title: Natural type I interferon-producing cells as a link between innate and adaptive immunity.
abstract: Type I interferons (IFNs) are promptly produced upon invasion of pathogens, and activate a broad range of effector cells in the innate and adaptive immune system. Lin(-)CD4(+)CD11c(-) plasmacytoid dendritic cell precursors (plasmacytoid pre-DCs) produce enormous amounts of type I IFNs in response to viruses and CpG DNA, thus corresponding to the previously described but not fully defined natural type I IFN-producing cells (IPCs). Plasmacytoid pre-DCs strongly express toll-like receptor (TLR) 7 and TLR9, in contrast to monocytes, which mainly express TLR1, 2, 4, 5, and 8, suggesting that these two DC precursors recognize different microbial molecules and that they may have developed through different evolutionary trails. Three different stimuli, CpG DNA plus CD40 ligand, interleukin-3 (IL-3), and herpes simplex virus, stimulate plasmacytoid pre-DCs to differentiate into DCs that induce distinct types of T helper cells, i.e., Th1, Th2, and IFN-gamma- and IL-10-producing T cells, respectively. The remarkable versatility of plasmacytoid pre-DCs distinguishes them from other cell types in the immune system that have only limited functions, and suggests that these cells may play a key role in integrating the innate and adaptive aspects of various immune responses.
authors.affiliation: Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan. kadowaki@kuhp.kyoto-u.ac.jp
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Kadowaki
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Liu
mesh_terms: D002454:Cell Differentiation; D003713:Dendritic Cells / Q000276:immunology* / Q000502:physiology; D006801:Humans; D007113:Immunity, Innate; D007370:Interferon Type I / Q000096:biosynthesis*; D008562:Membrane Glycoproteins / Q000276:immunology; D011956:Receptors, Cell Surface / Q000276:immunology; D051194:Toll-Like Receptor 1; D051199:Toll-Like Receptor 7; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors
chemical_list: D007370:Interferon Type I; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C495348:TLR7 protein, human; C495371:TLR9 protein, human; D051194:Toll-Like Receptor 1; D051199:Toll-Like Receptor 7; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors