Adhesion molecule blockade displaces PbA-specific CD8⁺ T cell from cerebral blood vessels and promotes survival.

(A) Representative maximal projections of 3D time lapses captured through the thinned skull window of a mouse seeded i.v. with 10⁴ naïve mCerulean⁺ OT-I cells (green) and then infected with PbA-OVA-mCherry. Images were captured at d6 p.i. The left panel shows the distribution of OT-I cells along cerebral blood vessels (red) before antibody blockade and the right panel depicts the same vessel after treatment. See corresponding S9 Movie. (B and C) The bar graphs show quantification of luminal PbA-specific CD8⁺ T cells as a percentage of maximum number in brain vasculature at the denoted time points before and after i.v. treatment with anti-LFA-1 / VLA-4 (B) or isotype control antibodies (C). Data are representative of 4–5 independent experiments. (D) Quantification of PbA-specific CD8⁺ T cells in the brain parenchyma as a percentage of the maximum number after i.v. treatment with anti-LFA-1/VLA-4 antibodies. Data are representative of 5 independent experiments. (E) Representative confocal images of the brainstem from mice at d6 p.i. following propidium iodide (red) injection and immunohistochemical staining for NeuN⁺ neurons (green). Mice were treated with either isotype control antibody (top) or anti-LFA-1/VLA-4 blocking antibodies (Ad block) at d5.5 p.i. Cell nuclei are shown in blue. (F) The bar graph shows quantification of data shown in (E). Each bar represents the total number of brainstem cells that are PI⁺ (gray), and within the bar, the red coloration shows the proportion that are also NeuN⁺ (mean ± SD; n = 4 mice per group; 1 brain section per mouse; 4 images per brain section). Asterisks denote a statistically significant difference from all other groups (***P < 0.05).