MAPT and Alzheimer disease: AD brain extract (final concentration = 2 μg total protein/well diluted in OptiMEM) was pre-incubated with either 1% lipofectamine (positive aggregation control), anti-TauC3 antibody, anti-total human tau antibody HT7 (ThermoScientific), or PBS diluted in sterile OptiMEM at 37°C for 20 min.