Diagnostic drug and diagnostic method for alzheimer's disease

Abstract

The present invention provides an agent for determining Alzheimer's disease, comprising an anti-S38AA antibody, a method of determining Alzheimer's disease in a test animal, comprising detecting an S38AA fragment in a sample collected from said animal, and a method of screening for a substance that treats or prevents Alzheimer's disease, comprising contacting a test substance with a cell permitting measurement of production of a S38AA fragment, measuring the production amount of the S38AA fragment in the cell, and comparing the production amount with that of the S38AA fragment in a control cell free of contact with the test substance, and selecting a test substance that down-regulates the production amount of the S38AA fragment as a substance capable of treating or preventing Alzheimer's disease, based on the comparison results.

1 . A method of detecting an S38AA fragment in a test person affected with Alzheimer's disease or having a high possibility of being affected with Alzheimer's disease in the near future, said method comprising:
 (1) collecting a sample from the test person; and   (2) detecting whether an S38AA fragment is present in the sample by contacting the sample with an anti-S38AA antibody and detecting binding between S38AA fragment and anti-S38AA antibody complex,   wherein the S38AA is a polypeptide comprising the amino acid sequence shown by SEQ ID NO: 2,   wherein the S38AA fragment is a polypeptide consisting of an S38AA extra-membranous domain or a partial polypeptide thereof,   wherein the antibody is an antibody specifically recognizing an amino acid region selected from the following (a) to (c): (a) the 689-1119th amino acids of the amino acid sequence shown by SEQ ID NO: 2, (b) the 399-688th amino acids of the amino acid sequence shown by SEQ ID NO: 2, and (c) an amino acid region spanning both regions (a) and (b), and   wherein the sample collected from the test person is blood or cerebrospinal fluid.   
     
     
         2 . The method of  claim 1 , wherein the sample collected from the test person is blood. 
     
     
         3 . The method of  claim 1 , wherein the sample collected from the test person is plasma.