AQP4 and neuromyelitis optica: Despite the encephalitogenic potential of AQP4(201–220)‐specific T cells, NMO‐like lesions in the CNS, which are characterized by perivascular loss of AQP4 immunoreactivity, are only induced in the presence of AQP4(201–220)‐specific T cells and anti‐AQP4 antibodies but not by AQP4(201–220)‐specific T cells alone.