Alzheimer's disease: a monoclonal antibody raised against paired helical filaments.

Paired helical filaments (PHF) were isolated from the cerebral cortex of patients with Alzheimer's disease (AD) by a combination of SDS treatment and density gradient centrifugation according to the method of Ihara et al. (1983). The protein component of the preparation was extracted with formic acid and Balb/c mice were used for immunization. Hybridoma supernatants were screened by immunocytochemical staining, by an ELISA assay, and by immunoblotting of SDS-PAGE, the latter both using the PHF preparation as antigen. One hybridoma which showed a strong reactivity with PHF in both the ELISA assay and immunocytochemistry was then used to produce ascites fluid in Balb/c mice. Antibodies reacted immunocytochemically with neurofibrillary tangles and neurites involved in plaque formation in AD but did not show a cross-reaction to human control brain and rat brain. The results indicate that the antibody which has been raised reacts with an antigen component of PHF.