Fig 7. SR-PLP-rSCV grew less efficiently in IFN-competent, bat-derived lung cells.

(a) For virus growth kinetics Rhinolophus alcyone lung cells, which expressed the SARS-CoV receptor human angiotensin converting enzyme (ACE)-2, were infected with rSCV and SR-PLP-rSCV at an MOI of 0.1. Supernatants were taken at 0, 24, 48 and 72 hpi, and viral replication was determined by a plaque titration assay. The experiment was performed in triplicate. Error bars indicate the standard deviations of the means. (b) RhiLu-hACE2 cells were infected with rSCV, SR-PLP-rSCV or IFN-inducing RVFV Cl 13 (control of IFN-β mRNA expression) at an MOI of 1. Total mRNA was extracted from cell lysates 24 hpi. IFN-β expression was determined using quantitative real-time PCR analysis. The mean fold change in the IFN-β expression was calculated using β-actin expression as a housekeeping/reference gene and the 2^−ΔΔCt analysis method [55]. The experiment was done in quadruplicates and repeated twice. One out of two experiments is shown. Statistical significance between the indicated groups was determined using a two-sided t test.