Importance of cholesterol for infection of cells by transmissible gastroenteritis virus

In this study, we addressed the question whether cholesterol is important for transmissible gastroenteritis virus (TGEV), a porcine coronavirus, in the initiation of an infection. We found that cholesterol depletion from the cellular membrane by methyl-beta-cyclodextrin (MbetaCD) significantly impaired the efficiency of TGEV infection. Infectivity was also reduced after depleting cholesterol from the viral envelope. This finding is surprising because coronaviruses bud from a pre-Golgi compartment which is expected to be low in cholesterol compared to the plasma membrane. Addition of exogenous cholesterol resulted in a restoration of the infectivity confirming our conclusion that efficient TGEV infection requires cholesterol in both the viral and the cellular membranes. Our data raise the possibility that the viral and cellular proteins involved in the entry process may be associated with cholesterol-rich membrane microdomains.