Abstract: Disclosed is a method for the treatment of a neurodegenerative disorder by isolating a plurality of monocytic cells and introducing a vector containing a gene that expresses a protease capable of degrading amyloid peptide into the isolated monocytic cells. The modified cells are then administered to the patient. Preferably the introduced gene is selected from the group consisting of neprilysin, insulin degrading enzyme and endothelin converting enzyme. The protease capable of degrading amyloid peptide is secreted from the monocytic cells into the extracellular space thereof. According to one variant, the gene that expresses a protease capable of degrading amyloid peptide is the NEP gene with a deletion in the membrane binding domain and/or an appended signal peptide to drive secretion of the modified gene product. This invention contemplates the use of heterologous and autologos (the monocytic cells are obtained from the patient) transplants.