Detection of PrPres by D13 staining in non-transgenic C57 mice at various times after microinjection of RML scrapie in striatum. (a) At 40 dpi punctate PrPres staining can be seen in needle track in striatum associated with larger cells (black arrowhead) and in horizontally running axonal areas of corpus callosum at top of panel (arrow). Although blood vessels can be easily seen, there is minimal association of PrPres with blood vessels (green arrowhead). At 80 dpi (b) and 150 dpi (c) PrPres associated with needle track remains punctate and diffuse. (d) At 40 dpi in lateral cortex on ipsilateral side, there is faint PrPres staining (arrow) near outer surface of cortex. (e) At 80 dpi in contralateral cortex, prominent accumulation of diffuse and punctate PrPres (arrow) can be seen associated with parenchymal cells. (f) At the clinical disease end-point,150 dpi, diffuse and punctate PrPres occupies most of cortex. There is no obvious blood vessel association. NT: Needle track, CTX: Cortex. Scale is same in each panel, and bar shown in (a) represents 100 μm.