Hamamoto K, Nomura S, Suzuki M, Ohga S, Fukuhara S
First Department of Internal Medicine, Kansai Medical University, Osaka, Japan.
Thromb Haemost. 1995 Feb;73(2):291-6.
Platelets are known to internalize monoclonal antibodies directed against the glycoprotein (GP) IIb/IIIa complex. We investigated whether an antibody directed against this complex (NNKY 2-11) was transported from the surface membrane to the intracellular pool in HEL cells. Flow cytometry showed that the percent binding of NNKY 2-11 to the surface membrane of HEL cells was decreased after incubation for 24 h compared with 1 h, while the binding of an anti-GPIb antibody (NNKY 5-5) did not change. It did not seem likely that the GP IIb/IIIa complex antibody was shed from the surface membrane of the HEL cells during incubation, because the medium conditioned by incubation with these cells for 24 h showed almost no binding to washed platelets. In addition, immunoelectron microscopy demonstrated that GP IIb/IIIa complex antibodies were incorporated into the intracellular pool of HEL cells and were associated with alpha granules. These findings indicated that an anti-GP IIb/IIIa antibody could be internalized by megakaryocytes, as has been previously shown with platelets, suggesting that megakaryocyte GP IIb/IIIa may act as a carrier for various adhesion proteins.
已知血小板可内化针对糖蛋白（GP）IIb/IIIa复合物的单克隆抗体。我们研究了一种针对该复合物的抗体（NNKY 2-11）是否从HEL细胞的表面膜转运至细胞内池。流式细胞术显示，与孵育1小时相比，孵育24小时后NNKY 2-11与HEL细胞表面膜的结合百分比降低，而抗GPIb抗体（NNKY 5-5）的结合未发生变化。在孵育过程中，GP IIb/IIIa复合物抗体似乎不太可能从HEL细胞的表面膜脱落，因为与这些细胞孵育24小时后的培养基对洗涤后的血小板几乎没有结合。此外，免疫电子显微镜显示，GP IIb/IIIa复合物抗体被纳入HEL细胞的细胞内池，并与α颗粒相关。这些发现表明，抗GP IIb/IIIa抗体可被巨核细胞内化，正如之前在血小板中所显示的那样，这表明巨核细胞GP IIb/IIIa可能作为各种粘附蛋白的载体。
