Representative Histology of TgA20 indicator mice.

<p>Selected examples of histological analysis using immunohistochemistry with PrP specific BAR224 Ab (reddish-brown staining, panels A–F) and anti-GFAP antibody staining activated astrocytes (bright red, panels G–L) in hippocampal sections. (<b>A and G</b>) Negative control sections from mice inoculated with SLS-treated NBH exhibited no PrP^Sc staining or spongiosis and limited astrocyte activation. (<b>B and H</b>) Positive control sections from mice inoculated with RML5 revealed diffuse PrP^Sc staining and significant spongiosis and astrogliosis. (<b>C and I</b>) Sections from mice inoculated with SLS-treated TgA20RML resulted in limited PrP^Sc deposits, spongiosis and astrogliosis, while (<b>D and J</b>) sections from mice inoculated with Mte-treated TgA20RML revealed little or no scrapie neuropathology. (<b>E and K</b>) sections from mice inoculated with SLS-treated RML5 resulted in neuropathology similar to sections from TgA20RML treated mice (Band H). (<b>F and L</b>) Hippocampal sections from the only mouse to become ill with Mte treated RML5 showed limited PrP^Sc spongiosis and astrogliosis.