Chignard M, Hazouard E, Renesto P, Laine A, Guidet B, Offenstadt G
Unité de Pharmacologie Cellulaire, Unité Associée IP/INSERM no. 285, Institut Pasteur, Paris, France.
Biochim Biophys Acta. 1994 Dec 30;1224(3):433-40. doi: 10.1016/0167-4889(94)90279-8.
Upon activation, human polymorphonuclear neutrophils (PMN) release two serine proteinases, cathepsin G (Cat.G) and elastase (HLE), which in turn synergize to activate nearby platelets. We looked for the inhibitory effect of plasma and the involvement of alpha 1 antichymotrypsin (alpha 1 ACT) and alpha 1 antitrypsin (alpha 1 AT), on this cell-to-cell cooperation. It was observed that inhibition by plasma of PMN-mediated platelet activation was rather correlated with an effect on HLE (r = 0.95) than on Cat.G (r = 0.65) enzymatic activity. Purified alpha 1 AT suppressed in a concentration-dependent manner HLE activity present in the supernatant of activated PMN. When HLE was fully blocked, alpha 1 AT started to inhibit Cat.G activity. By contrast and as expected, purified alpha 1 ACT inhibited only Cat.G activity. Using specific blocking polyclonal antibodies against alpha 1 AT and alpha 1 ACT, it was demonstrated that the inhibitory effect of plasma vs. HLE was entirely mediated by alpha 1 AT. By contrast, blockade of Cat.G activity was only partly due to plasma alpha 1 ACT and around 50% was attributable to alpha 1 AT. When plasma from patients with an acute inflammatory state was used in place of plasma from normal subjects, the inhibitory effect was more pronounced, while plasma depleted in alpha 1 AT and alpha 1 ACT was less effective. These data indicate a predominant role of alpha 1 AT in the inhibition by plasma of the PMN-mediated platelet activation.
激活后，人类多形核中性粒细胞（PMN）会释放两种丝氨酸蛋白酶，即组织蛋白酶G（Cat.G）和弹性蛋白酶（HLE），这两种酶又会协同激活附近的血小板。我们研究了血浆的抑制作用以及α1抗糜蛋白酶（α1ACT）和α1抗胰蛋白酶（α1AT）在这种细胞间协作中的作用。结果发现，血浆对PMN介导的血小板激活的抑制作用与对HLE酶活性的影响（r = 0.95）的相关性，高于对Cat.G酶活性的影响（r = 0.65）。纯化的α1AT以浓度依赖的方式抑制活化PMN上清液中的HLE活性。当HLE被完全阻断时，α1AT开始抑制Cat.G活性。相比之下，正如预期的那样，纯化的α1ACT仅抑制Cat.G活性。使用针对α1AT和α1ACT的特异性阻断多克隆抗体，证明血浆对HLE的抑制作用完全由α1AT介导。相比之下，Cat.G活性的阻断仅部分归因于血浆α1ACT，约50%归因于α1AT。当使用急性炎症状态患者的血浆代替正常受试者的血浆时，抑制作用更明显，而α1AT和α1ACT耗尽的血浆效果较差。这些数据表明α1AT在血浆对PMN介导的血小板激活的抑制中起主要作用。
