Amyloid-beta protein N-terminal epitope (Aβ N-terminal epitope)

The Amyloid-beta (Aβ) N-terminal epitope refers to the amino-terminal sequence of the Aβ peptide, typically encompassing residues 1 through 16, which is generated by the proteolytic cleavage of the amyloid precursor protein (APP) (Miles et al., 2011; DOI: 10.1038/srep00131). This region is highly accessible and serves as a primary target for passive immunotherapy in Alzheimer's disease because it remains exposed across various Aβ species, including soluble oligomers and insoluble fibrils (Sevigny et al., 2016; DOI: 10.1038/nature19323). Monoclonal antibodies such as aducanumab and lecanemab bind to this epitope to facilitate the clearance of amyloid plaques from the brain, primarily through microglial-mediated phagocytosis (van Dyck et al., 2023; DOI: 10.1056/NEJMoa2212948). Some therapies, like donanemab, specifically target post-translationally modified versions of this epitope, such as N-terminal pyroglutamate (pGlu3-Aβ), which is found exclusively in aggregated plaques (Mintun et al., 2021; DOI: 10.1056/NEJMoa2100708). By reducing the accumulation of these toxic aggregates, these therapies aim to slow cognitive decline and preserve neurological function in patients with early-stage Alzheimer's disease. However, targeting the N-terminus is frequently associated with Amyloid-Related Imaging Abnormalities (ARIA), which include brain edema (ARIA-E) and microhemorrhages (ARIA-H), requiring careful clinical monitoring (Sperling et al., 2011; DOI: 10.1016/j.jalz.2011.05.2351).

Other names

Abeta N-terminusAβ1-xAmyloid-beta peptide N-terminal domainN-terminal Amyloid-betaN3pG Amyloid-beta

Monoclonal antibodies bind to the N-terminal epitope of amyloid-beta (Aβ) peptides, which facilitates the clearance of existing amyloid plaques via Fc-receptor-mediated microglial phagocytosis and prevents the further aggregation of soluble Aβ monomers into neurotoxic oligomers and fibrils (Sevigny et al., 2016; DOI: 10.1038/nature19323; van Dyck et al., 2023; DOI: 10.1056/NEJMoa2212948).