This is a humanized IgG1 antibody using the same sequences as the therapeutic antibody donanemab. It recognizes Aβ(p3-42), a pyroglutamate form of Aβ that is aggregated in amyloid plaques. Aβ precursor protein (APP) functions as a cell surface receptor and performs physiological functions on the surface of neurons relevant to neurite growth, neuronal adhesion and axonogenesis. Interaction between APP molecules on neighboring cells promotes synaptogenesis. The rationale behind donanemab is that targeting deposited plaque itself is necessary to clear existing amyloid burden from the brain, rather than merely prevent deposition of new plaques or growth of existing plaques.