Turkey adenovirus 3 (TAdV-3) is the causative agent of an immune-mediated disease in turkeys, haemorrhagic enteritis, through targeting B lymphocytes. In the present study, we investigated the role of sialic acid in TAdV-3 entry and characterized the structural components of TAdV-3 receptor(s) on RP19, B lymphoblastoid cells. Removal of the cell-surface sialic acids by neuraminidases or blocking of sialic acids by wheat germ agglutinin lectin reduced virus infection. Pre-incubation of cells with Maackia amurensis lectin or Sambucus nigra agglutinin resulted in virus reduction, suggesting that TAdV-3 uses both α2,3-linked and α2,6-linked sialic acids as attachment receptor. Virus infectivity data from RP19 cells treated with sodium periodate, proteases (trypsin or bromelain) or metabolic inhibitors (dl-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol, tunicamycin, or benzyl N-acetyl-α-d-galactosaminide) indicated that N-linked, but not O-linked, carbohydrates are part of the sialylated receptor and they are likely based on a membrane glycoprotein, rather than a glycolipid. Furthermore, our data, in conjunction with previous findings, implies that the secondary receptor for TAdV-3 is a protein molecule since the inhibition of glycolipid biosynthesis did not affect the virus infection, which was rather reduced by protease treatment. We can conclude that terminal sialic acids attached to N-linked membrane glycoproteins on B cells are used for virus attachment and are essential for successful virus infection.

中文翻译：

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土耳其腺病毒3，一种腺病毒，使用N-连接糖蛋白上的唾液酸作为细胞受体。

土耳其腺病毒3（TAdV-3）是通过靶向B淋巴细胞在火鸡，出血性肠炎中引起免疫介导疾病的病原体。在本研究中，我们调查了唾液酸在TAdV-3进入中的作用，并表征了RP19，B淋巴母细胞上TAdV-3受体的结构成分。神经氨酸酶去除细胞表面唾液酸或小麦胚芽凝集素凝集素阻断唾液酸可减少病毒感染。用黑果黑胶凝集素或黑接骨木预先培养细胞凝集素导致病毒减少，表明TAdV-3使用α2,3-连接的和α2,6-连接的唾液酸作为附着受体。从RP19细胞病毒感染性数据用高碘酸钠，蛋白酶（胰蛋白酶或菠萝蛋白酶）或代谢抑制剂（处理DL -苏式-1-苯基-2-癸酰氨基-3-吗啉代-1-丙醇，衣霉素，或苄基ñ -乙酰基α - d -galactosaminide）表明ñ -连接的，但不是ö碳水化合物是唾液酸化受体的一部分，它们很可能基于膜糖蛋白而不是糖脂。此外，我们的数据与先前的发现相结合，暗示TAdV-3的二级受体是一种蛋白质分子，因为糖脂生物合成的抑制作用不会影响病毒感染，而通过蛋白酶处理可以减少这种感染。我们可以得出结论，附着在B细胞上N-连锁膜糖蛋白上的末端唾液酸用于病毒附着，对于成功感染病毒至关重要。