Richter J, Ng-Sikorski J, Olsson I, Andersson T
Department of Medicine, University Hospital, Lund, Sweden.
Proc Natl Acad Sci U S A. 1990 Dec;87(23):9472-6. doi: 10.1073/pnas.87.23.9472.
We have recently been able to correlate closely the "spontaneous" oscillatory activity of cytosolic free Ca2+ in adherent human neutrophils with the ability of tumor necrosis factor (TNF) to induce secretion of granule proteins from these cells. In the present work we show with a single-cell technique that preincubation of human neutrophils with antibodies to CD18, the common beta chain of leukocyte adhesion proteins, inhibits TNF-induced secretion of lactoferrin in a time- and concentration-dependent manner. Similar effects of CD18 antibodies were found on chemotactic factor (fMet-Leu-Phe)- but not on phorbol 12-myristate 13-acetate-induced secretion, suggesting that cell-surface-receptor-mediated secretion is dependent on integrin-associated signals. Similarly, antibodies to CD11b (alpha chain of macrophage 1) also inhibited TNF- and fMet-Leu-Phe- but not phorbol 12-myristate 13-acetate-stimulated release of lactoferrin. Antibodies to CD11a (alpha chain of lymphocyte function-associated antigen 1) or CD11c (alpha chain of p150,95) had only a minimal effect on agonist-induced secretion. Data obtained in several laboratories, including our own, made us suspect that integrin interaction with the surface is responsible for the oscillatory activity of cytosolic free Ca2+ in adherent cells. Indeed, preincubation with antibodies to either CD18 or CD11b, but not to CD11c, inhibited the oscillations of cytosolic free Ca2+ in adherent neutrophils. This inhibitory effect was evident both as a reduction of the number of responding cells and as a reduction of the oscillatory activity in the cells. In conclusion, the oscillatory activity of cytosolic free Ca2+ in adherent neutrophils is mediated through the CD18/CD11b integrins. The generation of this Ca2+ signal may explain how adherence, by way of the integrins, changes the functional properties of the cell and enables TNF to induce secretion.
我们最近已能够将贴壁人中性粒细胞中胞质游离Ca2+的“自发”振荡活性与肿瘤坏死因子（TNF）诱导这些细胞分泌颗粒蛋白的能力紧密关联起来。在本研究中，我们采用单细胞技术表明，用针对白细胞黏附蛋白共同β链CD18的抗体对人中性粒细胞进行预孵育，会以时间和浓度依赖性方式抑制TNF诱导的乳铁蛋白分泌。在趋化因子（fMet-Leu-Phe）诱导的分泌方面发现了CD18抗体的类似作用，但在佛波酯12-肉豆蔻酸酯13-乙酸酯诱导的分泌方面未发现类似作用，这表明细胞表面受体介导的分泌依赖于整合素相关信号。同样，针对CD11b（巨噬细胞1的α链）的抗体也抑制TNF和fMet-Leu-Phe诱导的乳铁蛋白释放，但不抑制佛波酯12-肉豆蔻酸酯13-乙酸酯刺激的释放。针对CD11a（淋巴细胞功能相关抗原1的α链）或CD11c（p150,95的α链）的抗体对激动剂诱导的分泌仅有极小的影响。包括我们自己实验室在内的几个实验室获得的数据使我们怀疑整合素与表面的相互作用是贴壁细胞中胞质游离Ca2+振荡活性的原因。事实上，用针对CD18或CD11b而非CD11c的抗体进行预孵育，会抑制贴壁中性粒细胞中胞质游离Ca2+的振荡。这种抑制作用在反应细胞数量减少以及细胞中振荡活性降低两方面都很明显。总之，贴壁中性粒细胞中胞质游离Ca2+的振荡活性是通过CD18/CD11b整合素介导的。这种Ca2+信号的产生可能解释了整合素介导的黏附如何改变细胞的功能特性并使TNF能够诱导分泌。
