Properties of human monocytes/macrophages isolated from the humanized mice. Human CD45⁺CD14⁺CD33⁺ cells from the spleens of human CD34⁺ cells engrafted CSF1^m/m and CSF1^h/h mice were isolated after 12 weeks of transplantation. Human CD45⁺CD14⁺CD33⁺ cells obtained from the fetal liver served as controls. Cells were stimulated in vitro with LPS either for 24 or 48 hours, cell culture supernatants were collected and the levels of human TNFα (A) and IL-6 (B) were quantified through ELISA. Shown are the mean values of triplicate samples. Error bars indicate ± SEM. (C) Human CD45⁺CD14⁺CD33⁺ cells were stimulated poly I:C for either 6 or 12 hours and the IFNα (left) and IFNβ (right) mRNA levels were quantified through Real Time PCR. Shown are the mean values of duplicate samples. (D) Human CD45⁺CD14⁺CD33⁺ cells were isolated from the humanized mice and incubated with FITC-labeled bacteria at 37°C either for 30 or 60 minutes and measured by flow cytometry. Cells incubated with FITC-labeled bacteria on ice served as controls. Open histograms represent cells obtained from the CSF1^m/m mice, dotted histograms represent cells obtained from the CSF1^h/h mice and filled histograms represent cells obtained from human fetal liver. (E) Human CD45⁺CD14⁺CD33⁺ cells isolated from CSF1^m/m mice, CSF1^h/h mice and human fetal liver were kept in the upper wells and the medium containing MIP3β was added in the lower wells. Cells were incubated for either 30 or 60 minutes and the number of cells migrated from the upper wells to the lower wells was calculated and plotted. Shown are the mean values of duplicate samples. (F) Human CD45⁺CD14⁺CD33⁺ cells isolated from CSF1^m/m mice, CSF1^h/h mice and human fetal liver were cultured either in the presence or in the absence of LPS. After 24 hours of stimulation, cells were stained with indicated surface markers and measured by flow cytometry. Open histograms represent cells obtained from the CSF1^m/m mice, dotted histograms represent cells obtained from the CSF1^h/h mice and filled histograms represent cells obtained from human fetal liver.