title: IL-12 responsiveness and expression of IL-12 receptor in human peripheral blood monocyte-derived dendritic cells.
abstract: We analyzed the expression of IL-12Rbeta1 and IL-12Rbeta2 and the role of IL-12 in the activation of monocyte-derived dendritic cells (DCs) via IL-12Rbeta1-mediated signaling events. Flow cytometric analysis revealed that IL-12Rbeta1 was expressed in T cells, Con A blasts, and monocyte-derived DCs, but not in monocytes, while its transcript was detected in all of these cell types. Transcriptional expression of IL-12Rbeta2 was observed in T cells, Con A blasts, and monocyte-derived DCs, but not monocytes. The ligation of DCs as well as Con A blasts by IL-12 induced the production of GM-CSF, IL-1beta, IL-6, TNF-alpha, and IFN-gamma at the transcription levels. Furthermore, stimulation of DCs with IL-12 induced IL-12p40 transcript, but not IL-12p35 transcript, whereas this stimulation caused the expressions of both transcripts in Con A blasts. Stimulation of DCs with IL-12 caused a tyrosine phosphorylation of several intracellular proteins, and the pattern of these events were distinct from those of IL-12-stimulated Con A blasts. IL-12 also induced tyrosine phosphorylation of IL-12Rbeta1 as well as recruitment of several tyrosine-phosphorylated proteins to IL-12Rbeta1 in DCs and Con A blasts. Receptor engagement of DCs as well as Con A blasts by IL-12 resulted in activation of Janus kinase 2 and Tyk2 kinases and Stat3 and Stat4 transcription factors and the association of these proteins to IL-12Rbeta1. Stimulation with IL-12 caused a tyrosine phosphorylation and enzymatic activity of a family of mitogen-activated protein kinases, p38mapk. These results suggest that IL-12 acts directly on DCs to induce their functional activation via IL-12Rbeta1-mediated signaling events.
authors.affiliation: Departments of Cell Processing, Clinical Immunology and AIDS Research Center, and Hematology/Oncology, Institute of Medical Science, University of Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nagayama
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Kawasaki
authors.forename: M
authors.initials: M
authors.lastname: Enomoto
authors.forename: C
authors.initials: C
authors.lastname: Morimoto
authors.forename: K
authors.initials: K
authors.lastname: Tadokoro
authors.forename: T
authors.initials: T
authors.lastname: Juji
authors.forename: S
authors.initials: S
authors.lastname: Asano
authors.forename: T A
authors.initials: TA
authors.lastname: Takahashi
mesh_terms: D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D016207:Cytokines / Q000096:biosynthesis; D004268:DNA-Binding Proteins / Q000378:metabolism; D003713:Dendritic Cells / Q000201:enzymology / Q000276:immunology* / Q000378:metabolism*; D004789:Enzyme Activation / Q000276:immunology; D006801:Humans; D018664:Interleukin-12 / Q000097:blood / Q000502:physiology*; D007424:Intracellular Fluid / Q000378:metabolism; D053614:Janus Kinase 2; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D018123:Receptors, Interleukin / Q000096:biosynthesis* / Q000097:blood / Q000502:physiology; D053707:Receptors, Interleukin-12; D050796:STAT3 Transcription Factor; D050797:STAT4 Transcription Factor; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D053634:TYK2 Kinase; D015534:Trans-Activators / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D016207:Cytokines; D004268:DNA-Binding Proteins; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D050797:STAT4 Transcription Factor; C494090:STAT4 protein, human; D015534:Trans-Activators; D003208:Concanavalin A; D018664:Interleukin-12; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D053634:TYK2 Kinase; C070139:TYK2 protein, human; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases