BMM migration to HIVE affected brain tissue. SPIO-BMM were injected intravenously into HIVE or sham-operated mice. Histology assay examined BMM migration to diseased brain sites. Sections of brain from HIVE (A, C) and sham (B and D) mice were immunostained for HIV-1 p24 (A and B, brown) and GFAP for astrocytes (C and D, brown). Prussian blue staining (blue) revealed SPIO-labeled BMM (A and C, blue) migration into the area of HIV-1 infected MDM 5 days after adoptive transfer of BMM to recipient mice. In sham-operated mice (B and D), no significant BMM migration was detected. Original magnifications, × 200.