Experimental autoimmune encephalomyelitis is the prototypic T cell-mediated autoimmune disease model. Classically, this disease was viewed in terms of type 1 versus type 2 immunity: the type 1 cytokines IFNgamma and TNFalpha promoting disease, whereas an IL-4-dominated, type 2 response was protective. However, studies in knockout mice do not support this paradigm. More recent data point to important roles for IL-23 and IL-17 (rather than IL-12 and IFNgamma) in the establishment and persistence of the inflammatory lesion. IL-10 appears to be the dominant cytokine mediating recovery. The source of IL-10 includes B cells (most probably in the peripheral lymphoid organs). However, the key IL-10-producing cell within the central nervous system is a CD4+CD25+ T cell population that has regulatory function and is critical to resolution of the disease.