Figure 2.

GFP-positive monocytes concentrate near plaques in APP+PS1 transgenic animals and exhibit microglial/macrophage phenotype. Imaging of GFP-positive cells was performed using confocal microscopy. Brain sections from APP+PS1 mice collected 1 d after the last of 16 twice weekly injections were stained with fluorescent markers to detect the location and phenotype of the injected monocytes and amyloid plaques. Almost all GFP cells colocalized with CD11b (A–C). Ameboid GFP cells also expressed the phagocyte marker CD68 (D–F), while ramified GFP cells rarely expressed this marker. No GFP-positive cells were detected in uninjected control mice, although CD11b-positive cells were comparable to those in the mice injected with GFP monocytes (G–I). Pictures were taken at 630×. Scale bar, 20 μm.