Plasma membrane cholesterol is required for efficient pseudorabies virus entry

Alphaherpesviruses comprise closely related viruses of man and animal, including herpes simplex virus, varicella-zoster virus and pseudorabies virus (PRV). Here, using methyl-beta-cyclodextrin and fluorescently tagged PRV, we directly show that depletion of cholesterol from the plasma membrane of host cells significantly reduces PRV entry. Cholesterol depletion did not reduce PRV attachment, but stalled virus particles at the plasma membrane before penetration of the cell. Cholesterol depletion results in destabilization of lipid raft microdomains in the plasma membrane, which have been shown before to be involved in efficient entry of different viruses. A significant fraction of PRV virions appears to localize juxtaposed to GM1, a lipid raft marker, during entry. Together, these data indicate that cholesterol and possibly cholesterol-rich lipid rafts may be important during PRV entry.