Identification of binding sites for anti-aquaporin 4 antibodies in patients with neuromyelitis optica.
OBJECTIVE
Anti-aquaporin 4 antibodies (AQP4-Ab) are specifically detected in patients with neuromyelitis optica. To investigate the role of AQP4-Ab, we examined the antibody binding epitope using human and mouse mutant AQP4.


METHODS
We constructed human and mouse amino acid substitution AQP4 mutants and compared the reactivity with wild-form of human, mouse and rat AQP4.


RESULTS
The decreased intensity of AQP4-Ab staining with mouse AQP4 was recovered to that of human AQP4 with the mouse mutant A228E for 9 of the 10 sera.


CONCLUSIONS
The third extracellular loop of AQP4 is considered to be the major epitope for AQP4-Ab in NMO.
Tani
T
T
Department of Neurology, Brain Research Institute, Niigata University, Japan.
Sakimura
K
K
Tsujita
M
M
Nakada
T
T
Tanaka
M
M
Nishizawa
M
M
Tanaka
K
K
D000595:Amino Acid Sequence; D000818:Animals; D051401:Aquaporin 4 / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D001323:Autoantibodies / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D001666:Binding Sites, Antibody / Q000235:genetics / Q000276:immunology*; D000939:Epitopes / Q000276:immunology; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008969:Molecular Sequence Data; D009471:Neuromyelitis Optica / Q000276:immunology*; D051381:Rats; D014162:Transfection
D051401:Aquaporin 4; D001323:Autoantibodies; D000939:Epitopes