Graabaek P M
J Ultrastruct Mol Struct Res. 1986 Feb;94(2):176-87. doi: 10.1016/0889-1605(86)90064-9.
Mannose-specific binding sites in the two types of synoviocytes (A and S) from the synovial membrane of normal rat knee joints were studied by an ultrastructural-cytochemical method using horseradish peroxidase (HRP) as a ligand. The A cells showed mannose-specific binding sites for HRP which were localized in coated pits and coated vesicles (110 nm) as well as in smooth-walled vesicles, vacuoles, and tubules. No mannose-specific binding sites for HRP were detected in the S cells. Together with previous observations on absorption of intraarticularly injected HRP in type A and type S synoviocytes, the present results strongly support the interpretation that the A cells internalize HRP by receptor-mediated endocytosis and that the S cells internalize HRP by fluid-phase endocytosis only. The present results agree with the suggestion that mannose-specific binding sites consist of two pools, the one concerned with internalization of ligand and the other with intracellular targeting of internalized ligand.
采用辣根过氧化物酶（HRP）作为配体的超微结构细胞化学方法，研究了正常大鼠膝关节滑膜中两种滑膜细胞（A 型和 S 型）的甘露糖特异性结合位点。A 型细胞显示出 HRP 的甘露糖特异性结合位点，这些位点定位于被膜小窝和被膜小泡（110 纳米）以及光滑壁小泡、液泡和小管中。在 S 型细胞中未检测到 HRP 的甘露糖特异性结合位点。结合先前关于关节内注射的 HRP 在 A 型和 S 型滑膜细胞中吸收的观察结果，目前的结果有力地支持了以下解释：A 型细胞通过受体介导的内吞作用内化 HRP，而 S 型细胞仅通过液相内吞作用内化 HRP。目前的结果与以下观点一致，即甘露糖特异性结合位点由两个池组成，一个与配体的内化有关，另一个与内化配体的细胞内靶向有关。
