Rochon Y P, Simon S I, Lynam E B, Sklar L A
University of New Mexico Cancer Center, Albuquerque 87131.
J Immunol. 1994 Feb 1;152(3):1385-93.
We have recently reported that neutrophil aggregation is dependent on both L-selectin and the beta 2-integrin Mac-1, raising the possibility that carbohydrate interactions play a role in aggregation. We used mono- and polysaccharides known to inhibit L-selectin-dependent adhesion of lymphocytes to high endothelial venules to test whether these carbohydrates could inhibit neutrophil aggregation. Similar types and concentrations of carbohydrates found by others to inhibit lymphocyte adhesion were effective in blocking neutrophil aggregation. Thus, nanomolar concentrations of the polysaccharides dextran sulfate (m.w. 500,000) and fucoidan inhibited aggregation, whereas dermatan sulfate, alpha-carrageenan, and dextran sulfate (m.w. 5,000) showed no inhibition. All of the phosphorylated monosaccharides tested inhibited aggregation with ED50 values between 8 and 17 mM, the most potent being mannose-6-phosphate and fucose-1-phosphate. The nonphosphorylated monosaccharides glucose and fucose were noninhibitory. The inhibitory effects of fucoidan or dextran sulfate (m.w. 500,000) did not appear to be due to altered regulation of L-selectin after stimulation because fucoidan reduced the rate of L-selectin shedding, whereas dextran sulfate had no effect compared with control. Neither carbohydrate inhibited the binding of formyl peptide to its receptor. However, carbohydrates were able to compete with mAb binding to a number of known leukocyte adhesion proteins. We used endotoxin pretreatment to create L-selectin-deficient neutrophils to study the minimum adhesive requirements for aggregation using two-color fluorescence flow cytometry. Our results implicate a lectinlike contribution to neutrophil aggregation, and suggest that L-selectin is the molecule that mediates the carbohydrate-dependent adhesive event.
我们最近报道，中性粒细胞聚集依赖于L-选择素和β2整合素Mac-1，这增加了碳水化合物相互作用在聚集中起作用的可能性。我们使用已知可抑制淋巴细胞与高内皮微静脉的L-选择素依赖性黏附的单糖和多糖，来测试这些碳水化合物是否能抑制中性粒细胞聚集。其他人发现的可抑制淋巴细胞黏附的类似类型和浓度的碳水化合物，在阻断中性粒细胞聚集方面是有效的。因此，纳摩尔浓度的多糖硫酸葡聚糖（分子量500,000）和岩藻依聚糖可抑制聚集，而硫酸皮肤素、α-卡拉胶和硫酸葡聚糖（分子量5,000）则无抑制作用。所有测试的磷酸化单糖均抑制聚集，半数有效浓度（ED50）值在8至17 mM之间，其中最有效的是甘露糖-6-磷酸和岩藻糖-1-磷酸。非磷酸化单糖葡萄糖和岩藻糖无抑制作用。岩藻依聚糖或硫酸葡聚糖（分子量500,000）的抑制作用似乎不是由于刺激后L-选择素调节的改变，因为岩藻依聚糖降低了L-选择素脱落的速率，而硫酸葡聚糖与对照相比无作用。两种碳水化合物均不抑制甲酰肽与其受体的结合。然而，碳水化合物能够与单克隆抗体竞争结合多种已知的白细胞黏附蛋白。我们使用内毒素预处理来产生缺乏L-选择素的中性粒细胞，以使用双色荧光流式细胞术研究聚集的最低黏附要求。我们的结果表明凝集素样作用对中性粒细胞聚集有贡献，并表明L-选择素是介导碳水化合物依赖性黏附事件的分子。
