Localization of MHC class II molecules in murine bone marrow-derived macrophages.
The localization of MHC class II molecules (Ia) was studied by ultrastructural immunocytochemistry in murine bone marrow-derived macrophages stimulated by recombinant interferon-gamma (rIFN-gamma). Ia molecules were detected on the plasma membrane and on the limiting membrane and internal structures of vesicular acidic compartments. Some of these vesicules also contained cathepsin B and/or cathepsin D. The use of BSA-gold, a marker of fluid phase endocytosis, allowed the identification of Ia-positive organelles as endocytic compartments. The first to be labelled with BSA-gold also contained the cation-independent mannose 6-phosphate receptor (MPR) but not the 120,000 molecular weights lysosomal glycoprotein (lgp 120). Later on, BSA-gold appeared in Ia+, MPR+, lgp 120+ compartments. Collectively these data suggest that intracellular Ia molecules are mainly present in early and late endosomes.
Lang
T
T
Département de Biologie Moléculaire, Institut Pasteur, Paris, France.
Antoine
J C
JC
D000818:Animals; D015703:Antigens, CD; D001853:Bone Marrow / Q000276:immunology*; D002403:Cathepsins / Q000032:analysis; D004705:Endocytosis / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D007124:Immunoenzyme Techniques; D051907:Lysosomal Membrane Proteins; D008264:Macrophages / Q000276:immunology* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D017527:Receptor, IGF Type 2; D011956:Receptors, Cell Surface / Q000032:analysis
D015703:Antigens, CD; D000949:Histocompatibility Antigens Class II; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D017527:Receptor, IGF Type 2; D011956:Receptors, Cell Surface; D002403:Cathepsins