Quantitation of L-selectin distribution on human leukocyte microvilli by immunogold labeling and electron microscopy
Quantitation of L-selectin distribution on human leukocyte microvilli by immunogold labeling and electron microscopy
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DOI：
10.1177/44.8.8756756
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发表时间：
1996-08-01
影响因子：
3.2
通讯作者：
Bainton, DF
中科院分区：
文献类型：
--
作者：
Bruehl, RE;Springer, TA;Bainton, DF
l -选择素是一种白细胞粘附受体，有助于中性粒细胞（PMN）在炎症部位的活化内皮上滚动，并介导淋巴细胞粘附到周围淋巴结的高内皮小静脉。该受体定位于PMN和淋巴细胞微绒毛的尖端。然而，其在这些细胞上的分布尚未被量化，其在其他白细胞上的定位和微绒毛在不同白细胞亚群上的形态测定也未被研究过。本研究采用葡聚糖沉降和密度离心从抗凝血中分离PMN和单核白细胞，用2%多聚甲醛和0.05%戊二醛固定，用免疫金标记l -选择素，包埋在Epon树脂中。l -选择素的分布通过计数金I来确定；结果显示，微绒毛上平均存在78%的PMN、72%的单核细胞和71%的淋巴细胞l -选择素，其中淋巴细胞的差异大于其他细胞类型。典型PMN和单核细胞切片有26个微绒毛，而典型淋巴细胞切片有23个。l -选择素分布和白细胞表面拓扑的定量为研究微绒毛或微绒毛定位的l -选择素在模拟微血管环境的模型系统中对白细胞系结和滚动的需求提供了基础。
L-Selectin is a leukocyte cell adhesion receptor that contributes to neutrophil (PMN) rolling on activated endothelium at sites of inflammation and mediates lymphocyte attachment to high endothelial venules in peripheral lymph nodes, Localization of this receptor to the tips of PMN and lymphocyte microvilli has been demonstrated. However, its distribution on these cells has not been quantified, and its localization on other leukocytes and the morphometry of microvilli on different leukocyte subpopulations have not been previously examined. In this study, PMN and mononuclear leukocytes were isolated from anticoagulated blood by dextran sedimentation and density centrifugation, fixed in 2% paraformaldehyde and 0.05% glutaraldehyde, immunogold-labeled for L-selectin, and embedded in Epon resin. The distribution of L-selectin was determined by counting gold I;articles on the plasma membrane of sectioned cells, and the surface microstructure of these cells was surveyed on two-dimensional transmission electron micrographs, On average, 78% of PMN, 72% of monocyte, and 71% of lymphocyte L-selectin was observed on the microvilli, with more variance on lymphocytes than the other cell types. Typical PMN and monocyte sections had 26 microvilli, whereas typical lymphocyte sections had 23. Quantitation of the distribution of L-selectin and leukocyte surface topology offers a foundation from which to study the requirement of microvilli or microvillus-localized L-selectin for leukocyte tethering and rolling in model systems that mimic microvascular environments.