1,25‐dihydroxyvitamin D3‐induced dendritic cells suppress experimental autoimmune encephalomyelitis by increasing proportions of the regulatory lymphocytes and reducing T helper type 1 and type 17 cells

Summary Dendritic cells (DCs), a bridge for innate and adaptive immune responses, play a key role in the development of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), an animal model forMS. Administration of tolerogenicDCs has been used as an immunotherapy in autoimmune diseases. Deficiency of vitamin D is an environmental risk factor ofMS. In this study, we induced tolerogenicDCs by 1,25‐dihydroxyvitamin D3and transferred the tolerogenicDCs (VD3‐DCs) intoEAEmice by adoptive transfer. We found thatVD3‐DCs inhibited the infiltrations of T helper type 1 (Th1) and Th17 cells into spinal cord and increased the proportions of regulatory T cells (CD4+CD25+Foxp3+),CD4+IL‐10+T cells and regulatory B cells (CD19+CD5+CD1d+) in peripheral immune organs, which resulted in attenuatedEAE. However, the proportions of T helper type 1 (Th1) and Th17 cells in spleen and lymph nodes and the levels of pro‐inflammatory cytokines and IgG in serum also increased after transfer ofVD3‐DCs. We conclude that transfer ofVD3‐DCs suppressedEAEby increasing proportions of regulatory T cells,CD4+IL‐10+T cells and regulatory B cells in spleen and reducing infiltration of Th1 and Th17 cells into spinal cord, which suggests a possible immunotherapy method usingVD3‐DCs inMS.