Characterisation of an antibody relevant to the neuropathology of Alzheimer disease.

The specificity of BR88, a polyclonal antibody we raised against amino acids 1-12 of beta/A4 (beta-amyloid protein), has been reexamined in view of a claim made that it cross-reacts with tau-protein, probably the sole component of the paired helical filaments of Alzheimer disease. We have used enzyme-linked immunosorbent assays, immunoblots, and immunohistochemistry, together with appropriate controls, to show that BR88 does not cross-react with tau. This contradicts the claim in question and confirms our previous findings in which BR88 was used to show that some tangle-bearing cells displayed the N-terminus of beta/A4 on their surfaces. The conclusions formed in that earlier work therefore remain intact.