CREB1 and infection: In the early stage of infection, PI3K/Akt cooperated with the NF-κB pathway to promote the transcription of IL-10 by activating p50, CREB, and Ap1 transcription factors, whereas PCV2 enhances the production of IL-10 by promoting the binding of Sp1 and il10 promoter, which further activates p38 MAPK and ERK pathways at the late stage of infection [138].