PTX3 recognizes membrane domains of cells undergoing apoptosis.

Jurkat cells, either alive (upper left quadrant of each panel) or committed to apoptosis by CD95 cross-linking (see “Materials and methods”) were fixed, permeabilized with saponin, and stained with biotinylated PTX3 (50 μg/mL) (panels D and F). Bound molecules were revealed by addition of FITC-streptavidin (panel D and green color in panel F). The fluorescence background obtained in the presence of streptavidin only is shown in panel A and as green color in panel C. Characteristics of the nuclei were revealed by addition of PI (panels B and E and red color in panels C and F).