Fig. 2: Neutrophils migrate into the brain during disease progression in APP/PS1 mice.

Representative confocal images of NE⁺ leukocytes (red cells) in the 3V (A), around the hippocampal area (left panels in B), and the choroid plexus (right panels in B). MPO⁺ leukocytes (red cells) in the meninges and parenchyma where Aβ plaque (green staining) is deposited (C) and around brain vessels (right panels in D) in 8- to 9-month-old APP/PS1 mice. The brain vessels were identified based on Hoechst staining 3D using Zen software. Quantification of the number of NE⁺ (E) and MPO⁺ (F) cells in the hippocampus, 3V, blood vessels and pia mater in APP/PS1 mice treated with anti-Ly6G antibody or isotype control antibody (data are presented as the mean ± s.e.m.; unpaired Student’s two-tailed t test, n = 5–6; **p < 0.01; ***p < 0.001). G, H Flow cytometry analysis of hyperreactive neutrophils infiltrating the brain, as reflected by CXCR4^hi/CD62L^lo staining in APP/PS1 mice treated with serum or anti-Ly6G antibody and WT controls (n = 4–5). One-way ANOVA followed by Bonferroni multiple comparison tests. ***p < 0.001. Hip hippocampus, 3V third ventricle, DG dentate gyrus, CP choroid plexus, Scale bar: 20 μm in A and B; 50 μm in C and D.