The toxicity of beta-amyloid is attenuated by interaction with its specific human scFv E3 in vitro.

Beta-amyloid (Abeta) has been suggested as a potent neurotoxic agent. The Abeta-targeted immunotherapy aims to clear diffuse amyloid deposits and reverse memory deficits in Alzheimer's disease. We generated a human single chain variable domain antibody fragment (scFv) against Abeta40, termed E3, by screening a phage antibody library. E3 scFv could recognize Abeta in human cerebral cortex. It was able not only to prevent the aggregation of Abeta but also to disrupt the Abeta preexisting fibrils. Moreover, the Abeta toxicity to SK-N-SH cells was attenuated by addition of E3 scFv. Our results indicate that site-directed human scFv might be a potential therapeutic agent for Alzheimer's disease.