FIG. 3.
Immunoblot analysis of spleen tissue taken from mice inoculated i.p. with ME7 scrapie at 0 to 1, 10, or 14 days old (d.o.). Samples were treated in the presence (+) or the absence (−) of proteinase K (PK) prior to electrophoresis. (a) At 70 d.p.i, no PK resistant accumulations of PrPSc were detected in the spleens of mice inoculated neonatally, but, at this stage, PrPSc could be detected in the spleens of mice injected at 10 and 14 days old (also at 29 days old [not shown]). (b) PrPSc was detected in the spleens of clinically affected mice inoculated as neonates (left hand panel). PrPSc was undetectable in the spleens of neonatally inoculated, clinically negative mice, except in one which had readily detectable PK-resistant accumulations at 592 d.p.i. (right hand panel). All gels included spleen extracts from a clinically affected mouse inoculated as an adult as a positive control (+con). Lane M contains molecular size markers.