CD19 controls Toll-like receptor 9 responses in human B cells.
CD19 controls Toll-like receptor 9 responses in human B cells.
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DOI：
10.1016/j.jaci.2015.08.040
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
Meffre E
中科院分区：
文献类型：
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作者：
Morbach H;Schickel JN;Cunningham-Rundles C;Conley ME;Reisli I;Franco JL;Meffre E
CD 19是B细胞特异性分子，其充当用于扩增B细胞受体（BCR）应答的主要共刺激分子。双等位基因CD 19基因突变导致人类常见变异型免疫缺陷（CVID）。BCR和TLR 9诱导的B细胞应答在大多数CVID患者中受损。我们试图分析在人B细胞中TLR 9功能是否需要CD 19。在抗IgM或CpG刺激后，使用流式细胞术对来自具有一个或两个缺陷型CD 19等位基因（其分别降低或消除CD 19表达）的患者的B细胞评估表面活化标志物的表达。在CD 19缺陷或对照B细胞中以及在其中CD 19已经使用慢病毒转导的shRNA敲低的B细胞系中，使用磷酸化流式细胞术、免疫印迹或免疫共沉淀来分析信号分子的磷酸化或相互作用。来自具有一个或两个缺陷性CD 19等位基因的个体的B细胞在TLR 9刺激后显示出CD 86、TACI和CD 23活化标志物的体外缺陷性上调。TLR 9配体通常通过MYD 88/PYK 2/林恩复合物诱导CD 19的磷酸化，这允许在人B细胞中以与BCR不同的动力学募集PI 3 K以及BTK和AKT的磷酸化。此外，PI 3 K、AKT或BTK的抑制以及BTK缺陷也导致B细胞中的TLR 9活化缺陷，类似于CD 19缺陷中的TLR 9活化缺陷。结论：CD 19是TLR 9诱导B细胞活化所必需的。因此，CD 19/PI 3 K/AKT/BTK是整合人B细胞中BCR和TLR 9信号传导的必需轴。
CD19 is a B-cell specific molecule that serves as a major co-stimulatory molecule for amplifying B cell receptor (BCR) responses. Bi-allelic CD19 gene mutations cause common variable immunodeficiency (CVID) in humans. BCR and TLR9 induced B-cell responses are impaired in most CVID patients. We sought to analyze whether CD19 is required for TLR9 function in human B cells. The expression of surface activation markers was assessed after anti-IgM or CpG stimulation using flow cytometry on B cells from patients with one or two defective CD19 alleles, which decrease or abrogate CD19 expression, respectively. The phosphorylation or interaction of signaling molecules was analyzed using phosphoflow cytometry, immunoblot or co-immunoprecipitation in CD19-deficient or control B cells and in a B cell line in which CD19 has been knocked-down using lentiviral transduced shRNA. B cells from individuals with one or two defective CD19 alleles showed defective upregulation in vitro of CD86, TACI and CD23 activation markers after TLR9 stimulation. TLR9 ligands normally induce via MYD88/PYK2/LYN complexes the phosphorylation of CD19, which allows the recruitment of PI3K and the phosphorylation of BTK and AKT in human B cells with a different kinetic than that of BCRs. In addition, inhibition of PI3K, AKT or BTK as well as BTK-deficiency also result in TLR9 activation defects in B cells similar to those in CD19 deficiency. Conclusion: CD19 is required for TLR9-induced B-cell activation. Hence, CD19/PI3K/AKT/BTK is an essential axis integrating BCRs and TLR9 signaling in human B cells.