Receptor-binding properties of a soluble form of human cytomegalovirus glycoprotein B
Receptor-binding properties of a soluble form of human cytomegalovirus glycoprotein B
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DOI：
10.1128/jvi.72.3.1826-1833.1998
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发表时间：
1998-03-01
影响因子：
5.4
通讯作者：
Compton, T
中科院分区：
文献类型：
--
作者：
Boyle, KA;Compton, T
人巨细胞病毒（HCMV）糖蛋白B（gB）（也称为gpUL 55）同源物是病毒进入和感染的细胞间传播的重要介质。为了检查gB的潜在配体结合特性，将可溶形式的gB（gB-S）放射性标记、纯化并在细胞结合实验中测试。发现gB-S与人成纤维细胞的结合呈剂量依赖性、可饱和性和特异性，Scatchard分析显示了一个双相图，估计解离常数（K-d）如下：K-d1，4.96 x 10（-6）M; K-d2，3.07 × 10（-7）hi，细胞表面硫酸乙酰肝素蛋白聚糖（HSPC）被确定为能够促进gB-S结合的一类受体，缺乏HSPG的中国仓鼠卵巢（CHO）细胞和酶促去除HSPG的成纤维细胞的gB-S结合减少了40%，而去除硫酸软骨素没有影响。然而，在不存在HSPG的情况下，显著比例的gB-S能够通过未定义的非肝素组分与细胞表面结合。gB-S与野生型CHO-K1细胞结合的结合亲和力分析显示了双相结合动力学（K-d1，9.85 x 10（-6）M; K-d2，4.03 x 10（-8）M），而gB-S与HSPG缺陷型CHO-677细胞的结合表现出单组分结合动力学（K-d，7.46 x 10（-6）M）。总之，这些数据表明gB-S与两类细胞受体相关。gB与其受体的相互作用是生理相关的，如用纯化的gB-S预处理细胞时对HCMV进入的抑制作用所证明的。这种抑制作用被确定为在病毒附着水平上表现出来。我们的结论是，SE是一个HCMV的配体介导的相互作用与细胞受体（S）在HCMV感染。
The human cytomegalovirus (HCMV) glycoprotein B (gB) (also known as gpUL55) homolog is an important mediator of virus entry and cell-to cell dissemination of infection, To examine the potential ligand-binding properties of gB, a soluble form of gB (gB-S) was radiolabeled, purified, and tested in cell-binding experiments. Binding of gB-S to human fibroblast cells was found to occur in a dose-dependent, saturable, and specific manner, Scatchard analysis demonstrated a biphasic plot with the following estimated dissociation constants (K-d): K-d1, 4.96 x 10(-6) M; K-d2, 3.07 x 10(-7) hi, Cell surface heparan sulfate proteoglycans (HSPCs) were deter mined to serve as one class of receptors able to facilitate gB-S binding, Both HSPG-deficient Chinese hamster ovary (CHO) cells and fibroblast cells with enzymatically removed HSPGs had 40% reductions in gB-S binding, whereas removal of chondroitin sulfate had no effect. However, a significant proportion of gB-S was able to associate with the cell surface in the absence of HSPGs via an undefined nonheparin component. Binding affinity analysis of gB-S binding to wild-type CHO-K1 cells demonstrated biphasic binding kinetics (K-d1, 9.85 x 10(-6) M; K-d2, 4.03 x 10(-8) M), whereas gB-S binding to HSPG-deficient CHO-677 cells exhibited single-component binding kinetics (K-d, 7.46 x 10(-6) M). Together, these data suggest that gB-S associates with two classes of cellular receptors, The interaction of gB with its receptors is physiologically relevant, as evidenced by an inhibitory effect on HCMV entry when cells were pretreated with purified gB-S. This inhibition was determined to be manifested at the level of virus attachment. We conclude that SE is a ligand for HCMV that mediates an interaction with a cellular receptor(s) during HCMV infection.