TSN pretreatment of Marc-145 cells suppresses PRRSV replication. Marc-145 cells were treated with 0.1, 0.4 or 1.6 μM TSN for 2 h prior to being infected with PRRSV NADC30-like. 48 h later, the samples were subjected to qRT-PCR (B), or IFA (C and D). Results shown in C are the mean values of percentages of PRRSV-infected cells in TSN-treated groups compared to that in the DMSO-treated control (0 µM TSN, set as 100%) from three independent experiments, and (D) is one representative IFA data set from (C). Scale bar: 100 µm. Statistical significances are denoted by * p < 0.05, **p < 0.01, and ***p < 0.001.