FIGURE 1.

uPAR enhances phagocytosis independent of αvβ5 integrin. a, percentage of transfected green CS-1 cells that are positive for red-labeled apoptotic cells after 2 h of co-culture. CS-1 cells were transfected with pCx-EGFP or co-transfected with pCx-EGFP and pN1-uPAR or pN1-uPAR and β5-pCx or pN1-uPAR and the non-functional deletion mutant of β5 (ΔC-pCx). b, fold change in mean geometric intensity of the red channel (Y geometric mean) in the upper right quadrant that is representative of double positive population was measured. Values represent the amount of apoptotic material engulfed by phagocytes. Data are representative of at least three different experiments. c, uptake of viable or apoptotic T cells by EGFP and uPAR overexpressing cells after 2 h of co-culture. Co-culture of viable CEM-1 cells with transfected CS-1 cells resulted in ∼5% double-positive cells that correspond to basal cell death level in culture conditions in vitro. Panels on the right show graphical output of flow cytometry analysis showing engulfment represented in the upper right quadrant. d, the amino acid residues spanning each of the truncation mutants are depicted schematically. CS-1 cells were transfected with pCx-EGFP alone or together with the GPI-anchor containing pcDNA3-uPAR domain constructs as indicated, and a phagocytosis assay was performed. Values were normalized against D1D2D3, which was set at 100%. Asterisk, p < 0.05.