IFNA1 and infection: On the contrary, but in concordance with results from the RNA-seq, the expression values of the ISGs determined by RT-qPCR (APOL9, IRF9, and OAS1a) during wild type VACV or VACVΔB18 infections, and independently of the addition of IFN, were similar in all cases to those detected in nontreated cells (Figure 6).