AFFITOPE-induced antibodies detect amyloid deposits but spare neuronal APP on murine and human brain sections.

<p>Sections prepared from the hippocampus (A, D, G, J, K, M) and the cortex (B, E, H), of a 12 month old Tg2576 mouse were incubated with plasma of AD01- (D, J) or AD02-treated mice (E, K) and, for control purposes, with the antibodies 6E10 (A+B) and mAb 22C11 (J, K, M), recognizing Aß and full length APP. G) and H) show a loss of immunoreactivity on Tg2576 brain sections incubated with AD01- and AD02-induced samples which were mixed with the respective AFFITOPE peptide to inhibit AFFITOPE specific staining (i.e. G: AD01-induced plasma + 10µM AD01 peptide, H: AD02-induced plasma + 10µM AD02 peptide). Sections prepared from the cortex of a female AD patient (C, F, I, L Braak stage VI,) were incubated with the Aß specific control antibody BAM10 (C), AD01- (F) and AD02-induced plasma (I) or plasma from naïve control mice as negative control (L). Binding of the Abs was detected using a standard DAB immuno-histochemistry protocol. The analysis of human sections reveals a specific amyloid deposit staining of AD01-(F) and AD02-induced Abs (I) present in murine plasma similar to staining obtained by using control antibody BAM10 (C), whereas no staining was detectable with plasma derived from a naïve, untreated animal (L). Pictures were taken at a magnification of 20x. Scale bars: 200µm; circles in G and H indicate amyloid deposits devoid of amyloid specific staining by AD01- or AD02- induced antibodies following peptide-specific competition.