Not a “punchy” ab, under my conditions.

This can be improved by using more sensitive detection methods ( sometimes) eg: enhanced DAB ( homemade or bought in); using IF instead to increase apparent S:N; using polymer- HRP conjugated  secondaries….most often needing the enhanced DAB in the kit.

Red arrowheads indicate sub-optimal fixation; the endothelial cells are coming away from the basal lamina of the blood vessel.