title: Specific uptake of an amyloid-β protofibril-binding antibody-tracer in AβPP transgenic mouse brain.
abstract: Evidence suggests that amyloid-β (Aβ) protofibrils/oligomers are pathogenic agents in Alzheimer's disease (AD). Unfortunately, techniques enabling quantitative estimates of these species in patients or patient samples are still rather limited. Here we describe the in vitro and ex vivo characteristics of a new antibody-based radioactive ligand, [125I]mAb158, which binds to Aβ protofibrils with high affinity. [125I]mAb158 was specifically taken up in brain of transgenic mice expressing amyloid-β protein precursor (AβPP) as shown ex vivo. This was in contrast to [125I]mAb-Ly128 which does not bind to Aβ. The uptake of intraperitoneally-administered [125I]mAb158 into the brain was age- and time-dependent, and saturable in AβPP transgenic mice with modest Aβ deposition. Brain uptake was also found in young AβPP transgenic mice that were devoid of Aβ deposits, suggesting that [125I]mAb158 targets soluble Aβ protofibrils. The radioligand was diffusely located in the parenchyma, sometimes around senile plaques and only occasionally colocalized with cerebral amyloid angiopathy. A refined iodine-124-labeled version of mAb158 with much improved blood-brain barrier passage and a shorter plasma half-life might be useful for PET imaging of Aβ protofibrils.
authors.affiliation: Department of Public Health and Caring Sciences/Geriatrics, Uppsala University, Rudbeck Laboratory, Uppsala, Sweden.
authors.forename: Kristina
authors.initials: K
authors.lastname: Magnusson
authors.forename: Dag
authors.initials: D
authors.lastname: Sehlin
authors.forename: Stina
authors.initials: S
authors.lastname: Syvänen
authors.forename: Marie M
authors.initials: MM
authors.lastname: Svedberg
authors.forename: Ola
authors.initials: O
authors.lastname: Philipson
authors.forename: Linda
authors.initials: L
authors.lastname: Söderberg
authors.forename: Karin
authors.initials: K
authors.lastname: Tegerstedt
authors.forename: Mats
authors.initials: M
authors.lastname: Holmquist
authors.forename: Pär
authors.initials: P
authors.lastname: Gellerfors
authors.forename: Vladimir
authors.initials: V
authors.lastname: Tolmachev
authors.forename: Gunnar
authors.initials: G
authors.lastname: Antoni
authors.forename: Lars
authors.initials: L
authors.lastname: Lannfelt
authors.forename: Håkan
authors.initials: H
authors.lastname: Hall
authors.forename: Lars N G
authors.initials: LN
authors.lastname: Nilsson
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D000682:Amyloid / Q000276:immunology / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001921:Brain / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007457:Iodine Radioisotopes / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011485:Protein Binding / Q000276:immunology
chemical_list: D000682:Amyloid; D016564:Amyloid beta-Protein Precursor; D000911:Antibodies, Monoclonal; D007457:Iodine Radioisotopes