For many years CD4+ T cells have been considered an important cell type involved in MS pathogenesis due to early observations in experimental autoimmune encephalomyelitis (EAE) – the animal model for MS – that CNS demyelinating disease can be transferred by adoptive transfer of myelin-reactive CD4+ T cells (31, 32), and further evidenced by the observation that EAE cannot be transferred by antibodies alone. The gene discussed is CD4; the disease is demyelinating disease.