Determination of virus titres of the vaccinated animals.

<p>Groups of 3 IFNAR^−/− mice were immunized three times at three weeks intervals with 5, 20, or 40 μg of the cell culture based vaccine. The control group of IFNAR^−/− mice (n = 3) was mock immunized with phosphate buffered solution (PBS). All animals were challenged with 1,000 PPFU (400 LD50) of CCHF virus Turkey-Kelkit06 strain two weeks after the last immunization. All animals were sacrificed at 2 days post-infection. Virus was isolated from the blood (A), liver (B) and spleen (C) as described in the Materials and Methods. Each point represents the mean values of the viral titre of three animals, and the standard deviations are shown as error bars.