Supplementary Figure 14: Extended data from Fig. 7. Anti-Sfrp1 antibodies enter the brain parenchyma via intravenous administration without inducing macrophage infiltration.

A-F) Frontal sections of the brain from APP;PS1 mice injected 24 hrs before in the retro-orbital sinus with biotinylated-versions of either 10.5.6 mAb or unspecific mouse IgG1 as indicated in the panel. Sections were stained with streptavidin-POD followed by tyramide amplification and immunostained for Aβ42. Note the accumulation of the 10.5.6 mAb in the brain parenchyma especially around APs and pia surface, whereas the unspecific IgG1 is poorly detected in comparable sections. G-V) Frontal sections of the brain from APP;PS1 mice treated for 2 months with IgG1 or a-Sfrp1 immunostained with anti-laminin (LN) and CD45 antibodies to visualize blood vessels and infiltrated macrophages respectively. Arrowheads point to macrophages infiltrated in the brain parenchyma whereas arrows to those found within the blood vessels. Note the poor macrophagic infiltration especially in animals treated with a-Sfrp1 IgG. These experiments were repeated three times obtaining similar results. Scale bar: 50 μm A-F; 100 μm G-V.