Hoshikawa N, Ashihara Y, Shirasawa K
Acta Pathol Jpn. 1985 Sep;35(5):1069-85. doi: 10.1111/j.1440-1827.1985.tb00999.x.
The binding sites for cationized ferritin or ferritin-conjugated wheat germ agglutinin on the cell surface were studied on platelets before or after fixation in glutaraldehyde. The effects of neuraminidase on the binding sites were also demonstrated after fixation of the platelets. Changes in the binding sites and distribution pattern due to exposure to these ligands were further investigated in the unfixed platelets under a variety of conditions such as incubation time and medium. The fixed platelets incubated with either ligand showed an even and continuous distribution of particles on the cell surface. In the unfixed platelets, the ligands were rapidly moved and aggregated probably by lateral migration after binding to the cell surface. The ligands were also bound to the membrane surface and simultaneously appeared in the interior of the open canalicular system. As the binding sites were moved on the cell surface as well as into the open canalicular system, morphological changes suggestive of platelet secretion occurred. The binding sites of either ligand were redistributed on the platelet cell surface. Glycoprotein Ib, thought to be the receptor site for wheat germ agglutinin on the cell surface, contains sialic acids that contribute to the negative charge of platelets. Therefore, glycoprotein Ib may play an important role as the initial reactive site for thrombotic stimuli.
在血小板用戊二醛固定之前或之后，研究了阳离子化铁蛋白或铁蛋白偶联的小麦胚凝集素在细胞表面的结合位点。在血小板固定后，也证实了神经氨酸酶对结合位点的影响。在各种条件下，如孵育时间和培养基，对未固定血小板中由于暴露于这些配体而导致的结合位点和分布模式的变化进行了进一步研究。用任何一种配体孵育的固定血小板在细胞表面显示出颗粒均匀且连续的分布。在未固定的血小板中，配体在与细胞表面结合后可能通过侧向迁移迅速移动和聚集。配体也与膜表面结合，并同时出现在开放小管系统的内部。随着结合位点在细胞表面以及进入开放小管系统中移动，出现了提示血小板分泌的形态学变化。两种配体的结合位点在血小板细胞表面重新分布。糖蛋白Ib被认为是细胞表面小麦胚凝集素的受体位点，含有对血小板负电荷有贡献的唾液酸。因此，糖蛋白Ib可能作为血栓形成刺激的初始反应位点发挥重要作用。
