title: The binding affinity of anti-Aβ1-42 MAb-decorated nanoliposomes to Aβ1-42 peptides in vitro and to amyloid deposits in post-mortem tissue.
abstract: Amyloid β (Aβ) aggregates are considered as possible targets for therapy and/or diagnosis of Alzheimer disease (AD), and nanoparticles functionalized with Aβ-specific ligands are considered promising vehicles for imaging probes and therapeutic agents. Herein, we characterized the binding properties of nanoliposomes decorated with an anti-Aβ monoclonal antibody (Aβ-MAb). The Aβ-MAb was obtained in mice by immunization with Aβ antigen followed by hybridoma fusion. Surface Plasmon Resonance (SPR) studies confirmed the very high affinity of purified Aβ-MAb for both Aβ monomers and fibrils (K(D) = 0.08 and 0.13 nm, respectively). The affinity of the biotinylated Aβ-MAb, used thereafter for liposome decoration, was lower although still in the low nanomolar range (K(D) = 2.1 and 1.6 nm, respectively). Biotin-streptavidin ligation method was used to decorate nanoliposomes with Aβ-MAb, at different densities. IgG-decorated liposomes were generated by the same methodology, as control. Vesicles were monodisperse with mean diameters 124-134 nm and demonstrated good colloidal stability and integrity when incubated with serum proteins. When studied by SPR, Aβ-MAb-liposomes, but not IgG-liposomes, markedly bound to Aβ monomers and fibrils, immobilized on the chip. K(D) values (calculated on Aβ-MAb content) were about 0.5 and 2 nm with liposomes at high and low Aβ-MAb density, respectively. Aβ-MAb-liposome binding to Aβ fibrils was additionally confirmed by ultracentrifugation technique, in which interactions occur in solution under physiological conditions. Moreover, Aβ-MAb-liposomes bound amyloid deposits in post-mortem AD brain samples, confirming the potential of these nanoparticles for the diagnosis and therapy of AD.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Canovi
authors.forename: Eleni
authors.initials: E
authors.lastname: Markoutsa
authors.forename: Adina N
authors.initials: AN
authors.lastname: Lazar
authors.forename: Georgios
authors.initials: G
authors.lastname: Pampalakis
authors.forename: Carla
authors.initials: C
authors.lastname: Clemente
authors.forename: Francesca
authors.initials: F
authors.lastname: Re
authors.forename: Silvia
authors.initials: S
authors.lastname: Sesana
authors.forename: Massimo
authors.initials: M
authors.lastname: Masserini
authors.forename: Mario
authors.initials: M
authors.lastname: Salmona
authors.forename: Charles
authors.initials: C
authors.lastname: Duyckaerts
authors.forename: Orfeu
authors.initials: O
authors.lastname: Flores
authors.forename: Marco
authors.initials: M
authors.lastname: Gobbi
authors.forename: Sophia G
authors.initials: SG
authors.lastname: Antimisiaris
mesh_terms: D000544:Alzheimer Disease / Q000175:diagnosis* / Q000473:pathology; D000682:Amyloid / Q000276:immunology; D016229:Amyloid beta-Peptides / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry / Q000276:immunology*; D000915:Antibody Affinity / Q000276:immunology*; D001710:Biotin / Q000031:analogs & derivatives / Q000737:chemistry; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008081:Liposomes / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D010316:Particle Size; D010446:Peptide Fragments / Q000276:immunology*; D010713:Phosphatidylcholines / Q000737:chemistry; D010714:Phosphatidylethanolamines / Q000737:chemistry; D058225:Plaque, Amyloid / Q000276:immunology* / Q000378:metabolism; D011092:Polyethylene Glycols / Q000737:chemistry; D013194:Staining and Labeling / Q000379:methods; D055672:Static Electricity; D020349:Surface Plasmon Resonance; D014461:Ultracentrifugation
chemical_list: C519184:1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy-poly(ethylene glycol 2000); D000682:Amyloid; D016229:Amyloid beta-Peptides; D000911:Antibodies, Monoclonal; D008081:Liposomes; D010446:Peptide Fragments; D010713:Phosphatidylcholines; D010714:Phosphatidylethanolamines; C075222:amyloid beta-protein (1-42); D011092:Polyethylene Glycols; D001710:Biotin; C010942:1,2-distearoyllecithin