MAPT and Alzheimer disease: The GW-23B7 used in the in vivo experiments was documented to be > 99% pure intact IgMκ pentamer (Fig. 4a), to react with oligomeric/fibrillar forms of human extracted PHF in immunoblots and detect intra- and extracellular tau pathology in a human AD brain (Fig. 4b), to be cross-reactive with oligomeric forms of Aβ in immunoblots, and to colocalize with material related to amyloid plaques in a human AD brain (Fig. 4c).