Immunohistochemical localization of PrPSc in neurons of the neocortex in Syrian hamsters inoculated with the Sc237 prion strain. A. A neuron in layer 4 of the neocortex at 42 days postinoculation (dpi) shows the plasma membrane filled with PrPSc. Peroxidase immunohistochemistry with the PrP-specific 3F4 monoclonal antibody. B. Three neurons at 58 dpi show early endosomal, late endosomal, and lysosomal staining for PrPSc (green). Goat polyclonal IgG against Cat D (red) was obtained from Santa Cruz Biosciences. Nuclei are stained blue. See text for explanation. Bars in A represents 10 μm and in B, 5 μm.