Conclusions
Conformation-specific anti-TTR antibodies selectively bind amyloidogenic but not native TTR. These novel antibodies may be therapeutically useful in preventing deposition and promoting clearance of TTR amyloid and in diagnosing TTR amyloidosis.
Methods
Antibody clones were generated by immunizing mice with an antigenic peptide comprising a cryptotope within the TTR sequence and screened for specific binding to non-native TTR conformations, suppression of in vitro TTR fibrillogenesis, promotion of antibody-dependent phagocytic uptake of mis-folded TTR and specific immunolabeling of ATTR amyloidosis patient-derived tissue.
Results
Four identified monoclonal antibodies were characterized. These antibodies selectively bound the target epitope on monomeric and non-native misfolded forms of TTR and strongly suppressed TTR fibril formation in vitro. These antibodies bound fluorescently tagged aggregated TTR, targeting it for phagocytic uptake by macrophage THP-1 cells, and amyloid-positive TTR deposits in heart tissue from patients with ATTR amyloidosis, but did not bind to other types of amyloid deposits or normal tissue. Conclusions: Conformation-specific anti-TTR antibodies selectively bind amyloidogenic but not native TTR. These novel antibodies may be therapeutically useful in preventing deposition and promoting clearance of TTR amyloid and in diagnosing TTR amyloidosis.