NFKBIA and coinfection: As shown in Fig. 9, comparing with cell control, the protein levels of IκBα and cytoplasmic p65 in virus group at 12 hpi were significantly decreased, and the levels of p-IκBα and p65 in the nucleus were increased, indicating that PRRSV/PCV2 co-infection induced the translocation of NF-κB from the cytoplasm to the nucleus, indicating the activation of NF-κB pathway.