HFF were seeded to 100 % confluency, infected with CMV strain AD169, washed and incubated with two-fold dilutions of cholecalciferol, calcidiol, or calcitriol. As control, the antiviral compound Ganciclovir was used. All compounds were used in a two-fold dilution series with highest concentrations of 100 µM each. All experiments were done in triplicates (arrow bars show SEM). The dashed line indicates 50 % inhibition of CMV replication.