PHF1 and supranuclear palsy, progressive, 1: To identify the specific nature of the tau-positive vesicular structures in PVAs, double immunofluorescence staining was performed on middle frontal sections of immunized and unimmunized PSP cases with antibodies against PHF1 together with early endosome antigen 1(EEA1) as an endocytic marker, microtubule-associated proteins 1A/1B light chain 3B (LC3B) as an autophagosome marker, or lysosomal-associated membrane protein 1 (Lamp1) as a lysosome marker.