Receptor cross-linking on human plasmacytoid dendritic cells leads to the regulation of IFN-α production
Receptor cross-linking on human plasmacytoid dendritic cells leads to the regulation of IFN-α production
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DOI：
10.4049/jimmunol.177.9.5829
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发表时间：
2006-11-01
影响因子：
4.4
通讯作者：
Fitzgerald-Bocarsly, Patricia
中科院分区：
文献类型：
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作者：
Fanning, Stacey L.;George, Thaddeus C.;Fitzgerald-Bocarsly, Patricia
浆细胞样树突状细胞(PDC)是天然的I型干扰素产生细胞，能在病毒刺激下产生大量的干扰素-α。在从人外周血单核细胞中分离PDC的过程中，我们观察到多种细胞表面受体，包括血DC抗原(BDCA)-2、BDCA-4、CD4或CD123与抗体和PDC上的免疫小球交联会导致对HSV反应产生的干扰素-α的抑制。为了了解所涉及的机制，对一些参数进行了研究。交联剂不能抑制PDC对可溶性Ag的内吞作用。流式细胞仪检测Annexin V和活化的caspase-3表明，受体交联后，PDC没有发生凋亡。共刺激分子CD80和CD86表达上调，CD62L表达下调，提示PDC成熟。因此，抗CD123抗体的作用可能类似于天然配体IL-3。用抗磷酸酪氨酸抗体和干扰素调节因子IRF-7抗体进行细胞内流式细胞术，以阐明相关的信号通路。BDCA-2和BDCA-4交联后，酪氨酸磷酸化发生，但不是CD4。交联剂不影响PDC中IRF-7的水平，但交联剂BDCA-2、BDCA-4和CD4，但不影响CD123，可抑制IRF-7转位到细胞核的能力。综上所述，这些结果表明，PDC上BDCA-2、BDCA-4和CD4的交联物在IRF-7水平上调节干扰素-α的产生，而CD123交联物后干扰素-α的产生减少是由于刺激IL-3R和诱导PDC成熟。
Plasmacytoid dendritic cells (PDC) are the natural type I IFN-producing cells that produce large amounts of IFN-alpha in response to viral stimulation. During attempts to isolate PDC from human PBMC, we observed that cross-linking a variety of cell surface receptors, including blood DC Ag (BDCA)-2, BDCA-4, CD4, or CD123 with Abs and immunobeads on PDC leads to inhibition of IFN-alpha production in response to HSV. To understand the mechanisms involved, a number of parameters were investigated. Cross-linking did not inhibit endocytosis of soluble Ag by PDC. Flow cytometry for annexin V and activated caspase-3 indicated that PDC are not undergoing apoptosis after receptor cross-linking. Cross-linking of CD123, but not the other receptors, caused the up-regulation of costimulatory molecules CD80 and CD86, as well as the down-regulation of CD62L, indicating PDC maturation. Thus, anti-CD123 Ab may be acting similar to the natural ligand, IL-3. Anti-phosphotyrosine Ab, as well as Ab to the IFN regulatory factor, IRF-7, was used in intracellular flow cytometry to elucidate the signaling pathways involved. Tyrosine phosphorylation occurred after cross-linking BDCA-2 and BDCA-4, but not CD4. Cross-linking did not affect IRF-7 levels in PDC, however, cross-linking BDCA-2, BDCA-4, and CD4, but not CD123, inhibited the ability of IRF-7 to translocate to the nucleus. Taken together, these results suggest that cross-linking BDCA-2, BDCA-4, and CD4 on PDC regulates IFN-a production at the level of IRF-7, while the decrease in IFN-alpha production after CD123 cross-linking is due to stimulation of the IL-3R and induction of PDC maturation.