Chang K P
Mol Biochem Parasitol. 1981 Nov;4(1-2):67-76. doi: 10.1016/0166-6851(81)90030-x.
A radioisotopic assay was developed to quantitate the binding of Leishmania donovani promastigotes to hamster peritoneal macrophages in vitro. The binding was temperature dependent and required no serum factors. Binding was reduced by preloading macrophages with zymosan granules or unlabeled promastigotes, but not with latex leads or opsonized erythrocytes. Binding was reduced by 10 mM EGTA that was reversible by the addition at an equimolar concentration of calcium, but not magnesium ions. Sialic acid, D-glucose, D-mannose and their derivatives reduced the binding, whereas L-fucose, D-galactose and their related sugars did not. Pretreatment of promastigotes with neuraminidase, alpha-mannosidase, alpha-N-acetylglucosaminidase or beta-glucosidase reduced their binding to macrophages. Prior trypsinization of either macrophages or promastigotes also substantially reduced the binding. At 4 degrees C, prior opsonization of promastigotes with subagglutination titers of antiserum doubled the level of binding but in combination with Protein A reduced it to 50% of its normal binding level. Prior opsonization of macrophages decreased their binding to promastigotes significantly at 4 or 37 degrees C. The results indicate that binding of Leishmania donovani promastigotes to hamster peritoneal macrophages is a ligand-receptor interaction involving their antigenic surface membrane proteins. The binding ligands of the parasites appear to have at least sialol, glucosyl, mannosyl and N-acetylglucosaminyl terminal residues as binding determinants. Thus, receptor-mediated endocytosis, defined in a broader sense, appears to be the mechanism by which leishmanias gain entry into macrophages.
开发了一种放射性同位素测定法，以定量杜氏利什曼原虫前鞭毛体在体外与仓鼠腹膜巨噬细胞的结合。这种结合是温度依赖性的，且不需要血清因子。用酵母聚糖颗粒或未标记的前鞭毛体预先加载巨噬细胞可减少结合，但用乳胶珠或调理过的红细胞则不会。10 mM 的乙二醇双四乙酸（EGTA）可减少结合，加入等摩尔浓度的钙离子而非镁离子可使其逆转。唾液酸、D - 葡萄糖、D - 甘露糖及其衍生物可减少结合，而 L - 岩藻糖、D - 半乳糖及其相关糖类则不会。用神经氨酸酶、α - 甘露糖苷酶、α - N - 乙酰葡糖胺糖苷酶或β - 葡糖苷酶预处理前鞭毛体可减少它们与巨噬细胞的结合。对巨噬细胞或前鞭毛体进行胰蛋白酶消化预处理也会显著降低结合。在 4℃时，用亚凝集效价的抗血清预先调理前鞭毛体可使结合水平加倍，但与蛋白 A 联合使用时则将其降低至正常结合水平的 50%。在 4℃或 37℃时，预先调理巨噬细胞会显著降低它们与前鞭毛体的结合。结果表明，杜氏利什曼原虫前鞭毛体与仓鼠腹膜巨噬细胞的结合是一种配体 - 受体相互作用，涉及它们的抗原性表面膜蛋白。寄生虫的结合配体似乎至少具有唾液酸、葡萄糖基、甘露糖基和 N - 乙酰葡糖胺基末端残基作为结合决定簇。因此，从更广泛意义上定义的受体介导的内吞作用似乎是利什曼原虫进入巨噬细胞的机制。
