Protective anti-inflammatory effects of DHA were reported in clinical studies and animal models of colitis, sepsis, and stroke. In the present study, we investigated the effects of DHA on the function of bone marrow-derived dendritic cells (DC) in CD4+ T cell stimulation and differentiation. Pretreatment of DC with DHA prevented LPS-induced DC maturation, maintaining an immature phenotype characterized by low expression of costimulatory molecules and lack of proinflammatory cytokine production (IL-12p70, IL-6 and IL-23). DHA-treated DC were poor stimulators of antigen-specific T cells in terms of proliferation and Th1/Th17 differentiation. This was associated with an increase in p27(kip1), a cell cycle arresting agent. In contrast, T cells co-cultured with DC-DHA express higher levels of TGFβ and Foxp3, without exhibiting a functional Treg phenotype. In addition, DHA prevents up-regulation of VCAM-1 and ICAM-1 in bEND.3 cells (mouse brain microvascular endothelial cell line). Here we report for the first time a beneficial effect of dietary n-3 fatty acids in experimental autoimmune encephalomyelitis (EAE), a model for human multiple sclerosis. The beneficial effect of DHA in EAE was associated with reduced numbers of IFNγ- and IL-17-producing CD4+ T cells in both spleen and CNS.
- Copyright © 2011 by The American Association of Immunologists, Inc.