MAPT and Alzheimer disease: As shown in Fig. 1b, both extracellular tau species dramatically decreased in a time-dependent manner after incubation with microglia, with ≤20% total tau and ≤5% phosphorylated tau at Ser202/Thr205 (detected by AT8, a monoclonal antibody recognizing AD-related phosphorylation at Ser202/Thr205 on tau protein) remaining in the media (p < 0.001) after incubation for 48 hrs (Fig. 1b).