Brain-derived tau oligomers were purified by immunoprecipitation as described previously (Lasagna-Reeves et al., 2012). Tau oligomers were isolated by immunoprecipitation with the T22 antibody using PBS-soluble fractions of homogenates prepared from AD brain. These were then purified by fast protein liquid chromatography (FPLC) using PBS (pH 7.4). Additional analyses include Western blots to detect contamination with monomeric tau or large tau aggregates (tau-5, normally appear on top of the stacking gel) and using a mouse anti-IgG to identify non-specific bands. BDTOs were subsequently conjugated to pHrodo-Red per manufacturer’s protocol.
