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Cells with a familial Alzheimer's disease mutation produce authentic beta-peptide.

Cells overexpressing the beta-amyloid precursor protein possessing a mutation found in familial Alzheimer's disease overproduce beta-amyloid peptide (A beta). Because these findings were based on immunological identification, we have chemically characterized the peptides produced. Purified A beta fragments from the conditioned media of these cells were found to have N-terminal sequence consistent with the A beta found in cerebral plaques. Mass spectrometric data demonstrated a series of A beta fragments consistent with those found in Alzheimer's disease (AD); the major species corresponding to A beta(1-40). Significantly, a longer fragment corresponding to A beta(1-42) was found. These findings suggest that this cellular system may be useful for mechanistic studies of A beta generation and possibly for the development of therapeutic agents to treat AD.