Repetitive Immunization Enhances the Susceptibility of Mice to Peripherally Administered Prions
Figure 5
Brain pathology of terminally sick or asymptomatic mice.
Immunized (i) and non-immunized mice (ni) inoculated intracerebrally (i.c.) or intraperitoneally (i.p.) with medium or high dose of prions were analyzed by histology. HE stains and immunohistochemistry were performed as indicated: astrocytes (GFAP), microglia (Iba1), PrP deposits (SAF84), showing astrogliosis, microglia activation, and prion protein deposition in terminally sick mice from each of the experimental groups. Histoblot analyses detected PrPSc in the brains of all terminally sick mice with similar distribution patterns. Non-immunized mice inoculated i.p. with a medium dose of prions remained healthy up to 500 dpi, and displayed much less GFAP+ astrocytes and Iba1+ microglia cells, and lacked both PrP deposits (SAF84) and PrPSc (histoblot) at 400 dpi. Scale bars: histoblot = 1 mm; histology = 100 µm.