CD8(+) T cell clones produced both interleukin 10 (IL-10) and interferon-gamma (IFN-gamma) when these cells were stimulated with a T cell-specific mitogen, concanavalin A (Con A). One of these CD8(+) T cell clones, 13G2, secreted IFN-gamma at similar levels with calcium ionophore, A23187, as well as by Con A, but IL-10 production by A23187 was less than by Con A. On the other hand, N-6, O-2-dibutyryl cAMP enhanced the production of IL-10 but not IFN-gamma when the low doses of Con A or A23187 coexisted. In a T cell clone, the production of these two cytokines required different signal transductions. These results indicate that a T cell clone can produce diverse cytokines depending on the surrounding condition. (C) 1996 Academic Press, Inc.