Krüll M, Dold C, Hippenstiel S, Rosseau S, Lohmeyer J, Suttorp N
Department of Internal Medicine, Justus-Liebig University, Giessen, Germany.
J Immunol. 1996 Nov 1;157(9):4133-40.
Adhesion of polymorphonuclear leukocytes (PMN) to endothelial cells is an essential step in inflammatory reactions. We characterized the effects of two important bacterial exotoxins, Escherichia coli hemolysin (HlyA) and Staphylococcus aureus alpha-toxin (S. alpha-toxin) on PMN adhesion to cultured HUVEC. Both toxins increased adherence of human PMN to HUVEC in a dose- and time-dependent manner, peaking after 30 min at 0.01 hemolytic units/ml HlyA or 0.5 microg/ml S. alpha-toxin. Pretreatment of HUVEC with anti-P-selectin mAbs or of PMN with anti-CD11b/CD18 mAb reduced HlyA- and S. alpha-toxin-related cell adhesion significantly. Increased P-selectin expression on toxin-treated endothelial cells was demonstrated by cell surface ELISA. Compared with endotoxin, HlyA and S. alpha-toxin did not induce the expression of E-selectin, ICAM-1, or VCAM-1. FACS analysis showed increased CD11b/CD18 expression on HlyA-, but not on S. alpha-toxin-stimulated PMN. Platelet-activating factor, an important costimulatory factor for PMN adhesion and activation, was also active in the exotoxin-stimulated adhesion system, as evidenced by studies using the platelet-activating factor receptor antagonist BN50727. HPLC analysis of endothelial cell extracts confirmed enhanced toxin-mediated PAF synthesis. The capacity of exotoxins to stimulate PMN adhesion to endothelial cells may be relevant in patients with severe local or systemic bacterial infections.
多形核白细胞（PMN）与内皮细胞的黏附是炎症反应中的一个重要步骤。我们研究了两种重要的细菌外毒素，即大肠杆菌溶血素（HlyA）和金黄色葡萄球菌α毒素（S.α毒素）对PMN黏附于培养的人脐静脉内皮细胞（HUVEC）的影响。两种毒素均以剂量和时间依赖性方式增加人PMN对HUVEC的黏附，在0.01溶血单位/毫升HlyA或0.5微克/毫升S.α毒素作用30分钟后达到峰值。用抗P选择素单克隆抗体预处理HUVEC或用抗CD11b/CD18单克隆抗体预处理PMN可显著降低与HlyA和S.α毒素相关的细胞黏附。通过细胞表面酶联免疫吸附测定法证实毒素处理的内皮细胞上P选择素表达增加。与内毒素相比，HlyA和S.α毒素未诱导E选择素、细胞间黏附分子-1（ICAM-1）或血管细胞黏附分子-1（VCAM-1）的表达。荧光激活细胞分选分析显示，HlyA刺激的PMN上CD11b/CD18表达增加，但S.α毒素刺激的PMN上未增加。血小板活化因子是PMN黏附和激活的重要共刺激因子，在毒素刺激的黏附系统中也有活性，使用血小板活化因子受体拮抗剂BN50727的研究证明了这一点。对内皮细胞提取物的高效液相色谱分析证实毒素介导的血小板活化因子合成增加。外毒素刺激PMN黏附于内皮细胞的能力可能与严重局部或全身细菌感染患者有关。
