title: Tim-3 mediates phagocytosis of apoptotic cells and cross-presentation.
abstract: Phagocytes such as macrophages and dendritic cells (DCs) engulf apoptotic cells to maintain peripheral immune tolerance. However, the mechanism for the recognition of dying cells by phagocytes is not fully understood. Here, we demonstrate that T-cell immunoglobulin mucin-3 (Tim-3) recognizes apoptotic cells through the FG loop in the IgV domain, and is crucial for clearance of apoptotic cells by phagocytes. Whereas Tim-4 is highly expressed on peritoneal resident macrophages, Tim-3 is expressed on peritoneal exudate macrophages, monocytes, and splenic DCs, indicating distinct Tim-mediated phagocytic pathways used by different phagocytes. Furthermore, phagocytosis of apoptotic cells by CD8(+) DCs is inhibited by anti-Tim-3 mAb, resulting in a reduced cross-presentation of dying cell-associated antigens in vitro and in vivo. Administration of anti-Tim-3 as well as anti-Tim-4 mAb induces autoantibody production. These results indicate a crucial role for Tim-3 in phagocytosis of apoptotic cells and cross-presentation, which may be linked to peripheral tolerance.
authors.affiliation: Department of Immunology, Biomedical Research Center, Juntendo University School of Medicine, Tokyo, Japan. nakayama@juntendo.ac.jp
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakayama
authors.forename: Hisaya
authors.initials: H
authors.lastname: Akiba
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Takeda
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kojima
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hashiguchi
authors.forename: Miyuki
authors.initials: M
authors.lastname: Azuma
authors.forename: Hideo
authors.initials: H
authors.lastname: Yagita
authors.forename: Ko
authors.initials: K
authors.lastname: Okumura
mesh_terms: D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D017951:Antigen Presentation / Q000187:drug effects / Q000276:immunology*; D017209:Apoptosis / Q000276:immunology*; D016827:CD8 Antigens / Q000276:immunology; D002460:Cell Line; D003713:Dendritic Cells / Q000276:immunology*; D000072597:Hepatitis A Virus Cellular Receptor 2; D007108:Immune Tolerance / Q000187:drug effects / Q000502:physiology*; D017737:Macrophages, Peritoneal / Q000276:immunology*; D051379:Mice; D010587:Phagocytosis / Q000276:immunology*; D051381:Rats; D011991:Receptors, Virus / Q000037:antagonists & inhibitors / Q000276:immunology*
chemical_list: D000906:Antibodies; D016827:CD8 Antigens; C442241:Havcr2 protein, mouse; D000072597:Hepatitis A Virus Cellular Receptor 2; D011991:Receptors, Virus