Intracellular distribution of MHC class I molecules. (A-B) Detection of MHC-I molecules by CLSM examinations (central optical sections) in DCs analyzed using different markers, to identify the localization of MHC-I (green) in ER (calnexin), early endosomes (Rab5 and EEA-1) and late endosomes (Rab7), all detected in red. Cells were stained with anti–TAP-1 (green) or anti-calreticulin (red) associated with Rab5 (red) and EEA-1 (green) markers, respectively, to evaluate the distribution of these molecules in early endosomes. Colocalizations were detected in yellow. Insets represent separate channel images. (C-D) Triple staining of DCs using the markers calnexin (red), MHC-I (gray), and EEA-1 (green). Colocalization is showed in merged images. Experiments in all panels were independently repeated at least 3 times with similar results.