Abstract: A?N3pE-42 is a ? amyloid protein that accumulates specifically as a major constituent of senile plaque in the brains of both sporadic and familial Alzheimer's disease patients. The invention provides antibodies that specifically recognize A?N3pE-42 and can be expected to have a strong ? amyloid-removing action. Particularly, humanized antibodies against A?N3pE-42 are useful to treat human neurodegenerative diseases. Further, since A?N3pE-42 is localized in the brain, the antibodies of the invention can avoid side effects such as kidney disorders caused by the formation of antigen-antibody complex in the blood. An agent for gene therapy using a vector in which a cDNA encoding a protein comprises the antigen-binding region of the antibody can be an efficient therapeutic drug for removing ? amyloid from the brain.