Aminopeptidase N (CD13) Is Involved in Phagocytic Processes in Human Dendritic Cells and Macrophages
Figure 3
CD13 cross-linking enhances phagocytosis of E. coli by MD-Ms but not by MD-DCs. Cells were incubated with F(ab′)2 fragments of anti-CD13 mAb at 4°C. After washing, the cells were incubated with 12 μg of E. coli-FITC, in the presence (CD13xl) or absence of F(ab′)2 fragments of goat anti-mouse antibodies for 60 min (MD-DCs) or 30 min (MD-Ms) at 37°C. The phagocytic index (geometric mean of fluorescence intensity multiplied by the percentage of positive cells) (a) and the percentage of fluorescence positive cells (% of phagocytosis) (b) were determined using flow cytometry. Data from each donor were normalized considering the value obtained in the absence of CD13 cross-linking as 100%. (a) and (b) show the averages of 6 experiments with cells from different donors, *. (c) and (d) show representative histograms of an experiment with MD-DCs (c) and MD-Ms (d) from a single donor, after trypan blue; dotted lines: cells incubated with E. coli at 4°C; gray lines: cells incubated with E. coli at 37°C; black lines: cells incubated with E. coli at 37°C in the presence of CD13 cross-linking. The percentages of FITC+ cells were 36 and 38% for MD-DCs and 54 and 69% for MD-Ms without and with CD13 cross-linking, respectively.
