Neuronal CCL2 expression drives inflammatory monocyte infiltration into the brain during acute virus infection

Charles L Howe; Reghann G. LaFrance-Corey; Emma N Goddery; Kanish Mirchia

The known and putative ligands for CCR2 are CCL2, CCL7, CCL8, CCL12, CCL13, and CCL16 [23] . Of these, only CCL2 and CCL7 were expressed at detectable levels in our mice (Figure 1 ). To determine the relative contribution of these two chemokines to inflammatory monocyte recruitment during acute TMEV infection we used immunodepletion to neutralize each factor. LysM-GFP monocyte-neutrophil reporter mice [4] received 20 µg goat anti-CCL2 IgG, 20 µg goat anti-CCL7, or 20 µg goat IgG by intraperitoneal injection at -12, 0, and +12 hr relative to time of infection. Brain-infiltrating leukocytes were isolated at 24 hpi and analyzed by flow cytometry to count inflammatory monocytes (CD45 + GFP mid ) and neutrophils (CD45 + GFP hi ) (Figure 4 ). Mice treated with control IgG had approximately 5000 monocytes and 4000 neutrophils ( Figure