I do not know if the positivity is specific. However, in obvious nerve fibre bundles there is clear punctate posivity along each fibre.

Image shows Hippocampal region

Same pattern of positivity to that seen in mouse kidney, under identical conditions.

Cortico-medullary junction.

Not quite sure but, PCT cell membrane positivity ( descending) and also a light positivity in smaller tubules in the immediate medulla.

Cytoplasmic positivity is seen in what appears to be PCT lumenal membranes and supporting cells ( mesangial?) of the glomerulus.

Pituitary ( lower structure) and  hypothalamus above.

After comparing this Ab with Abcam’s anti CD26 Abs, I conclude that CD26 must be positive for not only bile canaliculi ( red arrowheads) but, also lining cells of liver sinusoids ( blue arrowheads) .

I suggest that, if one needs to demonstrate bile canaliculi, one uses an anti CD 10 antibody ( aka CALLA) that I only know from R&D Systems AF2736

Tongue: the muscle itself appears negative but, the associated fibroblasts are strongly positive.

NB: only a subpopulation of fibroblasts are positive, when examining the whole head region.

Developing jaw: chondrocytes ( not chondroblasts) and associated striated muscle show strong positivity