Fig. 7.

Association of PS1 with amyloid plaques and NFTs in AD. Shown are sections of hippocampus from an individual with sporadic AD. A, Double labeling with Ab 231 to PS1 (brown) and the monoclonal antibody β1 to Aβ (red) shows that PS1-positive neurons (arrow) surround amyloid plaques (arrowhead). B, Analysis of a single mature plaque by double label immunofluorescence for PS1 (green) and Aβ (dark blue). Note that PS1 appears in dystrophic neurites, which are labeledgreen for PS1 or light blue from the overlap of PS1 and Aβ. A low level of PS1 immunoreactivity appears in the amyloid core (arrowhead), which is staineddark blue for Aβ. C, Double labeling for phosphorylated tau (dark blue, Ab PHF-1) and the N-terminal epitope of PS1 (green, Ab 231). Two neurons with NFTs (arrows) are labeled for both phosphorylated tau and PS1, but the N-terminal PS1 Ab does not double label NFTs, which are labeled with Ab PHF-1. D, Double labeling for phosphorylated tau (dark blue, Ab PHF-1) and the C-terminal loop region of PS1 (green, Ab R28). Shown is an NFT that is double-labeled (arrow, light blue). An example of a neuron showing predominantly PHF-1 labeling (dark blue) is seen in the bottom right corner.