TLR4 and infection: HSV-1 was introduced to nine mice by intranasal inoculation, andafter 60 days the viral ICP4 protein (which activates transcriptionduring infection) of HSV-1 was found in trigeminal ganglia and thecerebral cortex, with many inflammatory biomarkers present, includinginterferons (IFN) α/β and Toll-like receptor 4 (TLR4)in trigeminal ganglia and the cerebral cortex.51,52 Yao et al. showed that the viral load of HSV-1 in the brain washigher than in trigeminal ganglia in mice infected with HSV-1, suggestingthat HSV-1 could reactivate in the brain.53