Experimental autoimmune encephalomyelitis inhibited by huangqi guizhi wuwu decoction via th2 cytokine enhancement

Background: Huangqi Guizhi Wuwu decoction (HQGZWW) exhibits good effects when administered to treat multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). Understanding the precise mechanism of this decoction is thus important. Based on the findings of our previous study, the aim of the present study was to understand the role of antigen-specific CD8+ T-cells on the pathogenesis of MS/EAE when HQGZWW is administered as treatment. Methods: Myelin oligodendrocyte glycoprotein (MOG) 35-55-induced mice were administered distilled water, prednisone, and high dose or low dose HQGZWW. After purified CD4+ and CD8+ T-cells were stimulated with the MOG35-55 peptide, proliferation and cytokine secretion assays were performed. To establish the adoptive transfer EAE model, naïve mice were injected with MOG35-55 -CD8+ or CD4+ T-cells. Results: Significant improvements in EAE score and pathology were observed in the high dose HQGZWW and prednisone groups. Compared to the low dose HQGZWW and distilled water groups, lower antigen-specific responses, lower levels of interferon-gamma, and higher levels of interleukin (IL)-4 and IL-10 from CD8+ and CD4+ T cells were observed in the high dose HQGZWW and prednisone groups. Finally, the EAE score was observed to be similar between the high dose HQGZWW group and prednisone group; however, this finding was not observed in the low dose HQGZWW group. Conclusion: Our findings suggest that high dose HQGZWW has similar effects on cell proliferation, cytokine secretion, and EAE score to prednisone, while low dose HQGZWW does not have such effect. The protective role of HQGZWW against EAE might thus depend on the Th2 cytokine secretion profile induced by either MOG35-55 specific CD8+ or CD4+ T-cells.