Cellular origin of interleukin 2 (IL 2) in man: evidence for stimulus-restricted IL 2 production by T4+ and T8+ T lymphocytes.

The human T cell subset(s) responsible for production of interleukin 2 (IL 2) was investigated in the present study. For this purpose, highly purified T4+ and T8+ T lymphocytes were stimulated with mitogens and alloantigens. Subsequently, culture supernatants were analyzed for IL 2 activity in each of two assay systems: 1) proliferation of long-term T cell lines and 2) induction of cytotoxic effector cells from a resting T8+ population incubated in MLC. Mitogen stimulation led to secretion of equivalent amounts of IL 2 from both the major T cell subsets; in contrast, after allogeneic activation, IL 2 was produced predominantly from the T4+ subset. The stimulus dependency of IL 2 production suggests that the individual functional repertoires of T4+ and T8+ T cell subsets may be linked to unique surface receptors and/or interaction molecules involved in cell triggering rather than a restricted capacity to produce lymphokine.