CIA enhances macrophages at the leptomeningeal and perivascular regions and BBB permeability in APP/PS1 mice. (A) Fluorescence photomicrographs of cortical areas immunolabeled with rat monoclonal anti-CD206 4 months after injection of 2-month-old wild-type (Tg-) and APP/PS1 (Tg+) mice with vehicle or CIA. Note increased leptomeningeal (top row) and perivascular (bottom row) macrophages in Tg- and Tg+ mice treated with CIA. Scale bar = 200 μm. (B) Western blot of IgG in combined cortical and hippocampal samples 4 months after CIA injection into Tg- and Tg+ mice. (C) IgG levels were analyzed 1.5 months (Tg- vehicle, n = 3; Tg- CIA, n = 3; Tg+ vehicle, n = 3; and Tg+ CIA, n = 4) and 4 months after vehicle or CIA injection into Tg- and Tg+ mice (Tg- vehicle, n = 3; Tg- CIA, n = 4; Tg+ vehicle, n = 4; and Tg+ CIA, n = 4).