue of their time of appearance in culture, by cold-target competition, and by different cell-surface markers. These results demonstrate that the IL2 signal may be sufficient for the induction of the differentiation of CTL precursors in the absence of an antigenic signal.