FITC-dextran uptake assay of macrophages from the three different sources. (A) Purified macrophages were incubated with FITC-dextran at 37°C for 45 min, and then washed extensively to remove excess FITC-dextran, followed by FACS analysis. Representative histograms are shown. Solid grey histograms represent control groups; solid red lines represent the percentage of phagocytic macrophages. (B) Group histograms showing both population and median fluorescence intensity (MFI) values. Data are the mean ± SEM from five separate experiments. *p < 0.05.