Human Epidermal Langerhans Cells Cointernalize by Receptor-Mediated Endocytosis ``Nonclassical'' Major Histocompatibility Complex Class I Molecules (T6 Antigens) and Class II Molecules (HLA-DR Antigens)

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 84; no. 9; pp. 2901 - 2905
• Main Authors: Hanau, Daniel, Fabre, Michel, Schmitt, Didier A., Garaud, Jean-Claude, Pauly, Gilles, Tongio, Marie-Marthe, Mayer, Simone, Cazenave, Jean-Pierre
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 01.05.1987; National Acad Sciences
• Subjects: Antigens; Antigens, Differentiation, T-Lymphocyte; Antigens, Surface - genetics; Biological and medical sciences; Cell membranes; Cell physiology; Endocytosis; Epidermal cells; Fundamental and applied biological sciences. Psychology; Haptens; HLA-D Antigens - genetics; HLA-DR Antigens - genetics; Humans; Internalization; Islets of Langerhans; Langerhans Cells - immunology; Langerhans Cells - ultrastructure; Major Histocompatibility Complex; Microscopy, Electron; Molecular and cellular biology; Molecules; Organelles; Receptors, Immunologic - analysis; T lymphocytes; Antigen; Endocytosis; Langerhans cell; Internalization; HLA-DR-System; Major histocompatibility system; Epidermis
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.84.9.2901

HLA-DR and T6 surface antigens are expressed only by Langerhans cells and indeterminate cells in normal human epidermis. We have previously demonstrated that T6 antigens are internalized in Langerhans cells and indeterminate cells by receptor-mediated endocytosis. This process is induced by the binding of BL6, a monoclonal antibody directed against T6 antigens. In the present study, using a monoclonal antibody directed against HLA-DR antigens, on human epidermal cells in suspension, we show that the surface HLA-DR antigens are also internalized by receptor-mediated endocytosis in Langerhans and indeterminate cells. Moreover, using immunogold double labeling, we demonstrate that T6 and HLA-DR antigens are internalized through common coated regions of the membrane of Langerhans or indeterminate cells. The receptor-mediated endocytosis that is induced involves coated pits and vesicles, receptosomes, lysosomes, and also, in Langerhans cells, the Birbeck granules. Thus, T6 antigens, which are considered to be ``unusual'' or ``nonclassical'' major histocompatibility complex class I molecules, and the major histocompatibility complex class II molecules, HLA-DR, are internalized in Langerhans and indeterminate cells through common receptor-mediated endocytosis organelles.