In the absence of infection, endogenous IL-6 protein was barely detected in the cerebral cortex of WT or TLR7-/- mice, whereas upon EV71 infection IL-6 levels were significantly elevated in the cerebral cortex of WT mice relative to TLR7-/- mice (Fig 6D and 6E, and S7 Fig). This evidence concerns the gene TLR7 and infection.