ISG15 and infection: To assess antiviral cellular responses of BPC cells to NADL and compared them with BPC cells, we chose a panel of 7 genes involved in antiviral response TLR2, TLR3, NFKB, IL6, IL8, ISG15 and MX1, and monitored by droplet digital PCR, their expression during time course of infection 0, 6, 15, 24, 30 h post-infection.