Figure 3

Increase in number of old microhemorrhages following passive immunization. (A-H) Sections are stained for hemosiderin (extravenous iron in blue) with Prussian Blue and cells counterstained with nuclear fast red (A-G) Panels show the cortex of either a wildtype control mouse (A), APPPS1 transgenic mouse treated with control antibody 16B5 (C) or 10D5 treated APPPS1 mouse lacking the transferred T cells (E). The arrow in (G) denotes a massive clustering of hemosiderin positive microglia in T cell transferred mice following IgG αAβ treatment. (B-H) Panels are a higher magnification of the cortical area shown in (A-G). (I) Quantification of Prussian Blue staining illustrated as the number of positive profiles per brain. Note the fourfold increase in hemorrhage frequency in APPPS1 transgenic mice which received T cells and were passively immunized. Scale bars, 100 μm (A,C,E,G), 50 μm (B,D,F,H).