人类疱疹病毒-6型包膜胆固醇对病毒感染作用

Role of cholesterol in envelope of human herpesvirus-6A on virus infectivity

目的研究人类疱疹病毒-6型(HHV-6A)包膜胆固醇在病毒感染宿主细胞过程中的作用。方法用不同浓度甲基-β-环糊精(MβCD)作用于HHV-6A GS株,经20%蔗糖缓冲液梯度离心,去除甲基-β-环糊精并纯化病毒,分别感染HSB-2和Jurkat细胞,采用免疫荧光实验(IFA),流式细胞术及免疫蛋白杂交等方法检测病毒在去除胆固醇后,对宿主细胞的结合、融合、进入的影响。结果当HHV-6A包膜胆固醇被10 mmol/L甲基-β-环糊精去除后,未检测到抗-即时早期蛋白(IE1)的表达,其感染性遭到破坏,但可以部分被外源性胆固醇所恢复,50 mmol/L的外源胆固醇就可以使经2.5 mmol/L MβCD处理的病毒部分恢复其感染力。与未经MβCD处理的HHV-6A比较,病毒尚能结合宿主细胞,其结合能力稍微受到了影响,但病毒不能进入靶细胞,其感染性及诱导细胞融合的能力显著减弱。结论HHV-6A包膜胆固醇在细胞融合过程中起着重要作用,同时也是病毒进入宿主细胞的关键因素。

Objective To study the role of cholesterol in the envelope of human herpesvirus-6（HHV-6） when they enter host cells.Methods HHV-6A GS strains were treated with different concentrations of methyl-β-cyclodextrin（MβCD）.The treated virus was subjected to ultracentrifugation through a 20% sucrose cushion to remove MβCD and purified virons,then HSB-2 and Jurkat cells were infected by treated HHV-6A respectively.The roles of HHV-6A binding host cells,induced cell-fusion and the ability of entry were examined by using IFA,flow cytometry and Western blotting post HHV-6A cholesterol depeletion.Results When cholesterol was removed from HHV-6 virions with 10mmol/L MβCD,the expression of IE1 was not detected,the infectivity was abolished,but it could be partially rescued by the addition of exogenous cholesterol.50 mmol/L may partially restored the infectivity of HHV-6 treated with 2.5 mmol/L MβCD.Compared with untreated with MβCD,HHV-6 binding was affected slightly by MβCD treatment.In contrast,envelope choleste rol depletion markedly affected HHV-6 infectivity and HHV-6-induced cell fusion.Conclusion Cholesterol present in the HHV-6 envelope plays a prominent role in the fusion process and is a key component in viral entry.