title: Plasmacytoid dendritic cell dichotomy: identification of IFN-α producing cells as a phenotypically and functionally distinct subset.
abstract: Plasmacytoid dendritic cells (pDC) produce large amounts of type I IFN in response to invading pathogens, but can also suppress immune responses and promote tolerance. In this study, we show that in mice, these functions are attributable to two distinct pDC subsets, one of which gives rise to the other. CD9(pos)Siglec-H(low) pDC secrete IFN-α when stimulated with TLR agonists, induce CTLs, and promote protective antitumor immunity. By contrast, CD9(neg)Siglec-H(high) pDC secrete negligible amounts of IFN-α, induce Foxp3(+) CD4(+) T cells, and fail to promote antitumor immunity. Although newly formed pDC in the bone marrow are CD9(pos) and are capable of producing IFN-α, after these cells traffic to peripheral tissues, they lose CD9 expression and the ability to produce IFN-α. We propose that newly generated pDC mobilized from the bone marrow, rather than tissue-resident pDC, are the major source of IFN-α in infected hosts.
authors.affiliation: Department of Pathology, Stanford University, Palo Alto, CA 94304, USA.
authors.forename: Pia
authors.initials: P
authors.lastname: Björck
authors.forename: H Xianne
authors.initials: HX
authors.lastname: Leong
authors.forename: Edgar G
authors.initials: EG
authors.lastname: Engleman
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D045744:Cell Line, Tumor; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D005260:Female; D007108:Immune Tolerance; D016130:Immunophenotyping; D016898:Interferon-alpha / Q000096:biosynthesis*; D008297:Male; D008546:Melanoma, Experimental; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000378:metabolism; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D060245:Tetraspanin 29
chemical_list: D015703:Antigens, CD; C554870:Cd9 protein, mouse; D016207:Cytokines; D016898:Interferon-alpha; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29