Development and Characterization of Mouse-Specific Anti-Tau Monoclonal Antibodies: Relevance for Analysis of Murine Tau in Cerebrospinal Fluid

Background: Clearance of tau seeds by immunization with tau antibodies is currently evaluated as therapeutic strategy to block the spreading of tau pathology in Alzheimer's disease and other tauopathies. Preclinical evaluation of passive immunotherapy is performed in different cellular culture systems and in wild-type and human tau transgenic mouse models. Depending on the preclinical model used, tau seeds or induced aggregates can either be of mouse, human or mixed origin. Objective: We aimed to develop human and mouse tau-specific antibodies to discriminate between the endogenous tau and the introduced form in preclinical models. Methods: Using hybridoma technology, we developed human and mouse tau-specific antibodies that were then used to develop several assays to specifically detect mouse tau. Results: Four antibodies, mTau3, mTau5, mTau8, and mTau9, with a high degree of specificity for mouse tau were identified. Additionally, their potential application in highly sensitive immunoassays to measure tau in mouse brain homogenate and cerebrospinal fluid is illustrated, as well as their application for specific endogenous mouse tau aggregation detection. Conclusion: The antibodies reported here can be very important tools to better interpret the results obtained from different model systems as well as to study the role of endogenous tau in tau aggregation and pathology observed in the diverse mouse models available.