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.

Multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), a pathologically similar disease used to model MS in rodents, are typical CD4+ T cell-dominated autoimmune diseases. CD4+ interleukin (IL)17+ T cells (Th17 cells) have been well studied and have shown that they play a critical role in the pathogenesis of MS/EAE. However, studies have suggested that CD8+IL17+ T cells (Tc17 cells) have a similar phenotype and cytokine and transcription factor profiles to those of Th17 cells and have been found to be crucial in the pathogenesis of autoimmune diseases, including MS/EAE, psoriasis, type I diabetes, rheumatoid arthritis, and systemic lupus erythematosus. However, the evidence for this is indirect and insufficient. Therefore, we searched for related publications and attempted to summarize the current knowledge on the role of Tc17 cells in the pathogenesis of MS/EAE, as well as in the pathogenesis of other autoimmune diseases, and to find out whether Tc17 cells or Th17 cells play a more critical role in autoimmune disease, especially in MS and EAE pathogenesis, or whether the interaction between these two cell types plays a critical role in the development of the disease.

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Background: Current modern conventional medicine (MCM) on multiple sclerosis (MS) are non-specific immunosuppressive drugs, which remains many side effects. Huangqi Guizhi Wuwu decoction (HQGZWW) is a common formula of Chinese herbal medicine (CHM) has good effects on treatment of MS and its animal model, experimental autoimmune encephalomyelitis (EAE) very well, so it is very important to understand the precise mechanism. Our previous study suggested that CD8+ autoreactive T cells in EAE had a lower encephalitogenic function but were unique and independent on pathogenic of EAE rather than their CD4+ counterparts. The aims of current study were to determine the pathological interrelationship between CD4+ and CD8+ autoreactive T cells in MS/EAE upon the HQGZWW treatment.Methods: Female C57BL/6 mice (n=8, each group) were induced by myelin oligodendrocyte glycoprotein (MOG)35-55 peptide, and meantimely were treated with distilled water, prednisone, high dose or low dose HQGZWW. At 14 days after immunization, T cells were isolated from the spleen and purified as CD4+ and CD8+ T cells by using CD4 and CD8 isolation kits, and then the purity was determined by flow cytometric analysis. These cells were stimulated by MOG35-55 peptide and applied to proliferation assays. The interferon-gamma (IFN-g), interleukin (IL)-4 and IL-10 secretion of supernatant of cultured CD4+ and CD8+ T cells were measured by enzyme-linked immunosorbent assays (ELISA). For adoptive transfer, recipient mice were injected with MOG35-55 -specific CD8+ or CD4+ T cells. EAE clinical course was measured by EAE score at 0-5 scale and spinal cord was examined by staining with hematoxylin and eosin and Luxol fast blue staining.Results: For aEAE, there were significant improvement of EAE score in both HQGZWW high dose and prednisone groups by EAE score and pathological examination of spinal cord. CD8+ CD3+ and CD4+CD3+ cells were around 90% pure of total CD3+ cells after CD8/CD4 bead enrichment in 4 groups, respectively. These cells were stimulated by MOG35–55 peptide and applied to proliferation assays. There is lower antigen-specific responses of CD8+ as well as CD4+ T cells in HQGZWW high dose and prednisone group, compared with HQGZWW low dose and distilled water groups. For cytokine profiles, the CD4+ and CD8+ T cell supernatants contained lower levels of IFN-g and higher levels of IL-4 and IL-10 in HQGZWW high dose and prednisone groups compared with HQGZWW low dose and distilled water groups. Finally, HQGZWW had similar effect at high dose level to typical conventional medicine prednisone on tEAE, but no effect at low dose level.Conclusion: Our data suggested that HQGZWW had similar effect at high dose level to typical conventional medicine prednisone on EAE, but no effect at low dose level, and it suggested that the protection role of HQGZWW on EAE might be upon Th2 cytokine secretion profile by either MOG35–55 specific CD8+ or CD4+ T cells.