Identification of peptide targets in neuromyelitis optica.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease that predominantly affects the optic nerves and spinal cord. Recombinant antibodies (rAbs) generated from clonally expanded plasma cells in an NMO patient are specific to AQP4 and pathogenic. We screened phage-displayed peptide libraries with these rAbs, and identified 14 high affinity linear and conformational peptides. The linear peptides shared sequence homologies with NMO autoantigen AQP4 on the extracellular surface. Competitive inhibition ELISA and immunocytochemistry demonstrated that these peptides represent epitopes of NMO autoantigen AQP4. Peptide epitopes/mimotopes may have potential uses for disease prognosis, monitoring, and therapy.