Shear and time-dependent changes in Mac-1, LFA-1, and ICAM-3 binding regulate neutrophil homotypic adhesion
Shear and time-dependent changes in Mac-1, LFA-1, and ICAM-3 binding regulate neutrophil homotypic adhesion
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DOI：
10.4049/jimmunol.164.7.3798
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发表时间：
2000-04-01
影响因子：
4.4
通讯作者：
Simon, SI
中科院分区：
文献类型：
--
作者：
Neelamegham, S;Taylor, AD;Simon, SI
我们检测了LFA-1、Mac-1和ICAM-3在剪切速率为100 ~ 800 s（-1）的甲酰肽刺激下对同型中性粒细胞粘附的相对贡献。分离的人中性粒细胞在锥板粘度计中剪切，并通过流式细胞术测量聚集体形成的动力学，通过用基于两体碰撞理论的模型拟合聚集体形成速率来计算细胞粘附效率。中性粒细胞同型粘附动力学随剪切速率而变化，在800 s（-1）时最有效，其中约40%的碰撞导致粘附。加入一组针对LFA-1、Mac-1和ICAM-3的阻断Ab，以评估这些分子的相对贡献。我们报告1）LFA-1结合ICAM-3作为其支持同型粘附的主要配体，尽管也检测到其他配体的可能性。2)Mac-1与一种未鉴定的配体结合，在类似于100 s（-1）的低剪切速率下支持同型粘附，其效率与LFA-1相当。然而，在300 s（-1）以上，Mac-1而不是LFA-1是支持细胞粘附的主要分子。这与嗜中性粒细胞粘附于ICAM-1转染的细胞形成对比，其中LFA-1以比Mac-1更高的亲合力结合于ICAM-1。3）在刺激后，LFA-1支持聚集体形成的能力以比Mac-1快3倍的速率随时间降低。结果表明，β（2）整合素和ICAM-3对中性粒细胞粘附的相对贡献受微静脉微循环典型血流条件范围内流体剪切力大小和刺激时间的调节。
We examined the relative contributions of LFA-1, Mac-1, and ICAM-3 to homotypic neutrophil adhesion over the time course of formyl peptide stimulation at shear rates ranging from 100 to 800 s(-1). Isolated human neutrophils were sheared in a cone-plate viscometer and the kinetics of aggregate formation was measured by flow cytometry, The efficiency of cell adhesion was computed by fitting the aggregate formation rates with a model based on two-body collision theory. Neutrophil homotypic adhesion kinetics varied with shear rate and was most efficient at 800 s(-1), where similar to 40% of the collisions resulted in adhesion. A panel of blocking Abs to LFA-1, Mac-1, and ICAM-3 was added to assess the relative contributions of these molecules. We report that 1) LFA-1 binds ICAM-3 as its primary ligand supporting homotypic adhesion, although the possibility of other ligands was also detected. 2) Mac-1 binding to an unidentified ligand supports homotypic adhesion with an efficiency comparable to LFA-1 at low shear rates of similar to 100 s(-1). Above 300 s(-1), however, Mac-1 and not LFA-1 were the predominant molecules supporting cell adhesion. This is in contrast to neutrophil adhesion to ICAM-1-transfected cells, where LFA-1 binds with a higher avidity than Mac-1 to ICAM-1, 3) Following stimulation, the capacity of LFA-1 to support aggregate formation decreases with time at a rate similar to 3-fold faster than that of Mac-1. The results suggest that the relative contributions of beta(2) integrins and ICAM-3 to neutrophil adhesion is regulated by the magnitude of fluid shear and time of stimulus over a range of blood flow conditions typical of the venular microcirculation.