Antigen-bound and free ?-amyloid autoantibodies in serum of healthy adults.

ABSTRACT: Physiological ?-amyloid autoantibodies (A?-autoantibodies) are currently investigated as potential diagnostic and therapeutic tools for Alzheimer's disease (AD). In previous studies, their determination in serum and cerebrospinal fluid (CSF) using indirect ELISA has provided controversial results, which may be due to the presence of preformed A? antigen-antibody immune complexes. Based on the epitope specificity of the A?-autoantibodies, recently elucidated in our laboratory, we developed (a) a sandwich ELISA for the determination of circulating A?-IgG immune complexes and (b) an indirect ELISA for the determination of free A?-autoantibodies. This methodology was applied to the analysis of serum samples from healthy individuals within the age range of 18 to 89 years. Neuropsychological examination of the participants in this study indicated non-pathological, age-related cognitive decline, revealed especially by tests of visual memory and executive function, as well as speed-related tasks. The ELISA serum determinations showed significantly higher levels of A?-IgG immune complexes compared to free A?-autoantibodies, while no correlation with age or cognitive performance of the participants was found.

SUBMITTER: Maftei M 

PROVIDER: S-EPMC3433427 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature