TLR7 and infection: We observed no differences in mtSOX levels in WT and TLR7−/− pDCs prior to infection, but mice infected with LCMV Cl13 showed reduced levels of mtSOX specifically in the WT compartment (Fig. 2n, o) suggesting that, like functional exhaustion30, loss of mtSOX production is cell intrinsically dependent on TLR7 signaling in pDCs.