Figure 2.

Mean viral titers of MERS-CoV on days 3 and 6 after intranasal challenge of vaccinated mice with 100 LD₅₀ of MERS-CoV. Lung homogenates and total RNAs extracted from tissues of vaccinated mice at days 3 and 6 post challenge with MERS-CoV were subjected to Vero E6 cell-based infectivity assay and one-step real-time RT-PCR analyses targeting the upE gene of MERS-CoV for assessing viral loads, as previously described (5,6). A serial 10-fold diluted MERS-CoV stock with a titer of 10⁷ TCID₅₀/ml was included in parallel during the quantitative PCR assays to calculate and express the levels of upE gene expression in individual specimens as log₁₀ TCID₅₀ equivalents per gram of tissue. Alum and MF59 are adjuvant-only groups, WIV is whole inactivated vaccine (WIV) only, Alum/WIV is WIV formulated with Alum, MF59/WIV is WIV formulated with MF59. A: Vero E6-based infectious viral titers at Day 3, B: Vero E6-based infectious viral titers at Day 6, C: RT-PCR-based viral load at Day 3, and D: RT-PCR-based viral load at Day 6. * Significantly different (P < 0.01) after correcting for multiple comparisons.