4.10. Real-Time RT-PCR
Total RNA was extracted from the culture supernatant of CSFV-infected PK-15 cells using a TRIzol reagent (catalog no. 15596026; Invitrogen, Waltham, MA, USA). The isolated RNA was then reverse transcribed to cDNA with reverse transcriptase XL (AMV) (catalog no. 2621; TaKaRa, Dalian, China) according to the manufacturer’s instructions. Genomic copies of CSFV were quantified by a real-time RT-PCR assay as described previously [25]. The experiment was carried out in triplicates.