Kuijpers T W, Hakkert B C, Hoogerwerf M, Leeuwenberg J F, Roos D
Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam.
J Immunol. 1991 Aug 15;147(4):1369-76.
Adherence of neutrophils to endothelium is a key event in the sequence of inflammatory leukocyte responses. Double-color FACS analysis was used to determine the extent and kinetics of neutrophil adherence to rIL-1 beta-pretreated endothelial cells (EC). Neutrophils bound very avidly when the EC were prestimulated for 4 to 6 h with rIL-1 beta. Anti-ELAM-1 F(ab)2 fragments inhibited this adherence for more than 80%. On the other hand, anti-CD18 F(ab)2 fragments also inhibited the neutrophil adherence (40 to 50%). Combined use of anti-ELAM-1 and anti-CD18 F(ab)2 fragments completely prevented adherence. Neutrophils became activated as soon as they made contact with the rIL-1 beta-pretreated EC. First, neutrophils depleted of intracellular ATP showed a clearly decreased adherence completely dependent on ELAM-1-mediated binding, i.e., without additional effects of CD18 adhesion proteins. Thus, CD18 is activated during neutrophil adherence and then participates in the binding process. Secondly, the neutrophils responded with a transient rise in [Ca2+]i upon binding to rIL-1 beta-pretreated EC, which was demonstrated to be caused by endothelial cell-associated platelet-activating factor (PAF). However, the extent of neutrophil adherence to rIL-1 beta-pretreated EC was not affected by the use of the PAF-receptor antagonist WEB 2086, or removal of the EC-bound PAF. The only effect was a complete dependency of the neutrophil adherence on ELAM-1-mediated binding, although anti-CD18 mAb still induced 40 to 50% inhibition under these conditions. We therefore conclude that ELAM-1-mediated binding is the major mechanism for CD18 activation during neutrophil adherence to rIL-1 beta-pretreated EC.
中性粒细胞与内皮细胞的黏附是炎症性白细胞反应序列中的关键事件。采用双色荧光激活细胞分选术（FACS）分析来确定中性粒细胞与重组白细胞介素-1β（rIL-1β）预处理的内皮细胞（EC）黏附的程度和动力学。当EC用rIL-1β预刺激4至6小时时，中性粒细胞非常 avidly地结合。抗ELAM-1 F(ab)2片段抑制这种黏附超过80%。另一方面，抗CD18 F(ab)2片段也抑制中性粒细胞黏附（40%至50%）。联合使用抗ELAM-1和抗CD18 F(ab)2片段可完全阻止黏附。中性粒细胞一旦与rIL-1β预处理的EC接触就会被激活。首先，细胞内ATP耗尽的中性粒细胞显示出黏附明显减少，完全依赖于ELAM-1介导的结合，即没有CD18黏附蛋白的额外作用。因此，CD18在中性粒细胞黏附过程中被激活，然后参与结合过程。其次，中性粒细胞在与rIL-1β预处理的EC结合后，细胞内钙离子浓度（[Ca2+]i）出现短暂升高，这被证明是由内皮细胞相关的血小板活化因子（PAF）引起的。然而，中性粒细胞与rIL-1β预处理的EC的黏附程度不受PAF受体拮抗剂WEB 2086的使用或去除EC结合的PAF的影响。唯一的影响是中性粒细胞黏附完全依赖于ELAM-1介导的结合，尽管在这些条件下抗CD18单克隆抗体仍诱导40%至50%的抑制。因此，我们得出结论，ELAM-1介导的结合是中性粒细胞黏附于rIL-1β预处理的EC过程中CD18激活的主要机制。
