Essential role of the C5a receptor in E coli-induced oxidative burst and phagocytosis revealed by a novel lepirudin-based human whole blood model of inflammation.
Essential role of the C5a receptor in E coli-induced oxidative burst and phagocytosis revealed by a novel lepirudin-based human whole blood model of inflammation.
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DOI：
10.1182/blood.v100.5.1869.h81702001869_1869_1877
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发表时间：
2002-09
期刊：
影响因子：
20.3
通讯作者：
T. Mollnes;O. Brekke;M. Fung;H. Fure;D. Christiansen;G. Bergseth;V. Videm;K. Lappegård;J. Köhl;John D Lambris
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文献类型：
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作者：
T. Mollnes;O. Brekke;M. Fung;H. Fure;D. Christiansen;G. Bergseth;V. Videm;K. Lappegård;J. Köhl;John D Lambris
补体在炎症和组织损伤中起重要作用。然而，在多大程度上该系统在人全血的炎症网络中充当次级介质系统的主要诱导物在很大程度上是未知的。在这里，我们描述了一种新的体外模型，使用凝血酶特异性水蛭素类似物来匹卢定作为抗凝剂，与肝素相比，不干扰补体激活。该模型用于研究补体在大肠杆菌诱导的炎症反应中的作用。粒细胞和单核细胞的氧化爆发是补体依赖性的，因为它分别被C3 [校正]结合肽坎普他汀降低了85%和70%。通过抑制C5、C5 a和C5 a受体（C5 aR）也发现了类似的减少。此外，抗CR 3抗体在减少粒细胞氧化爆发方面与C5 aR拮抗剂一样有效，而阻断CD 14或C3 aR则没有效果。C5 aR拮抗剂几乎消除了粒细胞CR 3的上调。通过阻断C5 aR或CR 3完全抑制调理作用和吞噬作用，而阻断Fc γ R（CD 16、CD 32、CD 64）没有影响。与氧化爆发和吞噬作用相反，细胞因子分泌在很大程度上不依赖于补体。因此，抗CD 14消除了肿瘤坏死因子-α、白细胞介素-6（IL-6）和IL-10的分泌，而IL-8同样受到抗CD 14和坎普他汀的抑制。总之，本模型对于研究补体作为炎症网络的一部分特别有用。这些结果强调了C5 a-C5 aR相互作用在大肠杆菌诱导的CR 3上调以及随后的氧化爆发和吞噬作用中的关键作用。补体抑制可能在氧化爆发诱导的组织损伤中具有治疗意义。
Complement plays an essential role in inflammation and tissue damage. However, it is largely unknown to what extent the system acts as a primary inducer of secondary mediator systems in the inflammatory network of human whole blood. Here we describe a novel in vitro model using the thrombin-specific hirudin analog lepirudin as anticoagulant, which, in contrast to heparin, did not interfere with complement activation. The model was used to study the role of complement in Escherichia coli-induced inflammatory responses. Granulocyte and monocyte oxidative burst was complement dependent as it was reduced by 85% and 70%, respectively, by the C3 [corrected] binding peptide compstatin. A similar reduction was found by inhibition of C5, C5a, and C5a receptor (C5aR). Furthermore, anti-CR3 antibodies were as efficient as the C5aR antagonist in reducing granulocyte oxidative burst, whereas blocking CD14 or C3aR had no effect. Up-regulation of granulocyte CR3 was virtually abolished by a C5aR antagonist. Opsonization and phagocytosis was completely inhibited by blocking of C5aR or CR3, whereas blocking of the FcgammaRs (CD16, CD32, CD64) had no effect. In contrast to oxidative burst and phagocytosis, cytokine secretion was largely complement independent. Thus, anti-CD14 abolished tumor necrosis factor-alpha, interleukin-6 (IL-6), and IL-10 secretion, whereas IL-8 was equally inhibited by anti-CD14 and compstatin. In conclusion, the present model is particularly useful for studying complement as part of the inflammatory network. The results emphasize a crucial role for C5a-C5aR interaction in E coli-induced up-regulation of CR3 and the subsequent oxidative burst and phagocytosis. Complement inhibition may have therapeutic implications in oxidative burst-induced tissue damage.