Modulation of amyloid precursor protein processing by compounds with various mechanisms of action: detection by liquid phase electrochemiluminescent system.

beta-Amyloid peptide (A beta) is a major component of senile plaques formed in the brain of Alzheimer disease patients. We describe here a new method of quantitating A beta in biological material using liquid phase electrochemiluminescent system (LPECL). We used both enzyme-linked immunosorbent assay (ELISA) and LPECL methods to measure A beta and APPs alpha levels in conditioned medium of beta-amyloid precursor protein (APP)-transfected CHO cells treated with known modulators of APP processing, and in CSF and plasma of guinea pigs. Our results indicate that while maintaining the accuracy and sensitivity of ELISA, LPECL is a significantly taster and less labor-intensive method for measuring of A beta and APPs alpha levels in biological fluids.