title: Plasmacytoid dendritic cells are activated by Toxoplasma gondii to present antigen and produce cytokines.
abstract: Infection with the parasite Toxoplasma gondii leads to the induction of a Th1-type response dominated by IFN-gamma production and control of this pathogen. Cells of the innate immune system are essential in initiating this response both through the production of IL-12 as well as the presentation of parasite-derived Ags to MHC-restricted T cells. Although dendritic cells (DCs) have been implicated in these events, the contribution of individual DC populations remains unclear. Therefore, multiparameter flow cytometry was used to identify and characterize subsets of murine DCs during acute toxoplasmosis. This approach confirmed that infection leads to the expansion and activation of conventional DC (cDC) subsets. Unexpectedly, however, this analysis further revealed that plasmacytoid DCs are also expanded and that these cells up-regulate MHC class II and costimulatory molecules associated with their acquired ability to prime naive CD4(+) T cells. Furthermore, T. gondii-activated plasmacytoid DCs produce high levels of IL-12 and both plasmacytoid DC maturation and cytokine production are dependent on TLR11. Together these studies suggest that pDCs are a prominent DC subset involved in the initial stages of T. gondii infection, presenting parasite Ags and producing cytokines that are important for controlling infection.
authors.affiliation: Department of Pathobiology, University of Pennsylvania, 380 South University Avenue, Philadelphia, PA 19104, USA.
authors.forename: Marion
authors.initials: M
authors.lastname: Pepper
authors.forename: Florence
authors.initials: F
authors.lastname: Dzierszinski
authors.forename: Emma
authors.initials: E
authors.lastname: Wilson
authors.forename: Elia
authors.initials: E
authors.lastname: Tait
authors.forename: Qun
authors.initials: Q
authors.lastname: Fang
authors.forename: Felix
authors.initials: F
authors.lastname: Yarovinsky
authors.forename: Terri M
authors.initials: TM
authors.lastname: Laufer
authors.forename: David
authors.initials: D
authors.lastname: Roos
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Hunter
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000235:genetics / Q000276:immunology; D000953:Antigens, Protozoan / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D007371:Interferon-gamma / Q000235:genetics / Q000276:immunology*; D018664:Interleukin-12 / Q000235:genetics / Q000276:immunology*; D051379:Mice; D018345:Mice, Knockout; D010950:Plasma Cells / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology* / Q000469:parasitology; D051193:Toll-Like Receptors / Q000276:immunology; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000235:genetics / Q000276:immunology*; D015854:Up-Regulation / Q000235:genetics / Q000276:immunology
chemical_list: D000953:Antigens, Protozoan; D000949:Histocompatibility Antigens Class II; C482903:Tlr11 protein, mouse; D051193:Toll-Like Receptors; D018664:Interleukin-12; D007371:Interferon-gamma