Fig 3. TLR7 promotes EV71-induced neural pathogenesis in the murine cerebral cortex.

(A–C) Three-day-old neonatal WT and TLR7^-/- mice were intracranially injected with 10 μl PBS or EV71 per mouse (each PBS group, n = 8; each EV71 group, n = 10). The weight (A), clinical score (B), and Kaplan-Meier survival curve (C) were recorded from day 1 to 7 post EV71 incubation. Data are shown as mean ± SD. **, P < 0.01; ***, P < 0.001. (D–G) WT mice and TLR7^-/- mice mock-infected or EV71-infected were sacrificed on 2, 3, 5, and 7 days post-infection (each group, n = 3–5). EV71 virus from brain tissues homogenate was subjected to plaque formation assay. The EV71 titers in brain tissues of mice (per gram) were quantified (D). Graphs show means ± SD. ns, non-significant. The RNA was extracted from the brain tissues and EV71 RNA copies were quantified in brain tissues of mice (per gram) using absolute quantitative PCR (E). Graphs show means ± SD. ns, non-significant. The mice brain sections on day 3 post EV71 incubation were fixed and subjected to IHC staining with dsRNA antibody (Brown) (F). The presentative images were acquired using light microscopy. Bar = 100 μm. The dsRNA relative expression was shown as a dsRNA positive index and quantified with Image J software. Graphs show means ± SD. ns, non-significant. Immunostaining of the brain’s cortex from day 3 and 5 post EV71 incubation was probed with Neurofilament (Red), EV71 VP1 (Green), and stained with DAPI (Blue) (G). The presentative images were acquired using fluorescence microscopy. Bar = 20 μm.