To create NMO models for studying the effect of astrocyte activation by AQP4 autoantibodies on myelination, we first purified total IgG from the serum of NMO patients who were seropositive for AQP4-IgG (AQP4-IgG) and from healthy controls (Ctrl-IgG), following our established protocol (16) (Supplemental Figure 1A and Table 1; supplemental material available online with this article; https://doi.org/10.1172/JCI195506DS1). This evidence concerns the gene AQP4 and neuromyelitis optica.