Deletion of indoleamine 2,3 dioxygenase (Ido)1 but not Ido2 exacerbates disease symptoms of MOG-induced experimental autoimmune encephalomyelitis.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) with pathological features of inflammation, demyelination, and neurodegeneration. Several lines of evidence suggest that the enzymes indoleamine 2,3-dioxygenase (Ido)1 and/or Ido2 influences susceptibility to autoimmune diseases. Deletion of exacerbates experimental autoimmune encephalomyelitis (EAE) an animal model of MS. However, no data exist on the role of in the pathogenesis of EAE. We investigated whether deletion of affected the pathogenesis of EAE. Temporal expression of interferon gamma (), variants, variants, as well as genes encoding enzymes of the kynurenine pathway in the spleen and spinal cord of C57BL/6 mice with or without EAE were determined by RT-qPCR. Moreover, EAE was induced in C57BL/6, two knockout strains (Ido1 and Ido1) and one Ido2 knockout mouse strain (Ido2) and disease monitored by clinical scores and weight change. Performance on the rotarod was performed on days 0, 5, 10 and 15 post induction. The extent of demyelination in the spinal cord was determined after staining with Oil red O. The development of EAE altered gene expression in both the spleen and spinal cord. Deletion of exacerbated the clinical symptoms of EAE. In stark contrast, EAE in Ido2 mice did not differ clinically or histologically from control mice. These results confirm a protective role for , on the pathogenesis of MOG-induced EAE in C57BL/6J mice.