Nagayama H, Sato K, Kawasaki H, Enomoto M, Morimoto C, Tadokoro K, Juji T, Asano S, Takahashi T A
Departments of Cell Processing, Clinical Immunology and AIDS Research Center, and Hematology/Oncology, Institute of Medical Science, University of Tokyo, Japan.
J Immunol. 2000 Jul 1;165(1):59-66. doi: 10.4049/jimmunol.165.1.59.
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.
我们分析了IL-12Rβ1和IL-12Rβ2的表达，以及IL-12通过IL-12Rβ1介导的信号转导事件在单核细胞衍生树突状细胞（DCs）激活中的作用。流式细胞术分析显示，IL-12Rβ1在T细胞、刀豆蛋白A刺激的母细胞和单核细胞衍生的DCs中表达，但在单核细胞中不表达，而在所有这些细胞类型中均检测到其转录本。在T细胞、刀豆蛋白A刺激的母细胞和单核细胞衍生的DCs中观察到IL-12Rβ2的转录表达，但在单核细胞中未观察到。IL-12对DCs以及刀豆蛋白A刺激的母细胞的连接在转录水平上诱导了GM-CSF、IL-1β、IL-6、TNF-α和IFN-γ的产生。此外，用IL-12刺激DCs诱导了IL-1[sub]2[/sub]p40转录本，但未诱导IL-12p35转录本，而这种刺激在刀豆蛋白A刺激的母细胞中导致了两种转录本的表达。用IL-12刺激DCs导致几种细胞内蛋白的酪氨酸磷酸化，这些事件的模式与IL-12刺激的刀豆蛋白A刺激的母细胞不同。IL-12还诱导了IL-12Rβ1的酪氨酸磷酸化以及几种酪氨酸磷酸化蛋白在DCs和刀豆蛋白A刺激的母细胞中向IL-12Rβ1的募集。IL-12对DCs以及刀豆蛋白A刺激的母细胞的受体结合导致了Janus激酶2和Tyk2激酶以及Stat3和Stat4转录因子的激活，以及这些蛋白与IL-12Rβ1的结合。用IL-12刺激导致了丝裂原活化蛋白激酶家族p38mapk的酪氨酸磷酸化和酶活性。这些结果表明，IL-12通过IL-12Rβ1介导的信号转导事件直接作用于DCs以诱导其功能激活。
