Figure 1.

Neuropathological characteristics of prion disease within the brains of clinically affected mice. (a) Prion diseases are characterized by the presence of aggregations of abnormally folded, disease-specific prion protein (PrP) in affected tissues (brown). In the brain, as shown here, these accumulations are accompanied by extensive neuronal loss, spongiform change (indicated by vacuolation in panel “(b)”), reactive microglia (Iba1⁺ cells, panel “(c),” brown), and reactive astrocytes expressing high levels of glial fibrillary acidic protein (GFAP, panel “(d),” brown). Sections are counterstained with haematoxylin (blue).