Bennett T A, Schammel C M, Lynam E B, Guyer D A, Mellors A, Edwards B, Rogelj S, Sklar L A
Department of Pathology, University of New Mexico, School of Medicine, Albuquerque 87131, USA.
J Leukoc Biol. 1995 Nov;58(5):510-8. doi: 10.1002/jlb.58.5.510.
The homotypic aggregation of neutrophils requires the participation of L-selectin and the beta 2-integrins, but it has not been clear whether the two receptors recognize one another as counter-structures or whether other adhesion molecules are involved. We have examined aggregation of live neutrophils with target populations, manipulated to alter expression of adhesive epitopes, using flow cytometry. A target population depleted of both L-selectin and activatable beta 2-integrin displayed an ability to aggregate with live neutrophils, suggesting that these two molecules are not counter-structures. We also found that an O-sialoglycoprotease (GCP) from Pasteurella haemolytica is capable of inhibiting homotypic aggregation. Neutrophils treated with GCP lose O-glycosylated proteins but retain L-selectin and activatable beta 2-integrin. One or more of the GCP substrates appears to function in L-selectin-dependent binding but not in beta 2-integrin-dependent binding. Together the data suggest a mechanism of aggregation that is analogous to leukocyte-endothelial cell adhesion in which a low-affinity carbohydrate-dependent interaction precedes a high-affinity integrin-dependent adhesion.
中性粒细胞的同型聚集需要L-选择素和β2整合素的参与，但尚不清楚这两种受体是否将彼此识别为互补结构，或者是否有其他粘附分子参与其中。我们使用流式细胞术检测了活中性粒细胞与经过处理以改变粘附表位表达的靶细胞群体的聚集情况。去除了L-选择素和可激活的β2整合素的靶细胞群体表现出与活中性粒细胞聚集的能力，这表明这两种分子不是互补结构。我们还发现，溶血巴斯德菌的一种O-唾液酸糖蛋白酶（GCP）能够抑制同型聚集。用GCP处理的中性粒细胞失去了O-糖基化蛋白，但保留了L-选择素和可激活的β2整合素。GCP的一种或多种底物似乎在依赖L-选择素的结合中起作用，但在依赖β2整合素的结合中不起作用。这些数据共同提示了一种类似于白细胞-内皮细胞粘附的聚集机制，即低亲和力的碳水化合物依赖性相互作用先于高亲和力的整合素依赖性粘附。
