Role Of DC In Experimental Autoimmune Encephalomyelitis (EAE)

Objective Establish chronic non-remitting experimental autoimmune encephalomyelitis (EAE)model of C57BL/6mice. Detect the maturity of dentritic cell (DC) and the number ofCD4~+CD25~+Treg by using flow cytometry; the expression of FoxP3mRNA and Ror-γtmRNA by using RT-PCR; the secretion of IL-6and TGF-β in the peripheral blood by usingELISA to explore the immunological mechanism of DC in chronic EAE mouse model.Methods54inbred healthy clean female C57BL/6mice were randomly divided into twogroups: EAE group (n=30) and adjuvant control group (n=24). Each group based on thecourse of the disease was divided into: early onset, peak and chronic stages. EAE group wasimmuned with emulsified MOG35-55polypeptides and complete Freund’s adjuvant (CFA),adjuvant control group with the same amount of PBS instead of MOG35-55. Evaluate clinicalsymptoms; detect the quantity of CD11c~+CD83~+DC and CD4~+CD25~+Treg by flow cytometry;the expression of FoxP3mRNA and Ror-γt mRNA by RT-PCR; the secretion of IL-6andTGF-β in the peripheral blood by ELISA.Result1Mouse model80%mice in EAE group developed a progressive paralysis，the highestclinical score is up to5;adjuvant control group showed no incidence, the clinical score is0.2Flow cytometry The CD11c~+CD83~+DC number of the EAE group in spleen cell suspensionincreased compared to the adjuvant control group (P<0.05); the CD4~+CD25~+Treg number atearly onset and peak of the EAE group in spleen cell suspension decreased compared to the adjuvant control group (P<0.05), but it elevated in chronic stage compared to the adjuvantcontrol group(P<0.05); the results among three stages in adjuvant control group had nosignificant difference (P>0.05), but there was a statistical significance in EAE group (P <0.05),the CD4~+CD25~+Treg number decreased most at the peak stage and increased a lot at the chronicstage. However, the CD11c~+CD83~+DC cell number at the peak stage was most and decreased atthe chronic stage.3Real-time quantitative RT-PCR results The expression of FoxP3mRNA on spleenlymphocytes reduced at onset and peak stage of the EAE group compared to the adjuvantcontrol group (P<0.05), but it increased at the chronic stage compared to the adjuvant controlgroup (P<0.05). The expression of Ror-γt mRNA on spleen lymphocytes increased at onsetstage of the EAE group compared to the adjuvant control group (P<0.05), but there were nosignificant difference at the peak and chronic phase compared to the adjuvant control group(P>0.05).4ELISA The secretion of IL-6and TGF-β in peripheral blood of EAE group had a significantdifference (P<0.05) compared to the adjuvant control group. There was no difference (P>0.05)among three stages in adjuvant control group. However, as for IL-6levels among three stages inEAE group, there was a statistical significance(P <0.05), and gradually decreased as the diseaseprocess; while no significant changes for TGF-β levels in EAE group.Conclusion1The change of Th17/Treg balance plays an important role in the course of disease.Th17cellspromote the process of EAE disease, while CD4~+CD25~+Treg plays a role as suppressor inEAE pathogenesis.2Dendritic cells play a role as modulator in EAE disease process and its maturity is positivelyrelated to the severity of the disease.