Peripheral lipopolysaccharide induces microglia/monocyte M2b-type activation and CCR2 overexpression in both cell types. Brain sections from saline- and lipopolysaccharide (LPS)-injected mice were stained with ionized calcium binding adaptor molecule 1 (Iba-1) antibody (A) (n = 3) or cells were prepared for flow cytometry analysis (B-E). (A) Representative pictures of Iba-1 immunoreactive cells in the hippocampus of brains from saline (left) and LPS-injected (right) mice. (B, D) Histograms of average percentage of microglia (B) or inflammatory monocytes (D) expressing CCR2 (left) and TLR4/CD14 complex (right) in live single immune cell suspensions from brains of saline- (white bars) and LPS-injected mice (black bars). (C,E) Graphs and histograms of mean fluorescent intensity for CD80 (left) and CD124/IL-4Rα (right) in enriched microglia (C) and enriched central nervous system (CNS)-associated phagocyte (E) populations from brains of saline- (white bars) and LPS-treated mice (black bars). Bars represent the mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.005 versus saline control; n = 4.