CD8alpha dendritic cells and immune protection from experimental allergic encephalomyelitis.

Dendritic cells (DC) represent a phenotypically heterogeneous population endowed with two important biological functions, immunity and tolerance. Here we report that the injection of splenic CD8alpha(+) DC, derived from rats with experimental allergic encephalomyelitis (EAE), delayed the onset and suppressed the severity of EAE in Lewis rats. This was accompanied by the lack of magnetic resonance imaging (MRI) lesions in the brain and spinal cord and by reduced numbers of inflammatory cells within the central nervous system. Injection of CD8(alpha+) DC inhibited T cell proliferation that may relate to increased interferon (IFN)-gamma and nitric oxide production. Although CD8(+)CD28(-) suppressor T cells, apoptotic cells and co-stimulatory molecules were not altered, CD4(+) T cells expressing interleukin (IL)-10 were augmented in rats receiving CD8alpha(+) DC compared to rats receiving total DC or medium. These results demonstrate that rat splenic CD8alpha(+) DC could provide a cellular basis for a novel, individualized immunotherapy using autologous DC as a complement to conventional therapy in diseases with an autoimmune background such as multiple sclerosis.