Figure 1.

Suppression of Th2 cell-mediated features of allergic inflammation by T_Reg cells. T_Reg cells utilize multiple suppressor factors to regulate undesired activity of effector Th2 cells. IL-10 and TGF-β suppress IgE production and induce the non-inflammatory immunoglobulin isotypes IgG4 and IgA, respectively. Furthermore, these two cytokines directly suppress allergic inflammation induced by effector cells such as mast cells, basophils and eosinophils. In addition, Th2 cells are suppressed by T_Reg cells and can therefore no longer provide cytokines such as IL-3, IL-4, IL-5, IL-9 and IL-13. These cytokines are required for the differentiation, survival and activity of mast cells, basophils, eosinophils and mucus-producing cells, as well as for the tissue homing of Th2 cells (red line indicates suppression, black line indicates stimulation).