Fig. 5

Inflammatory monocytes are highly abundant around vascular amyloid deposits and are associated with microhemorrhages in 3D6 treated PDAPP mice. (a) Double immunofluorescence of amyloid (Thio-S, green) and leukocytes (GR-1, red) in PDAPP mice treated with 3D6 or IgG control. Thio-S and GR-1 (red) immunoreactivity overlay (Merge). (b) Quantification of GR-1⁺ area (%) of IgG or 3D6 treated mice. (c) Quantification of GR-1⁺ cells around vascular amyloid deposits of IgG or 3D6 treated mice. (d) Double immunofluorescence of amyloid (Thio-S, green) and monocytes (CCR2, red) in PDAPP mice treated with 3D6 or IgG control. Thio-S and CCR2 (red) immunoreactivity overlay (Merge). (e) Quantification of CCR2⁺ area (%) of IgG or 3D6 treated mice. (f) Quantification of CCR2⁺ cells around vascular amyloid deposits of IgG or 3D6 treated mice The number of vascular amyloid deposits analyzed was 8–10 per animal. (g) Triple labeling of amyloid (Thio-S, green), Prussian Blue (hemosiderin, blue), and immune cells (microglia, macrophages, and monocytes, red) revealed hemosiderin-laden monocytes near CAA-associated microhemorrhages after 3D6 treatment. (h) Quantification of the proportion of Hemosiderin⁺ immune cells in 3D6 treated PDAPP mice. For quantifications, eight to seventeen images were used for each experiment n = 6 (mice), and 140–200 cells were counted. Asterisks indicate significant differences, where ** p < 0.01 and ****p < 0.0001 by unpaired Student’s t test. All are representative images of 26-month-old PDAPP mice. Scale bar 10 μm inset or 20 μm merge, respectively