Figure 1

In vitro formation of tau APFs. Tau oligomers used to prepare tau APFs were characterized by EM (a) and AFM (b). Tau APFs were also imaged by EM (c) and AFM (d). Tau APFs were recognized by the αAPF antibody on dot blot, which did not recognize recombinant tau monomers, oligomers, or fibrils. Tau oligomers were recognized by T22, and all tau species were detected by Tau-5 (e). A distinct peak near 670 nm on HPLC revealed that tau APFs are formed by 10–12 tau monomers (f). The scale bars for a and b correspond to 100 nm, for c 20 nm, and for d 40 nm. White arrowheads indicate tau APF formation.