LrB inhibits IL-2 secretion from activated Jurkat T cells. The concentrations of IL-2 in cell growth media were measured by ELISA. Jurkat T cells were activated by PHA (10 μg/ml) for 24 hours. LrB (30 and 100 μM), CP-339818 (CP, 3 and 10 μM) were added simultaneously with PHA. **P < 0.01, ***P < 0.0001, n = 6.