Cathepsin X colocalizes with the Mac-1 integrin receptor in maturing, adherent DCs. Cathepsin X was labeled with Alexa Fluor 488-labeled mouse 2F12 mAb that recognizes the mature, active form. Absence of colocalization of cathepsin X (green fluorescence) and Mac-1 integrin receptor (red fluorescence) in immature DC (iDC; A) and mature DCs (C) is shown. Differential interference contrast images are shown, respectively. Original bars, 20 μm. Maturing, adherent DCs were labeled by seeding immature DCs onto glass coverslips in 24-well plates in the presence of 20 ng/ml LPS and allowing adherence for 20 h. The translocation of cathepsin X in maturating, adherent DCs to the plasma membrane, where it colocalizes with the Mac-1 integrin receptor, is demonstrated (B). Original scale bars represent 20 μm. Fluorescence microscopy was performed using a Carl Zeiss LSM 510 confocal microscope. Images were analyzed using Carl Zeiss LSM image software 3.0.