Generation of natural killer-like cytotoxicity from human thymocytes with interleukin-2.

Human thymocytes cultured in the presence of an interleukin-2 (IL-2) source (the supernatant of the MLA 144 cell line) that contains no lectin or interferon (IFN) activity become cytotoxic to K562 target cells. Inclusion of allogeneic lymphoblastoid cells in these cultures results in the earlier detection of cytotoxic activity. Addition of IFN to the thymocyte cultures has no effect on the development of cytotoxic activity. In contrast, the cytotoxic activity of IL-2 activated thymocytes can be augmented by subsequent exposure to IFN. The specificity and cell surface phenotype of the cytotoxic thymocytes are similar to that of peripheral blood natural killer cells.