For the purpose of finding new strategies in the fight against MS based on the control of the Th17 inflammatory axis, here we report that a single administration of adeno-associated virus (AAV) vectors carrying the coding sequence of soluble IL-23R (sIL-23R) delays the onset of the clinical signs, slows the progress of the disease, and reduces the inflammatory infiltration and demyelination in the CNS in a MOG-induced EAE mouse model. The gene discussed is IL23R; the disease is myeloid sarcoma.