Figure 6.

Blocking of PrP^RES immunoreactivity by target peptide before incubation. All tissues were obtained from a terminally ill, PLP-perfused, i.p. inoculated Tg[CerPrP] mouse sacrificed at 233 dpi. Tissues were immunostained using an IHC protocol incorporating the BAR-224 monoclonal antibody, amplification using TSA reagents and a peptide blocking step. Top row (no blocking): PrP^RES immunoreactivity (red) in (A) brainstem neuropil, (B) splenic nucleated cells, (C) pancreatic islet epithelial cells, and (D) hepatic Kupffer cells. Bottom row (blocking): Pre-application incubation of the primary antibody with its eliciting peptide results in complete to near-complete abrogation of PrP^RES immunoreactivity in matched tissue sections (E–H). Scale bars: 100 μm (A and E); 100 μm (B and F); 80 μm (C and G); 27.5 μm (D and H).