title: Antigen-antibody dissociation in Alzheimer disease: a novel approach to diagnosis.
abstract: With the ever-increasing population of aged individuals at risk of developing Alzheimer's disease (AD), there is an urgent need for a sensitive, specific, non-invasive, and diagnostic standard. The majority of efforts have focused on auto-antibodies against amyloid-beta (Abeta) protein, both as a potential treatment, and a reliable biomarker of AD pathology. Naturally occurring antibodies against Abeta are found in the CSF and plasma of patients with AD as well as healthy control subjects. To date, differences between diseased and control subjects have been highly variable. However, some of the antibody will be in preformed antigen-antibody complexes and the extent and nature of such complexes may provide a potential explanation for the variable results reported in human studies. Thus, measuring total amounts of antigen or antibody following unmasking is critical. Here, using a technique for dissociating antibody-antigen complexes, we found significant differences in serum antibodies to Abeta between AD and aged-matched control subjects. While the current study demonstrates the relevance of measuring total antibody, bound and unbound, against Abeta in AD, this technique may be applicable to diseases such as acquired immune deficiency syndrome and hepatitis B where determination of antigen and antibody levels are important for disease diagnosis and assessing disease progression.
authors.affiliation: Department of Neurology, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Gustaw
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Garrett
authors.forename: Hyoung-Gon
authors.initials: HG
authors.lastname: Lee
authors.forename: Rudy J
authors.initials: RJ
authors.lastname: Castellani
authors.forename: Michael G
authors.initials: MG
authors.lastname: Zagorski
authors.forename: Annamalai
authors.initials: A
authors.lastname: Prakasam
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Siedlak
authors.forename: Xiongwei
authors.initials: X
authors.lastname: Zhu
authors.forename: George
authors.initials: G
authors.lastname: Perry
authors.forename: Robert B
authors.initials: RB
authors.lastname: Petersen
authors.forename: Robert P
authors.initials: RP
authors.lastname: Friedland
authors.forename: Mark A
authors.initials: MA
authors.lastname: Smith
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000175:diagnosis* / Q000276:immunology*; D016229:Amyloid beta-Peptides / Q000032:analysis / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000097:blood* / Q000134:cerebrospinal fluid / Q000302:isolation & purification; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000936:Antigen-Antibody Complex / Q000097:blood / Q000134:cerebrospinal fluid; D000941:Antigens / Q000097:blood / Q000134:cerebrospinal fluid / Q000276:immunology*; D006801:Humans; D007158:Immunologic Techniques; D051379:Mice; D008875:Middle Aged
chemical_list: D016229:Amyloid beta-Peptides; D000906:Antibodies; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000941:Antigens