Journal: bioRxiv
Article Title: Early Binding of Anti-Amyloid Antibodies to CAA Drives Complement Activation, Inflammation and ARIA in Mice
doi: 10.64898/2026.03.04.709591
Figure Lengend Snippet: a, Schematic of acute single-dose immunization in 19-month-old APP NL-G-F KI mice (n=3-4/group) with biotinylated 3D6 or IgG2a mAb (25 mg/kg, i.p.), followed by euthanasia at 24 h. b, Brain sections stained with Amylo-Glo (AG) for amyloid, Collagen-IV for blood vessels’ basement membrane, Streptavidin 555 for biotinylated 3D6 or IgG2a, and endothelial marker CD31 in IgG2a and 3D6-biotinylated mAb-injected mice; images taken from the leptomeningeal penetrating vessels along the cortical pial surface. Arrowheads point towards CAA-bound Streptavidin 555, indicative of biotinylated mAb binding; asterisks indicate plaques. c–d , Brain sections labeled with AG and Streptavidin-AF555 showing biotinylated mAb distribution in c, leptomeningeal vessels, and d, large parenchymal arterioles. Arrowheads indicate CAA-associated mAb binding and C1q deposition observed in 3D6-treated mice. e, Schematic of acute immunization in 25-month-old APP NL-G-F KI mice (n= 7-9/group) treated with anti-Aβ 3D6 IgG2a mAb or IgG2a isotype control. f, Brain sections stained for aggregated Aβ, anti-mouse IgG2a (to detect 3D6 and IgG2a), and C1q in IgG2a control- and 3D6-treated mice. Arrows indicate cerebellar meningeal vessel-associated labeling; asterisks mark parenchymal plaque labeling. Adjacent sections were stained with Prussian blue (counterstained with nuclear fast red) for microhemorrhages and H&E for RBC extravasation. g, Triple labeling with AG, anti-mouse IgG2a, and collagen-IV to distinguish plaque (AG⁺AntiMsIgG2a⁺ColIV⁻) and vascular (AG⁺AntiMsIgG2a⁺ColIV⁺) mAb binding in 3D6-treated brain sections. h, Quantification of % cerebellar plaque vs CAA labeling of mAb in a subset of 3D6 treated mice (n=5), *p < 0.05, paired t-test. Scale bar: b=50 µm; c,d,f =100 µm; g = 250 µm.
Article Snippet: After a quick rinse in MilliQ water, sections were counterstained with Nuclear Fast Red Counterstain (Vector Laboratories, Inc, H-3403-500) followed by dehydration steps in ethanol and Histoclear.
Techniques: Staining, Membrane, Marker, Injection, Binding Assay, Labeling, Control