Persistence of Aβ seeds in APP null mouse brain

Cerebral beta-amyloidosis is induced by inoculation of A beta seeds into APP transgenic mice, but not into App(-/-) (APP null) mice. We found that brain extracts from APP null mice that had been inoculated with All seeds up to 6 months previously still induced beta-amyloidosis in APP transgenic hosts following secondary transmission. Thus, A beta seeds can persist in the brain for months, and they regain propagative and pathogenic activity in the presence of host A beta.