The results showed that APEC significantly increased the protein expression ratio of p-p65 to p65 at 15, 30, and 60 min post-infection while CATH-2 significantly inhibited the phosphorylation of p65 and p65 expression (Figure 3A,B), indicating that CATH-2 inhibited APEC-induced NF-κB activation. Here, NFKB1 is linked to infection.