Both serum NMO-IgG and CSF-derived AQP4-specific monoclonal recombinant antibodies recapitulate NMO pathology when microinjected into the CNS, added to ex vivo spinal cord slices in the presence of human complement proteins [13], introduced into rodent models of CNS inflammation [12, 14], or injected into mice pretreated with Freund’s complete adjuvant [15]. The gene discussed is AQP4; the disease is neuromyelitis optica.