Schlepper-Schäfer J, Kolb-Bachofen V
Faculty of Biology, University of Konstanz, Federal Republic of Germany.
Blood Cells. 1988;14(1):259-74.
Binding and uptake studies of in vitro aged or senescent rat erythrocytes by isolated rat liver macrophages suggest recognition by galactose-specific receptors on the cell surface of the macrophages. We analyzed carbohydrates exposed on old erythrocytes by plant lectins in an agglutination assay in comparison with freshly isolated untreated erythrocytes. Rat erythrocytes aged in vitro by storage are agglutinated by a panel of lectins that do not react with freshly isolated erythrocytes. Specificity of agglutination was shown by inhibition with monosaccharides. Antibodies eluted from senescent rat erythrocytes agglutinate in vitro aged as well as senescent rat erythrocytes, but not freshly isolated cells nor human erythrocytes. Galactose-specific lectins isolated from rat liver give similar results; they also agglutinate normal human erythrocytes. Agglutination by the liver lectin is inhibitable by galactose and N-acetylgalactosamine but not by N-acetylglucosamine or mannose. Furthermore, rat liver macrophages devoid of galactose-specific receptors show markedly reduced binding of senescent rat erythrocytes. We conclude that recognition of old rat erythrocytes is mediated by two systems: old erythrocytes expose different terminal sugar residues or a different arrangement of glycans when compared to young erythrocytes, rendering them recognizable by liver lectins and by autoantibodies.
对分离出的大鼠肝脏巨噬细胞摄取和结合体外老化或衰老大鼠红细胞的研究表明，巨噬细胞表面的半乳糖特异性受体参与了识别过程。我们通过凝集试验，利用植物凝集素分析了老化红细胞表面暴露的碳水化合物，并与新鲜分离的未处理红细胞进行了比较。体外储存老化的大鼠红细胞可被一组凝集素凝集，而这些凝集素与新鲜分离的红细胞不发生反应。单糖抑制试验表明了凝集的特异性。从衰老大鼠红细胞中洗脱的抗体可凝集体外老化的以及衰老的大鼠红细胞，但不能凝集新鲜分离的细胞或人类红细胞。从大鼠肝脏中分离出的半乳糖特异性凝集素也得到了类似结果；它们同样能凝集正常人红细胞。肝脏凝集素引起的凝集反应可被半乳糖和N-乙酰半乳糖胺抑制，但不能被N-乙酰葡糖胺或甘露糖抑制。此外，缺乏半乳糖特异性受体的大鼠肝脏巨噬细胞对衰老大鼠红细胞的结合能力明显降低。我们得出结论，对衰老大鼠红细胞的识别由两个系统介导：与年轻红细胞相比，衰老红细胞暴露了不同的末端糖残基或聚糖排列方式，从而使其能被肝脏凝集素和自身抗体识别。
