CCR2 and infection: While we initially expected that abrogation of CCR2 would reduce primarily the Ly6Chi inflammatory monocytes, we found that also the Ly6Clo monocytes were affected in various ways during Orientia infection: In CCR2-deficient animals, Orientia infection induced significantly lower concentrations of Ly6Clo monocytes in peripheral blood and the lungs, and also the expression of MHCII and F4/80 by pulmonary Ly6Clo monocytes was significantly decreased during infection in CCR2-/- mice.