Grimminger F, Hattar K, Papavassilis C, Temmesfeld B, Csernok E, Gross W L, Seeger W, Sibelius U
Department of Internal Medicine, Justus-Liebig-University, Giessen, Germany.
J Exp Med. 1996 Oct 1;184(4):1567-72. doi: 10.1084/jem.184.4.1567.
Among the anti-neutrophil cytoplasmic antibodies (ANCA), those targeting proteinase 3 (PR3) have a high specificity for Wegener's granulomatosis (WG). It is known that a preceding priming of neutrophils with cytokines is a prerequisite for membrane surface expression of PR3, which is then accessible to autoantibody binding. Employing a monoclonal antibody directed against human PR3 and ANCA-positive serum from WG patients with specificity for PR3, we now investigated the role of free arachidonic acid (AA) in autoantibody-related human neutrophil activation. Priming of neutrophils with tumor necrosis factor (TNF-alpha) for 15 min or exposure to anti-PR3 antibodies or incubation with free AA (10 microM) as sole events did not provoke superoxide generation, elastase secretion or generation of 5-lipoxygenase products of AA. Similarly, the combination of TNF-alpha-priming and AA incubation was ineffective. When TNF-alpha-primed neutrophils were stimulated by anti-PR3 antibodies, superoxide and elastase secretion was provoked in the absence of lipid mediator generation. However, when free AA was additionally provided, a strong activation of the 5-lipoxygenase pathway was demasked, with the appearance of excessive quantities of leukotriene (LT)B4, LTA4, and 5-hydroxyeicosatetraenoic acid. Moreover, superoxide and elastase secretion were markedly amplified, and studies with 5-lipoxygenase inhibitors and a LTB4-antagonist demonstrated this was due to an LTB4-related autocrine loop of cell activation. In contrast, the increased synthesis of platelet-activating factor in response to TNF-alpha-priming and anti-PR3 stimulation did not contribute to the amplification loop of neutrophil activation under the given conditions. We conclude that anti-PR3 antibodies are potent inductors of the 5-lipoxygenase pathway in primed human neutrophils, and extracellular free AA, as provided at an inflammatory focus, synergizes with the autoantibodies to evoke full-blown lipid mediator generation, granule secretion and respiratory burst. Such events may be enrolled in the pathogenesis of focal necrotizing vascular injury in Wegener's granulomatosis.
在抗中性粒细胞胞浆抗体（ANCA）中，那些靶向蛋白酶3（PR3）的抗体对韦格纳肉芽肿（WG）具有高度特异性。已知用细胞因子预先刺激中性粒细胞是PR3在膜表面表达的先决条件，随后PR3可被自身抗体结合。我们使用一种针对人PR3的单克隆抗体和来自对PR3具有特异性的WG患者的ANCA阳性血清，研究了游离花生四烯酸（AA）在自身抗体相关的人中性粒细胞活化中的作用。单独用肿瘤坏死因子（TNF-α）刺激中性粒细胞15分钟、暴露于抗PR3抗体或与游离AA（10微摩尔）孵育，均未引发超氧化物生成、弹性蛋白酶分泌或AA的5-脂氧合酶产物生成。同样，TNF-α刺激和AA孵育的组合也无效。当用抗PR3抗体刺激经TNF-α刺激的中性粒细胞时，在没有脂质介质生成的情况下引发了超氧化物和弹性蛋白酶分泌。然而，当额外提供游离AA时，5-脂氧合酶途径被强烈激活，出现了过量的白三烯（LT）B4、LTA4和5-羟基二十碳四烯酸。此外，超氧化物和弹性蛋白酶分泌明显增强，用5-脂氧合酶抑制剂和LTB4拮抗剂进行研究表明这是由于细胞活化的LTB4相关自分泌环所致。相比之下，在给定条件下，TNF-α刺激和抗PR3刺激引起的血小板活化因子合成增加对中性粒细胞活化的放大环没有贡献。我们得出结论，抗PR3抗体是已致敏的人中性粒细胞中5-脂氧合酶途径的有效诱导剂，炎症部位提供的细胞外游离AA与自身抗体协同作用，引发全面的脂质介质生成、颗粒分泌和呼吸爆发。这些事件可能参与了韦格纳肉芽肿局灶性坏死性血管损伤的发病机制。
