The difference in immunohistochemical reactivity of monoclonal antibodies against amino-terminal residues of amyloid-β peptide

Immunohistochemistry for amyloid-{beta} (A{beta}) peptide is an indispensable method for Alzheimers disease (AD) research. Despite a wide variety of available antibodies against the peptides, the difference of immunohistochemical reactivity is not fully described among anti-A{beta} antibodies. Immunohistochemical reactivity of Abs against A{beta} peptides is critical for accurate and reliable evaluation of A{beta} burden in patients as well as models of AD. Here, we examined immunohistochemical reactivity of two mouse and one rabbit monoclonal antibodies against A{beta} N-terminal regions using two AD mouse models, AppNL-F and AppNL-G-F. 6E10, 82E1 and D54D2 A{beta} antibodies were used in this study. We found significant differences in the immunohistochemical reactivity in both AppNL-F and AppNL-G-F models. While 6E10 immunoreactivity was mainly localized to A{beta} plaques, D54D2 and 82E1 antibodies stained much more broadly beyond plaques. Interestingly, the latter two Abs showed blurred filamentous immunoreactivity beyond amyloid plaque cores. Double immunostaining using a tyramide signal amplification method, Fluorochromized Tyramide-Glucose Oxidase (FT-GO), suggested that the differential immunohistochemical outcomes were only partially attributable to their sensitivity. Moreover, heat induced epitope retrieval (HIER) did not affect the differential immunohistochemical outcomes. Our analysis indicates that outcomes of A{beta} immunohistochemistry highly depends on the antibody used in the study.