The results of using fly models to investigate passive immunotherapy to block amyloid-²42 peptides of amyloid plaques that damage the brain cells of patients with Alzheimer's disease (AD) are now presented by researchers. The scientists are investigating passive immunotherapy, one of the most promising approaches to blocking the amyloid-β42 (Aβ42) peptide, the main component of the amyloid plaques that damage the brain cells of patients with AD.