Optimization of support plasmid ratios for CCHFV rescue in BSR-T7/5.

<p>(A) BSR-T7/5 cells were transfected with 1 μg pT7-S, 2.5 μg pT7-M, 1 μg pT7-L, 0.66 μg pC-N, and 0.33 μg pC-L opti. Cell supernatants were collected and viral titers measured by determining TCID₅₀ at the indicated times post transfection. (B) In the experiments using 2:1 ratio of pC-N to pC-L opti, cells were transfected as in panel A except that 1 μg of pC-T7 was added to the transfection mix. In the experiment using a 19:1 pC-N:pC-L opti ratio, the same plasmid mix was used as for the 2:1 ratio, but with 0.95 μg of pC-N and 0.05 μg of pC-L opti. Error bars indicate means ± standard deviation. Statistical significance was evaluated using Student’s unpaired <i>t</i> test. Asterisk (*) indicates P < 0.05 at 3 days post transfection (2:1 versus 19:1). Dashed line indicates the limit of detection.