At the earlier stage of infection (12 h and 24 h p.i.), the binding activity of NF-κB p50 with the il10 promoter in PCV2-Rep1-infected cells was similar to that in the PCV2-infected cells, but was not detected in PCV1- or PCV1-Rep2-infected cells (Figure 6A,C); the binding activity of Sp1 with the il10 promoter showed the same results (Figure 6B,D). Here, IL10 is linked to infection.