Fig. 2.

The effect of Iristatin on T-cell and mast cell cytokine production. a–f Different subpopulations of T-helper cells were preincubated with 6 μM Iristatin and polyclonally stimulated with a combination of CD3 and CD28 mAbs. Cytokine levels were determined 48 h after stimulation. Th cells activated in the absence of Iristatin were used as controls and set as 100% in all experiments; all other values are expressed as percentages of these controls. Iristatin inhibited IFN-γ (a) and IL-2 (b) production by Th1 cells. c Iristatin strongly reduced IL-4 production by Th2 cells. Iristatin inhibited IL-2 (d) and IL-9 (e) production by Th9 cells. f The inhibition of IL-17 production by Th-17 cells was not significant. g–i Mast cells were pretreated with Iristatin and stimulated with ionomycin. Cytokine levels were measured 48 h after stimulation. g IL-4 production was not affected by Iristatin treatment. h 6 μM Iristatin inhibited IL-6 production by mast cells. i Iristatin strongly inhibited IL-9 production by mast cells. The mean of three independent experiments (± SEM) is shown in all graphs. *P ≤ 0.05; **P ≤ 0.01; ***P ≤ 0.001; ****P ≤ 0.0001; n.s. not significant