Fig. 4. Peptide-MHC class II complexes derived from transmembrane anchored I-E localize to late lysosomal compartments of APCs. Macrophages from B10A. (5R) mice that express I-A^b and IE were fixed, permeabilized and stained with Y-Ae and antibodies recognizing LAMP-1, MPR (MPR-300) and cathepsin-D. Y-Ae complexes colocalize with LAMP-1 (A) and cathepsin-D (C), but not with MPR (B). Images are single representative confocal sections. All images on the very right are respective overlays of the stained images of A, B and C. Scale bar, 10 µm.