1,25‐dihydroxyvitamin D 3 ‐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 ( DC s), 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 for MS . Administration of tolerogenic DC s has been used as an immunotherapy in autoimmune diseases. Deficiency of vitamin D is an environmental risk factor of MS . In this study, we induced tolerogenic DC s by 1,25‐dihydroxyvitamin D 3 and transferred the tolerogenic DC s ( VD 3 ‐ DC s) into EAE mice by adoptive transfer. We found that VD 3 ‐ DC s inhibited the infiltrations of T helper type 1 (Th1) and Th17 cells into spinal cord and increased the proportions of regulatory T cells ( CD 4 + CD 25 + Foxp3 + ), CD 4 + IL ‐10 + T cells and regulatory B cells ( CD 19 + CD 5 + CD 1d + ) in peripheral immune organs, which resulted in attenuated EAE . 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 of VD 3 ‐ DC s. We conclude that transfer of VD 3 ‐ DC s suppressed EAE by increasing proportions of regulatory T cells, CD 4 + 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 using VD 3 ‐ DC s in MS .