title: Kinetics of dendritic cell activation: impact on priming of TH1, TH2 and nonpolarized T cells.
abstract: To prime immune responses, dendritic cells (DCs) need to be activated to acquire T cell stimulatory capacity. Although some stimuli trigger interleukin 12 (IL-12) production that leads to T helper cell type I (TH1) polarization, others fail to do so and favor TH2 polarization. We show that after activation by lipopolysaccharide, DCs produced IL-12 only transiently and became refractory to further stimulation. The exhaustion of cytokine production impacted the T cell polarizing process. Soon after stimulation DCs primed strong TH1 responses, whereas at later time points the same cells preferentially primed TH2 and nonpolarized T cells. These findings indicate that during an immune response, T cell priming conditions may change in the lymph nodes, suggesting another mechanism for the regulation of effector and memory T cells.
authors.affiliation: Institute for Research in Biomedicine, Via Vincenzo Vela 6, CH-6500 Bellinzona, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Langenkamp
authors.forename: M
authors.initials: M
authors.lastname: Messi
authors.forename: A
authors.initials: A
authors.lastname: Lanzavecchia
authors.forename: F
authors.initials: F
authors.lastname: Sallusto
mesh_terms: D002454:Cell Differentiation / Q000276:immunology; D016764:Cell Polarity / Q000276:immunology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D006801:Humans; D007156:Immunologic Memory; D018664:Interleukin-12 / Q000276:immunology*; D008213:Lymphocyte Activation; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D018664:Interleukin-12