Seed-dependent propagation of tau pathology and accumulation of endogenous mouse tau. (A) Immunohistochemical staining using isoform-specific antibodies for 3R and 4R tau. Sections of the injected AD (3R/4R tauopathy), CBD (4R tauopathy) and PiD (3R tauopathy) mice are shown. Top panels were stained with 3R-tau-specific antibody and bottom panels, with 4R-tau-specific antibody. The sections were counterstained with haematoxylin solution. The scale bar in AD (3R/4R) with 3R-tau-specific antibody applies to all photomicrographs (200 μm). (B) Immunohistochemical staining using species-specific antibodies for human and murine tau. Top panels were stained with human tau-specific antibody and lower panels, with murine tau-specific antibody. The sections were counterstained with Kernechtrot stain solution. The scale bar in AD/Hu applies to all photomicrographs (100 μm). Hu = human; Mo = mouse.