Temporal and regional changes in donor-derived T-cell infiltration. (A) Schematic of coronal brain section (based on Paxinos and Franklin³⁵) indicating the regions examined with immunofluorescence: hippocampus, habenula, meninges, cortex, and choroid plexus (located in the lateral ventricular spaces). Blue shaded region of the hippocampus identifies the dentate gyrus (DG) containing the granule cell layer (GCL). Surrounding regions include the cornu ammonis 1 (CA1) and 3 (CA3). (B-F) Representative images of donor RFP⁺ T-cell infiltrate in brain regions of interest, with respective quantification at days 14, 35, and 70 after transplant: meninges (B), choroid plexus (in lateral ventricle outlined by white dashes) (C), cortex (D), hippocampus (E), and habenula (F) (day 14: n = 4-7; data pooled from 2 independent experiments; day 35: n = 6-7; data pooled from 2 independent experiments; day 70: n = 9-11; data pooled from 2 independent experiments). Original magnification ×20; scale bars, 50 μm. Data are presented as mean ± standard error of the mean. Significant differences calculated with 1-way analysis of variance with Tukey multiple comparisons test. *P < .05, **P < .01, ***P < .001.