Figure 3.
Western blot analysis of MHC class II, Ii, and calnexin in whole D1 cells and exosomes. (A) 10, 3, or 1 μg of proteins from whole cell lysate (Cells) or exosomes (Exos) was loaded on a 12% SDS gel followed by Western blotting using antibodies against MHC class II molecules (MHC II), Ii, and calnexin (Calnex). MHC class II are enriched in exosomes compared with whole cells, whereas Ii and calnexin are absent from exosomes. (B) 90 μg of exosomes was loaded on a continuous sucrose gradient (0.25–2 M sucrose, resulting in densities ranging 1–1.5 g/ml), and the fractions were analyzed by Western blot using the anti–MHC class II antibody. Exosome-associated MHC class II molecules float at an average density of 1.14 g/ml.