An antibody to beta amyloid and the amyloid precursor protein inhibits cell-substratum adhesion in many mammalian cell types.

An epitope-specific antibody directed against the first 16 amino acids of the beta amyloid protein (anti-BP16) immunoprecipitated the secreted form of the amyloid precursor protein (APP) from the conditioned medium of PC12 cells. This antibody caused neurite retraction in differentiated PC12 cells and inhibited cell-substratum adhesion in many neuronal and non-neuronal cell types. The inhibitory effect of anti-BP16 was abolished by preabsorption of the antibody with BP16 peptide. Antibodies directed against other domains of APP did not inhibit cell adhesion. The secreted form of APP may be important for cell adhesion in many different mammalian cell types.