Comparison of PrP^Sc deposition between different sheep genotypes and inocula.

PrP^Sc deposition in brain regions varies with sheep PRNP genotype and source of inoculum. Sheep inoculated with the WTD scrapie agent from cerebrum (sheep 1 (A-C), sheep 2 (D-F), sheep 3 (G-I), and sheep 4 (J-L)) are compared to a sheep inoculated with WTD scrapie agent from the obex (sheep 6 (M-O)). A VRQ/VRQ sheep inoculated with the WTD scrapie agent from cerebrum had intense widespread immunoreactivity in the brainstem at the level of the obex (A, D), cerebellum (B, E), and neocortex (C, F). An ARQ/ARQ sheep inoculated with the WTD scrapie agent from cerebrum had less intense but widespread accumulation in the obex (G), cerebellum (H), and neocortex (I). Representative brain regions of sheep 4 that was negative by EIA and WB lacks immunoreactivity (J-L). A VRQ/VRQ sheep inoculated with the WTD scrapie agent from obex (sheep 6) had mild PrP^Sc accumulation in the obex (M), cerebellum (N), and neocortex (O).