Fig. 3. scar^- cells contain mostly small acidic vesicles. Phase contrast (A,C) and fluorescent (B,D) microscopic images of control (A,B) and scar^- cells (C,D). (A-D) Cells were incubated with FITC-dextran for 1 hour, washed and spotted onto coverslips prior to examination. In control cells (A,B), vesicles of many different sizes were present, including large post-lysosomal and macropinosomal vesicles (arrows). By contrast, scar^- cells contained primarily smaller vesicles. (E,F) scar^- cells were incubated with RITC-dextran for 1 hour, washed and further incubated with Lysosensor Green for 10 minutes. After spotting cells on coverslips, they were examined using the red channel (E) or the green channel (F) of the fluorescence microscope. Most of the RITC-dextran-positive vesicles (E) also stained with Lysosensor Green (F), indicating that most of the vesicles in the scar^- cells were acidic. Bar, 5 µm.