Profiling of amyloid beta peptide variants using SELDI Protein Chip arrays

The profile of amyloid beta (A beta) peptide variants secreted into the media of human cultured cells that express the amyloid precursor protein was examined by Surface Enhanced Laser Desorption/Ionization (SELDI) ProteinChip technology from Ciphergen Biosystems using biologically active ProteinChip Arrays. An anti-A beta polyclonal antibody (anti-NTA4) was used to capture and purify multiple immunoreactive A beta fragments from a single microliter of media onto the ProteinChip Array. Fragments retained on the surface of the ProteinChip Array were detected directly by mass in the ProteinChip System to provide detailed information on the identity of different A beta variants secreted from the cultured cells. We discuss existing and potential applications of this immunoassay for the detection and relative quantitation of A beta species from both cultured cell systems and clinical samples.