Fig. 5. Detection of amyloid-ß peptide during endocytosis by ELISA. H4 cells transiently transfected with various APP constructs were pulse-labeled with biotinylated-6E10 and chased for the indicated time points in the absence or presence of DAPT for 4 hours. The conditioned media was collected and the biotinylated-6E10-labeled amyloid-ß peptide was measured by ELISA using BA27 as the capture antibody and streptavidin-HRP for detecting labeled 6E10. (A) The time-course of amyloid-ß detected from the conditioned media of wild-type APP770 and APP770sw-transfected H4 cells is illustrated. Data shown are typical of 3 separate experiments. (B) Comparison of the amyloid-ß levels detected from various conditions (wt, Swedish, delta49, DAPT) for the first 30 minutes. A significant difference (P<0.001) in the amount of amyloid-ß levels compared to that of the wild-type is shown by asterisk.