Characterization of myelin oligodendrocyte glycoprotein (MOG)35–55- specific CD8^+ T cells in experimental autoimmune encephalomyelitis

Background:The pathogenesis of multiple sclerosis(MS)is mediated primarily by T cells,but most studies of MS and its animal model,experimental autoimmune encephalomyelitis(EAE),have focused on CD4^+ T cells.The aims of the current study were to determine the pathological interrelationship between CD4 and CD8 autoreactive T cells in MS/EAE.Methods:Female C57BL/6 mice(n=20)were induced by myelin oligodendrocyte glycoprotein(MOG)35-55 peptide.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-γ)and interleukin(IL)-4 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:CD8^+ CD3^+ and CD4^+ CD3^+ cells were 86%and 94%pure of total CD3^+ cells after CD8/CD4 bead enrichment,respectively.These cells were stimulated by MOG35–55 peptide and applied to proliferation assays.Although the CD8^+ T cells had a generally lower response to MOG35–55 than CD4^+ T cells,the response of CD8^+ T cells was not always dependent on CD4.CD8^+ T cell secreted less IFN-γand IL-4 compared with CD4^+ T cells.EAE was induced in wildtype B6 na?ve mice by adoptive transfer of MOG35–55-specific T cells from B6 active-induced EAE(aEAE)mice.A similar EAE score and slight inflammation and demyelination were found in naive B6 mice after transferring of CD8^+ T cells from immunized B6 mice compared with transfer of CD4^+ T cells.Conclusion:Our data suggest that CD8^+ autoreactive T cells in EAE have a lower encephalitogenic function but are unique and independent on pathogenic of EAE rather than their CD4^+ counterparts.

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 pathogene sis of MS/EAE when HQGZWW is administered as treatment.Methods:Myelin oligodendrocyte glycoprotein(MOG);-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 MOG;peptide,proliferation and cytokine secretion assays were performed.To establish the adoptive transfer EAE model,naive mice were injected with MOG;-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 re sponses,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 MOG;specific CD8^(+)or CD4^(+)T-cells.