1. ^*UMR 144 CNRS-Institut Curie, Laboratoire "Mécanismes Moléculaires du Transport Intracellulaire", Institut Curie, Paris Cedex, France
2. ^†INSERM E 0345 "Biologie des Cellules Dendritiques Humaines" Strasbourg Cedex, France
3. ^‡INSERM U 311, Etablissement Français du Sang-Alsace, Strasbourg Cedex, France

Correspondence: Daniel Hanau, MD, INSERM E 0345, EFS-Alsace, 10 rue Spielmann, BP 36, 67065 Strasbourg Cedex, France. Email: daniel.hanau@efs-alsace.fr

¹The first two authors contributed equally to the work.

Received 23 October 2003; Revised 27 February 2004; Accepted 2 March 2004; Published online 30 June 2003.

Abstract

Birbeck granules (BG) are organelles specific to Langerhans cells (LCs), which form where the C-type lectin Langerin accumulates. Their function remains obscure due to morphologic and dynamic alterations induced by maturation of isolated LC. In this study, we attempted to reconstitute Langerin traffic and BG formation in the endosomal pathway of a human melanoma cell line. In the selected Langerin-transfected cell line, M10-22E, Langerin is distributed between the early recycling endosomal compartment and the plasma membrane, as in LC. Whereas mainly concentrated in membranes related to the Rab11⁺ endosomal recycling compartment at the steady state, Langerin also recycles in M10-22E cells and drives BG biogenesis in the endosomal recycling compartment. Interruption of endocytosis or recycling induces redistribution of intracellular Langerin with an associated alteration in BG location and morphology. We have, therefore, generated a stable, Langerin-transfected cell line in which Langerin traffic and distribution and BG morphology replicate that seen in freshly isolated LC. This practical model can now be used to further delineate the nature and function of BG.