Macrophages are intensely positive. I am not sure if the moderate positivity is specific/non-specific (  due to primary antibody requiring further dilution).

Bergmann /radial glia in cerebellum appear to be positive.

NB: if this was endogenous biotin, I would expect a less intense punctate positivity ( no endogenous biotin blocking, however).

Mea culpa

Ependymal cells are positive: lateral ventricle ( corpus callosum is seen on the Right-hand side).

Positivity appears to be confined to blood vessel endothelium

I am not familiar with this protein but, HPA images show an identical distribution pattern.

Sequential sections of a TASTPM mouse brain

Upper image of section pretreated with  Formic acid AR.

Lower image of section pretreated using Citric acid HIER.

Note that Formic acid exposes only extracellular plaque amyloid beta.

Citric acid HIER also exposes plaque amyoid but, additionally exposes intracellular amyloid or….is this APP?

Not shown but, in wt mouse brain, I see intracellular neuronal positivity with this ab, only after Citric acid HIER.

Thus this must be APP?

Diffuse positivity of the neuropil ( negative nerve tracts) of the striatum.