Time course analysis of distribution of PrPres plaques in brain after microinjection of RML scrapie. Panels a-e show detection of PrPres by Mab D13 in coronal sections of whole brain at the level of the needle track. (a) 40 dpi, PrPres plaques in needle track area of cortex are circled. (b) 81 dpi, several groups of plaques in cortex, striatum and adjacent subependymal area are circled. (c) 160 dpi, a larger area of PrPres staining can be seen in needle track region and neighboring areas from meningeal surface to striatum. Several groups of more isolated plaques can also be seen in adjacent areas. One plaque (arrow) is seen in cortex on contralateral side. (d) 213 dpi, numerous plaques are seen on both sides of brain, more in dorsal areas. Some streaked plaque staining can also be seen in the corpus callosum at higher magnification (arrowheads). (e) 320 dpi, plaques are found in most regions, but fewer plaques are seen in central ventral areas and in ventral cortex on contralateral side. At higher magnification streaming plaques in the corpus callosum can also be seen (arrowheads). (f) High power view of single perivascular plaque in cortex at 40 dpi from same mouse as panel a. Central blood vessel is shown by arrow. (g) Group of subependymal plaques (arrows) from same mouse as shown in panel b. (h) Single plaque with prominent vessel (arrow) at interface of corpus callosum and striatum at 81 dpi. (i) PrPres in corpus callosum associated with blood vessels (arrows) which are near to PrPres apparently streaming along interaxonal spaces (arrowheads). (j) Large plaque and adjacent small plaques in cortex with higher density of PrPres surrounding blood vessels (arrows). Scale bars are as follows: f, h, i, j = 50 μm; g = 100 μm.