Barnett C C, Moore E E, Mierau G W, Partrick D A, Biffl W L, Elzi D J, Silliman C C
Department of Surgery, Denver Health Medical Center and University of Colorado Health Sciences Center, Denver, Colorado 80204, USA.
Am J Physiol. 1998 Jun;274(6):C1634-44. doi: 10.1152/ajpcell.1998.274.6.C1634.
Interaction of the beta2-integrin complex on the polymorphonuclear neutrophil (PMN) with intercellular adhesion molecule-1 (ICAM-1) has been implicated in PMN-mediated cytotoxicity. This study examined interaction of the CD11a, CD11b, and CD18 subunits of the beta2-integrin with ICAM-1, transfected into Chinese hamster ovarian (CHO) cells to avoid effects of other adhesion molecules. Incubation of quiescent PMNs with wild-type and ICAM-1-transfected CHO cells produced nominal cell lysis. Similarly, when phorbol myristate acetate (PMA)-activated PMNs were incubated with wild-type CHO cells, minimal cytotoxicity was produced. However, when ICAM-1-transfected CHO cells were incubated with PMA-activated PMNs, 40% cell lysis occurred. Blockade with a monoclonal antibody (MAb) to ICAM-1 or MAbs to CD11a, CD11b, or CD18 reduced PMN-mediated cytotoxicity to baseline. To examine the role of adhesion in cytotoxicity, we studied beta2-integrin-mediated PMN adhesion to ICAM-1-transfected CHO cells and found that MAbs for CD11a, CD11b, and CD18 all abrogated PMN cytotoxicity despite disparate effects on adhesion. To assess the role of CD18, beta2-integrin subunits were cross-linked, and CD18 alone mediated protease release. Moreover, ICAM-1 was immunoprecipitated from transfected CHO cells and incubated with PMNs. This soluble ICAM-1 provoked elastase release, similar to PMA, which could be inhibited by MAbs to CD18 but not MAbs to other beta2-integrin subunits. In addition, coincubation with protease inhibitors eglin C and AAPVCK reduced PMN-mediated cytotoxicity to control levels. Finally, ICAM-1-transfected CHO cells were exposed to activated PMNs from a patient with chronic granulomatous disease that caused significant cell lysis, equivalent to that of PMNs from normal donors. Collectively, these data suggest that ICAM-1 provokes PMN-mediated cytotoxicity via CD18-mediated protease release.
多形核中性粒细胞（PMN）上的β2整合素复合物与细胞间黏附分子-1（ICAM-1）的相互作用与PMN介导的细胞毒性有关。本研究检测了β2整合素的CD11a、CD11b和CD18亚基与转染到中国仓鼠卵巢（CHO）细胞中的ICAM-1的相互作用，以避免其他黏附分子的影响。将静止的PMN与野生型和ICAM-1转染的CHO细胞孵育，产生了轻微的细胞裂解。同样，当用佛波酯肉豆蔻酸酯乙酸酯（PMA）激活的PMN与野生型CHO细胞孵育时，产生的细胞毒性最小。然而，当ICAM-1转染的CHO细胞与PMA激活的PMN孵育时，发生了40%的细胞裂解。用抗ICAM-1单克隆抗体（MAb）或抗CD11a、CD11b或CD18的MAb阻断可将PMN介导的细胞毒性降低至基线水平。为了研究黏附在细胞毒性中的作用，我们研究了β2整合素介导的PMN与ICAM-1转染的CHO细胞的黏附，发现抗CD11a、CD11b和CD18的MAb均消除了PMN细胞毒性，尽管它们对黏附的影响不同。为了评估CD18的作用，对β2整合素亚基进行交联，单独的CD18介导蛋白酶释放。此外，从转染的CHO细胞中免疫沉淀ICAM-1并与PMN孵育。这种可溶性ICAM-1引发弹性蛋白酶释放，类似于PMA，可被抗CD18的MAb抑制，但不能被抗其他β2整合素亚基的MAb抑制。此外，与蛋白酶抑制剂依吉林C和AAPVCK共同孵育可将PMN介导的细胞毒性降低至对照水平。最后，将ICAM-1转染的CHO细胞暴露于来自慢性肉芽肿病患者的激活的PMN中，导致了显著的细胞裂解，与正常供体的PMN相当。总体而言，这些数据表明ICAM-1通过CD18介导的蛋白酶释放引发PMN介导的细胞毒性。
