血管内皮细胞上内毒素特异性结合位点存在的直接证据

Direct evidences of existence of specific lipopolysaccharide binding sites on vascular endothelial cells

目的 探讨无血清因素参与下血管内皮细胞 (vascularendothelialcell,EC)与细菌内毒素 (LPS)的结合特点。 方法 用激光共聚焦显微镜观察异硫氰酸荧光素标记的LPS(FITC -LPS)与EC的结合情况 ,用氚标记的LPS(3H -LPS)与EC进行受体的放射性配基结合分析 ,计算出两者结合的平衡解离常数 (KD)和每个细胞上的结合位点数。 结果 EC与FITC -LPS的结合存在浓度、时间上的依赖性和可饱和性 ,可被过量同型LPS竞争抑制。荧光主要集中于细胞浆 ,尤其是胞浆近核周区 ,核仁也可染色。 结论 EC上存在特异性的LPS结合位点 。

Objective To investigate the binding characterastics between endothelial cell (EC) and lipopolysaccharide (LPS) without serum factors. Methods Laser confocal microscope was used to observe the binding between EC and LPS. KD and binding sites per cells were calculated by radioligand binding assay (RBA) of receptors using 3H LPS. Results The binding between EC and LPS was saturable, time and dose dependent and could be competed with overdosed LPS of the same type. The fluorescence was mainly distributed in cytoplasma, especially near the nucleus,which could also be stained. Conculsions Some specific LPS binding sites existing on ECs and LPS can function intracellularily.