Th17 cells in autoimmune inflammation and demyelination in the central nervous system

Multiple sclerosis (MS) is a T cell mediated autoimmune disease of the central nervous system (CNS). While the autoantigen, against which the T cell response is directed, is still elusive, much progress has been made in understanding the cytokine phenotype of pathogenic T cells in MS. Previously, IFN-γ producing Th1 cells were considered to be initiating inflammatory demyelination in the CNS of MS patients. More recently, the newly discovered subset of Th17 cells has been identified to possess unique pathogenic properties in CNS autoimmunity. Here, we will discuss basic aspects of Th17 cell biology including Th17 cell differentiation, longevity, and plasticity but also put the generation of Th17 cells in vivo in context with the gut microbiome and elaborate on the function of Th17 cells in experimental autoimmune encephalomyelitis and human MS. Finally, we will highlight specific molecules in Th17 cells as potential therapeutic targets for the treatment of autoimmunity and chronic inflammation.