Hill D R, Hewlett E L, Pearson R D
Infect Immun. 1981 Dec;34(3):733-8. doi: 10.1128/iai.34.3.733-738.1981.
Surface carbohydrates of Giardia lamblia were examined using six plant lectins chosen because of their specificity for major carbohydrates moieties. The binding to axenically grown G. lamblia trophozoites was assessed in both a quantitative microagglutination assay and a fluorescence assay. Of the six lectins tested, wheat germ agglutinin (WGA) agglutinated the highest percentage (22.9 +/- 3.7%) of live trophozoites, and fluorescein-labeled WGA (100 micrograms/ml) bound to 98 +/- 5% of them. Since the carbohydrate specificity of WGA includes both N-acetyl-D-glucosamine (GlcNAc) and sialic acid, inhibition experiments were performed. GlcNAc inhibited he binding of WGA to G. lamblia in both assays to a greater extent than did sialic acid. Binding of WGA was not altered by prior treatment of trophozoites with neuraminidase, suggesting that WGA was binding to GlcNAc moieties on G. lamblia and not to sialic acid. The remaining five lectins either bound nonspecifically or exhibited low percentages of binding. The apparent presence of GlcNAc but not sialic acid or other exposed surface carbohydrates may be important in the interaction of G. lamblia with its human host.
利用六种植物凝集素对蓝氏贾第鞭毛虫的表面碳水化合物进行了检测，选择这六种凝集素是因其对主要碳水化合物部分具有特异性。在定量微凝集试验和荧光试验中评估了这六种凝集素与无菌培养的蓝氏贾第鞭毛虫滋养体的结合情况。在所测试的六种凝集素中，麦胚凝集素（WGA）凝集的活滋养体百分比最高（22.9±3.7%），荧光素标记的WGA（100微克/毫升）与其中98±5%的滋养体结合。由于WGA的碳水化合物特异性包括N-乙酰-D-葡萄糖胺（GlcNAc）和唾液酸，因此进行了抑制实验。在两种试验中，GlcNAc对WGA与蓝氏贾第鞭毛虫结合的抑制作用均大于唾液酸。用神经氨酸酶预先处理滋养体不会改变WGA的结合，这表明WGA与蓝氏贾第鞭毛虫上的GlcNAc部分结合，而不是与唾液酸结合。其余五种凝集素要么非特异性结合，要么结合百分比很低。GlcNAc的明显存在而非唾液酸或其他暴露的表面碳水化合物可能在蓝氏贾第鞭毛虫与其人类宿主的相互作用中起重要作用。
