Upregulation of Th1 Polarization by Taraxacum officinale in Normal and Immune Suppressed Mice

The present study was undertaken to study the potential of Taraxacum officinale aqueous extract (aerial part; TO-10) to maintain immune homeostasis in normal and chronic restraint stress and cyclosporine-A-induced immune suppressed mice. Immune restorative effect of test drug was evaluated first in normal and then in immune-compromised mice using flow cytometer and Elisa techniques. TO-10 enhanced the expression of T-cell subsets and CD28, CD69 and CD80/CD86 co-stimulatory molecules in sheep red blood corpuscles (SRBCs)-immunized mice. Flow cytometric analysis revealed that TO-10 upregulated the expression of Th1 cytokines, IL-2, IFN-gamma and IL-12, and regularized the increased expression of IL- 10 in chronically stressed animals. It also normalized the elevated corticosterone levels, and reversed the chronic stress-induced hypertrophy of adrenal glands and atrophy of spleen and thymus. The results show that TO-10 is also able to maintain immune homeostasis in normal and immune-compromised conditions. Chicoric acid, a major constituent of TO-10, seems to be responsible for skewing to Th1 immune polarization as shown by its stimulatory effect on the expression of IFN-gamma and IL-2 in phorbol 12-myristate 13-acetate + ionomycin stimulated peripheral blood mononuclear cells (PBMCs).