Immunity Article Stroma-Derived Interleukin-34 Controls the Development and Maintenance of Langerhans Cells and the Maintenance of Microglia Melanie Greter,1,9,* Iva Lelios,1,9 Pawel Pelczar,2 Guillaume Hoeffel,3 Jeremy Price,4,5 Marylene Leboeuf,4,5 Thomas M. Ku¨ndig,7 Karl Frei,8 Florent Ginhoux,3 Miriam Merad,4,5,6,10,* and Burkhard Becher1,10 1Institute of Experimental Immunology, Neuroimmunology 2Institute of Laboratory Animal Science University of Zu¨ rich, CH 8006 Zu¨ rich, Switzerland 3Singapore Immunology Network (SIgN), Agency for Science, Technology and Research (ASTAR), BIOPOLIS, 138648, Singapore 4Department of Oncological Sciences 5The Immunology Institute 6Tisch Cancer Institute Mount Sinai School of Medicine, New York, NY 10029, USA 7Clinical Tumor Biology & Immunotherapy Unit 8Department of Neurosurgery University Hospital Zu¨ rich, 8091 Zu¨ rich, Switzerland 9These authors contributed equally to this work 10These authors contributed equally to this work *Correspondence:
[email protected] (M.G.),
[email protected] (M.M.) http://dx.doi.org/10.1016/j.immuni.2012.11.001 SUMMARY the first immune barrier to foreign antigens that breach the skin. Microglia represent the resident macrophages of the Colony stimulating factor-1 (Csf-1) receptor and its CNS and are considered the first line of defense in many CNS ligand Csf-1 control macrophage development, main- pathologies. Most lymphoid and nonlymphoid tissue DCs and tenance, and function. The development of both macrophages are constantly repopulated by blood-derived Langerhans cells (LCs) and microglia is highly depen- circulating myeloid precursors. In contrast, epidermal LCs and dent on Csf-1 receptor signaling but independent microglia derive from embryonic precursors that take residence of Csf-1.