Amyloid Precursor Protein (APP) is a transmembrane protein and a constituent of neurofibrillary tangles and senile plaques as seen in Alzheimer’s disease. This antibody does not react with APP-like proteins but reacts with deposited APP isoforms in late-stage neurofibrillary tangle-bearing neurons, neuritic processes surrounding senile plaques and neurophil threads in grey matter of Alzheimer’s disease brain.