DCII:: a novel monoclonal antibody revealing Alzheimer's disease-specific tau epitope

Using tau protein extracts from Alzheimer's disease (AD) brain tissue, we generated a monoclonal antibody (mAb DCII) which decorated neurofibrillary pathology in brain derived from AD patients on immunohistochemistry, and which lacked reactivity with healthy brain tissue. The same pattern of DCII specificity was observed on Western blot. The main constituent of structures decorated by DCII is microtubule-associated protein tau. In Western blot, DCII recognized neither native healthy tau nor its full length recombinant counterpart. However, the mAb showed strong immunoreactivity with truncated tau (residues tau151-421), thus indicating the requirement for a conformational epitope. Importantly, the DCII epitope was phosphorylation independent. The immunochemical parameters of mAb show that DCII could represent a novel structural probe with the specificity for conformation of pathological tau present in AD brains.