– Repulsive guidance molecule (RGM) is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein that has diverse functions in the developing and pathological central nervous system (CNS). The binding of RGM to its receptor neogenin regulates axon guidance, neuronal differentiation, and survival during the development of the CNS. RGMa induces T cell activation in experimental autoimmune encephalomyelitis (EAE), which is the animal model of multiple sclerosis (MS).