Abstract: Objective To study the effect of methyl-β-cyclodextrin on the cholesterol content and the expression of glycoprotein in the envelope of human herpesviru-s6(HHV-6).Methods HHV-6AGS strains were treated with 0,1,2,3,5,10 mmol/L different concentrations of MBCD.The treated virus was subjected to ultracentr ifugation through a 20% sucrose cushion to remove MBCD and purified virons,then the cholesterol content of treated HHV-6A was measured with cho lesterol assay kit.HSB-2 cells were infected by treated HHV-6A,the expression of viral glycoprotein in the envelope of HHV-6A by using Western blotting post HHV-6A cholesterol depeletion.Results Cholesterol was removed from HHV-6 virions with MBCD,the content of cholesterol decreased from 35μg/ml to 10μg/ml below,and was negative relate to the concentration of MBCD,the expr ession of envelope glycoprotein was not changed post HHV-6A cholesterol depeletion compared with untreated with MBCD.Conclusion MBCD can remove the cholesterol in the HHV-6 envelope,but the expression of envelope glycopro- tein was not affected when cholesterol absent.