Topical application of GB119 to a brain tumor on the dorsal surface labels the tumor's edge more robustly than the tumor's center.
(a) Monochromatic image of a whole brain with a tumor growing near the dorsal surface (arrow) showing the treated areas (outlines). (b) Unmixed false colored map of pixel intensity representing activated GB119 at 35 minutes post application. (c) Horizontal H&E stained section showing higher magnification of square area in panel b demonstrating tumor mass and normal surrounding brain. (d) Adjacent sections revealing human vimentin positive cells labeling tumor edge and center (false colored green), (e) activated GB119 (Cy5, false colored red) revealing infiltrating cells, the tumor margin and to a lesser degree the interior of the tumor and (f) merged imaged demonstrating co-registration (yellow) of GB119-labeled cells and vimentin positive cells within the tumor mass (arrows) and outside of the main tumor mass, arrow head. (g) GB119 labeled cells at the tumor's edge more robustly than at the tumor's center, although not significantly, p = 0.124. (h and i) reveal that GB119 is associated with CD11b-positive cells, but only when they are tumor associated, (h) is a typical image observed from within the tumor interior and (i) shows the images typical of the tumor – brain interface. Note that only CD11b positive cells associated with normal brain do not activate the probe. Section thickness 25 µm (d–f) and 10 µm (h,i). Scale bar, 5 µm (a,b), and 100 µm (c–f, h,i).