Generation and characterization of novel conformation-specific monoclonal antibodies for α-synuclein pathology

alpha-Synuclein (alpha-syn), a small protein that has the intrinsic propensity to aggregate, is implicated in several neurodegenerative diseases including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), which are collectively known as synudeinopathies. Genetic, pathological, biochemical, and animal modeling studies provided compelling evidence that alpha-syn aggregation plays a key role in the pathogenesis of PD and related synudeinopathies. It is therefore of utmost importance to develop reliable tools that can detect the aggregated forms of alpha-syn. We describe here the generation and characterization of six novel conformation-specific monoclonal antibodies that recognize specifically alpha-syn aggregates but not the soluble, monomeric form of the protein. The antibodies described herein did not recognize monomers or fibrils generated from other amyloidogenic proteins including beta-syn, gamma-syn, beta-amyloid, tau protein, islet amyloid polypeptide and ABri. Interestingly, the antibodies did not react to overlapping linear peptides spanning the entire sequence of alpha-syn, confirming further that they only detect alpha-syn aggregates. In immunohistochemical studies, the new conformation-specific monoclonal antibodies showed underappreciated small micro-aggregates and very thin neurites in PD and DLB cases that were not observed with generic pan antibodies that recognize linear epitope. Furthermore, employing one of our conformation-specific antibodies in a sandwich based ELISA, we observed an increase in levels of alpha-syn oligomers in brain lysates from DLB compared to Alzheimer's disease and control samples. Therefore, the conformation-specific antibodies portrayed herein represent useful tools for research, biomarkers development diagnosis and even immunotherapy for PD and related pathologies. (C) 2015 Elsevier Inc All rights reserved.