Perivascular Arrest of CD8+ T Cells Is a Signature of Experimental Cerebral Malaria
Fig 9
Widespread apoptosis or loss of vasculature does not occur in the brains of mice with ECM.
(A-C and K) 106 DsRed+CD8+ OT-I T cells were adoptively transferred into CFP+ P14 host mice, which were subsequently infected with 106 SIINFEKL-expressing Pb-TG pRBCs (n = 4) or left uninfected (n = 5). Mice were intravenously injected with CellEvent Caspase-3/7 Detection Reagent when displaying signs of ECM (day 6 p.i). Brains were subsequently isolated and processed for histological examination. (A) Representative snapshot of an apoptotic cell (green) associated with the cortical vasculature (blue) of the brain taken from a mouse with ECM. (B) Quantification ± SD of apoptotic cells stained with CellEvent per mm3 in brains from infected and uninfected control mice. (C) Representative snapshot showing an apoptotic cell (green) in contact with a parasite-specific CD8+ OT-I T cell (red). Endothelial cells (blue) were visualized by CFP expression. (D-J) C57BL/6 mice were infected with 104 Pb ANKA pRBCs or left uninfected. Brains were removed and processed for histological examination when Pb ANKA mice developed signs of ECM (day 7 p.i.). Representative images demonstrating the (D) absence and (E) rarity of apoptotic cells (green) within the cortex of brains from uninfected and ECM affected mice respectively. Cell nuclei are shown in blue. (F) Quantification ± SD of apoptotic cells stained for activated caspase 3 per mm2 in brains from infected and uninfected control mice. (G-H) Co-staining of activated caspase 3 (green) and CD31 (red) demonstrating an (G) apoptotic endothelial cell and an (H) apoptotic leukocyte within the cortical vasculature of brains taken from ECM affected mice. Cell nuclei are shown in blue. Quantification ± SD of total (I) number and (J) area per mm2 of cortical blood vessels in the brain from uninfected and ECM affected mice. (K) Representative tile scan showing the localization of CellEvent+ apoptotic cells (green/asterisk) in relation to vascular leakage (red) within the brain of an ECM affected (day 6 p.i.) CFP+ P14 mouse. Endothelial cells (blue) were identified by CFP. Scale bars: (A,C) 25 μm, (D,E) 50 μm, (G,H) 25 μm, (L) 1 mm. Results are pooled from mice infected in one experiment. Significance determined by unpaired t test with Welch’s correction.