title: Intravenous immunglobulin binds beta amyloid and modifies its aggregation, neurotoxicity and microglial phagocytosis in vitro.
abstract: Intravenous Immunoglobulin (IVIG) has been proposed as a potential therapeutic for Alzheimer's disease (AD) and its efficacy is currently being tested in mild-to-moderate AD. Earlier studies reported the presence of anti-amyloid beta (Aβ) antibodies in IVIG. These observations led to clinical studies investigating the potential role of IVIG as a therapeutic agent in AD. Also, IVIG is known to mediate beneficial effects in chronic inflammatory and autoimmune conditions by interfering with various pathological processes. Therefore, we investigated the effects of IVIG and purified polyclonal Aβ-specific antibodies (pAbs-Aβ) on aggregation, toxicity and phagocytosis of Aβ in vitro, thus elucidating some of the potential mechanisms of action of IVIG in AD patients. We report that both IVIG and pAbs-Aβ specifically bound to Aβ and inhibited its aggregation in a dose-dependent manner as measured by Thioflavin T assay. Additionally, IVIG and the purified pAbs-Aβ inhibited Aβ-induced neurotoxicity in the SH-SY5Y human neuroblastoma cell line and prevented Aβ binding to rat primary cortical neurons. Interestingly, IVIG and pAbs-Aβ also increased the number of phagocytosing cells as well as the amount of phagocytosed fibrillar Aβ by BV-2 microglia. Phagocytosis of Aβ depended on receptor-mediated endocytosis and was accompanied by upregulation of CD11b expression. Importantly, we could also show that Privigen dose-dependently reversed Aβ-mediated LTP inhibition in mouse hippocampal slices. Therefore, our in vitro results suggest that IVIG may have an impact on different processes involved in AD pathogenesis, thereby promoting further understanding of the effects of IVIG observed in clinical studies.
authors.affiliation: CSL Behring AG, Bern, Switzerland. susann.cattepoel@cslbehring.com
authors.forename: Susann
authors.initials: S
authors.lastname: Cattepoel
authors.forename: Alexander
authors.initials: A
authors.lastname: Schaub
authors.forename: Miriam
authors.initials: M
authors.lastname: Ender
authors.forename: Annette
authors.initials: A
authors.lastname: Gaida
authors.forename: Alain
authors.initials: A
authors.lastname: Kropf
authors.forename: Ursula
authors.initials: U
authors.lastname: Guggisberg
authors.forename: Marc W
authors.initials: MW
authors.lastname: Nolte
authors.forename: Louis
authors.initials: L
authors.lastname: Fabri
authors.forename: Paul A
authors.initials: PA
authors.lastname: Adlard
authors.forename: David I
authors.initials: DI
authors.lastname: Finkelstein
authors.forename: Reinhard
authors.initials: R
authors.lastname: Bolli
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Miescher
mesh_terms: D016229:Amyloid beta-Peptides / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D039481:CD11b Antigen / Q000378:metabolism; D045744:Cell Line, Tumor; D002846:Chromatography, Affinity; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D051379:Mice; D017628:Microglia / Q000166:cytology* / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D010587:Phagocytosis / Q000502:physiology*
chemical_list: D016229:Amyloid beta-Peptides; D039481:CD11b Antigen; D007136:Immunoglobulins