First, to better differentiate brain-resident myeloid cells, including microglia, from invading monocytes in the TMEV encephalitis model of TLE, we compared virus-induced effects in B6 WT vs. B6-based Cx3cr1-creER±tdTomatoSt/Wt mice, in which long-lived CX3CR1+ cells such as microglia can be distinguished from infiltrating monocytes by the expression of the red fluorescent protein tdTomato (Käufer et al., 2018a). The gene discussed is CX3CR1; the disease is viral encephalitis.