Alvarez F J, Jordán J A, Herráez A, Díez J C, Tejedor M C
Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Alcalá de Henares, Madrid, Spain.
J Biochem. 1998 Feb;123(2):233-9. doi: 10.1093/oxfordjournals.jbchem.a021927.
Previous work has shown increased uptake of hypotonically loaded rat RBCs by the spleen and liver "in vivo," suggesting that the cells of MPS are involved in their elimination from the circulation. In order to elucidate the mechanism of such elimination, we have undertaken studies on the interaction of such loaded RBCs, in comparison with native RBCs, with peritoneal macrophages. Erythrophagocytosis assays were performed in well plates to which thioglycollate-induced peritoneal macrophages had adhered. Native or loaded 51Cr-RBCs were added under different opsonization conditions to monolayer adherent macrophages, and then the amount of RBCs that were recognized was determined, with separation into adhesion and phagocytosis fractions. Native RBCs are slightly recognized by peritoneal macrophages, about one RBC per macrophage (Mphi). Osmotic treatment of rat RBCs used for encapsulation (independently of the encapsulated substance, 125I-CA or FITC-dextran) produces some modification in the erythrocyte membrane that induces higher recognition of these cells, about three loaded RBCs per macrophage. Consequently, both fluorescent (FITC-Dx) and radioactive (125I-CA) substances previously encapsulated in RBCs were transferred to M(phi)s. The fluorescence microscopic observations confirmed these results. Moreover, in the case of carrier 51Cr-cells loaded with 125I-CA, the amount of 125I-radioactivity delivered into M(phi)s was relatively higher than that of 51Cr. The highest ratio, 125I-CA (encapsulated substance)/51Cr-RBCs (carrier cells), present in M(phi)s means there was a stronger interaction with macrophages of RBCs that carry a higher amount of encapsulated CA, as a function of the heterogeneity of the loaded rat RBCs population previously reported. Finally, the adhesion and phagocytosis of loaded RBCs seem not to involve complement receptors or Fc receptors on the macrophages.
先前的研究表明，低渗加载的大鼠红细胞在“体内”被脾脏和肝脏摄取增加，这表明巨噬细胞系统的细胞参与了它们从循环中的清除。为了阐明这种清除机制，我们进行了研究，比较了这种加载的红细胞与天然红细胞与腹膜巨噬细胞的相互作用。在巯基乙酸诱导的腹膜巨噬细胞粘附的孔板中进行红细胞吞噬试验。将天然或加载了51Cr的红细胞在不同的调理条件下添加到单层贴壁巨噬细胞中，然后确定被识别的红细胞数量，并分为粘附和吞噬部分。天然红细胞被腹膜巨噬细胞轻微识别，每个巨噬细胞约识别一个红细胞（Mphi）。用于包封的大鼠红细胞的渗透处理（与包封物质125I-CA或FITC-葡聚糖无关）会对红细胞膜产生一些修饰，从而诱导对这些细胞的更高识别，每个巨噬细胞约识别三个加载的红细胞。因此，先前包封在红细胞中的荧光（FITC-Dx）和放射性（125I-CA）物质都转移到了巨噬细胞中。荧光显微镜观察证实了这些结果。此外，在加载了125I-CA的载体51Cr细胞的情况下，传递到巨噬细胞中的125I放射性量相对高于51Cr。巨噬细胞中存在的最高比率，即125I-CA（包封物质）/51Cr-红细胞（载体细胞），意味着携带更高量包封CA的红细胞与巨噬细胞的相互作用更强，这是先前报道的加载大鼠红细胞群体异质性的函数。最后，加载红细胞的粘附和吞噬似乎不涉及巨噬细胞上的补体受体或Fc受体。
