(1262-C) Development and characterization of a novel monoclonal antibody to Tau p217 in Alzheimer’s disease murine models and human disease tissue
Tuesday, February 6, 2024
12:00 PM – 1:00 PM EST
Location: Exhibit Halls AB
Abstract: Phosphorylated tau have emerged as potential fluid-based biomarkers for Alzheimer’s disease (AD) (1). Establishing a fluid-based biomarker, which measures analytes from patient cerebrospinal fluid (CSF) or plasma that associates with disease, would accelerate clinical research in treating this devastating neurodegenerative disease. Tau is phosphorylated at multiple sites. Amongst several specific tau phosphorylation sites, phosphorylation at threonine 217 (pTau217) has recently emerged as a potential reliable biomarker as levels of pTau217 increase in autosomal dominant AD patients (2) and may discriminate AD patients from non-AD patients compared to other tau phosphorylation sites (3,4). Measurement of fluid-based biomarkers largely leverage immuno-based technologies, which include enzyme-linked immunosorbent assay (ELISA) assays, immunoassays with electrochemiluminescence detection (ECL), single molecule arrays, and immunoprecipitation mass spectrometry (IP-MS). These assays require antibodies to the target protein of the highest specificity and sensitivity. To improve on these assays, we sought to develop a rabbit monoclonal antibody to pTau217. Screening of rabbit monoclonal antibody libraries identified a clone, E9Y4S, that exhibited properties specific to pTau217. By western, we detected bands consistent with tau from WT mice that were absent in lambda phosphatase-treated tissue as well as tau KO brain lysates. The E9Y4S clone also specifically detected phosphorylated tau 217 peptide without reactivity to the corresponding non-phosphorylated tau. Using the E9Y4S clone, we developed a sandwich ELISA-compatible antibody pair and plate assay that detected pTau217 in rodent brain tissue. Moreover, we were able to detect elevated p217 levels in human AD brain tissue compared to non-diseased controls. Finally, we used the pTau217 ELISA to detect elevated levels of pTau217 in plasma from the TauP301S transgenic mouse model compared to WT controls, suggesting that our identified pTau217 ELISA pair and assay could be used to detect pTau217 in biofluids. Together, our data suggest the newly identified E9Y4S pTau217 monoclonal rabbit antibody is highly specific and sensitive to pTau217 in human and rodent AD tissue as well as rodent AD biofluids.
[1] Hansson, O. (2021). Nat Med, 27, 954-963. [2] Barthélemy, N.R. et al. (2020). Nat Med, 26, 398-407. [3] Karikari, T.K. et al. (2021). Alzheimers Dement, 17, 755-767. [4] Palmqvist, S. et al. (2020). JAMA, 324, 772-781.