Up-regulation of the iC3b receptor (CR3) is neither necessary nor sufficient to promote neutrophil aggregation.
Up-regulation of the iC3b receptor (CR3) is neither necessary nor sufficient to promote neutrophil aggregation.
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iC3b 受体 (CR3) 的上调对于促进中性粒细胞聚集既不是必要的也不是充分的。
DOI：
10.1172/jci113623
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Abramson,SB
中科院分区：
文献类型：
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作者：
Philips,MR;Buyon,JP;Winchester,R;Weissmann,G;Abramson,SB
IC3b受体(CR3)是中性粒细胞黏附功能所必需的，包括同型聚集。因为促进中性粒细胞黏附的刺激也会诱导表面CR3的上调，所以人们普遍认为这两种反应是有因果关系的。我们已经将CR3展示(免疫荧光)与CR3功能(聚集)分离。中性粒细胞在4摄氏度分离并重新升温至37摄氏度时，表面CR3上调了一倍，但没有聚集。FMLP诱导的CR3上调动力学与聚集动力学不一致。在没有细胞外二价阳离子的情况下，暴露于FMLP后，CR3的表达增加了两倍，但中性粒细胞没有聚集。FMLP诱导的聚集是离子载体A23187的3.5倍，但不到CR3上调的一半。3 mM水杨酸钠可抑制55+/-4%的聚集，但不影响CR3的上调。相反，1 mM丁卡因完全抑制CR3的上调，同时显著促进聚集。中性粒细胞表达CR3，但不上调受体；相反，FMLP诱导依赖CR3的中性粒细胞聚集。我们的结论是，尽管构成表面的CR3是中性粒细胞聚集所必需的，但CR3的上调既不是必要的，也不足以促进细胞间的黏附。
The iC3b receptor (CR3) is required for neutrophil adhesive functions, including homotypic aggregation. Because stimuli that enhance neutrophil adhesion also induce up-regulation of surface CR3, it is widely held that these two responses are causally related. We have dissociated CR3 display (immunofluorescence) from CR3 function (aggregation). Neutrophils isolated at 4 degrees C and rewarmed to 37 degrees C up-regulated surface CR3 twofold, but did not aggregate. The kinetics of FMLP-induced CR3 up-regulation were discordant with those of aggregation. In the absence of extracellular divalent cations, CR3 expression increased twofold after exposure to FMLP, but neutrophils did not aggregate. FMLP elicited 3.5-fold more aggregation than the ionophore A23187, yet less than one-half as much CR3 up-regulation. 3 mM sodium salicylate inhibited aggregation 55 +/- 4%, but had no effect on CR3 up-regulation. Conversely, 1 mM tetracaine completely inhibited CR3 up-regulation, while significantly enhancing aggregation. Neutroplasts expressed CR3, but did not up-regulate the receptor; in contrast, FMLP induced CR3-dependent aggregation of neutroplasts. We conclude that, although constitutive surface CR3 is required for neutrophil aggregation, the up-regulation of CR3 is neither necessary nor sufficient to promote cell-cell adhesion.Images