IL-16 is constitutively present in peripheral blood monocytes and spontaneously released during apoptosis
IL-16 is constitutively present in peripheral blood monocytes and spontaneously released during apoptosis
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DOI：
10.4049/jimmunol.172.12.7721
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发表时间：
2004-06-15
影响因子：
4.4
通讯作者：
Wewers, MD
中科院分区：
文献类型：
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作者：
Elssner, A;Doseff, AI;Wewers, MD
在T细胞、肥大细胞、嗜酸性粒细胞、上皮细胞、成纤维细胞和树突状细胞中发现了IL-16前分子的组成性表达。通过流式细胞术分析，我们发现IL-16也存在于98%的新分离的人cd14阳性外周血单核细胞中。由于前IL-16被caspase-3裂解为具有生物活性的成熟形态，而caspase-3也是单核细胞凋亡的关键效应因子，因此我们想知道IL-16释放是否发生在单核细胞自发凋亡中。正如预期的那样，新分离的、未受刺激的单核细胞自发地激活了caspase-3。这种凋亡与细胞内IL-16的丢失（流式细胞术检测）和IL-16的释放（ELISA检测）并行。相反，细菌LPS刺激抑制caspase-3的激活，并显著抑制IL-16的释放。作为特异性对照，白细胞介素1 β和白细胞介素8在单核细胞自发凋亡过程中不释放。总之，我们的数据表明单核细胞含有在自发凋亡过程中释放的IL-16。
Constitutive expression of the pro-molecule of IL-16 has been found in T cells, mast cells, eosinophils, epithelial cells, fibroblasts, and dendritic cells. Here we show that IL-16 is also constitutively present in >98% of freshly isolated human CD14-positive peripheral blood monocytes when analyzed by flow cytometry. Because pro-IL-16 is cleaved to its bioactive mature form by caspase-3, and caspase-3 is also the pivotal effector of apoptosis in monocytes, we asked whether IL-16 release occurs in monocytes that undergo spontaneous apoptosis. As expected, freshly isolated, unstimulated monocytes underwent spontaneous caspase-3 activation. This apoptosis was paralleled by the loss of intracellular IL-16, as detected by flow cytometry, and the concurrent release of IL-16, as detected by ELISA. In contrast, stimulation with bacterial LPS inhibited caspase-3 activation and significantly inhibited the release of IL-16. As a specificity control, IL-1beta and IL-8 were not released during spontaneous monocyte apoptosis. In summary, our data demonstrate that monocytes contain IL-16 that is released during spontaneous apoptosis.