RIPK2 and escherichia coli infection: Pairwise comparisons were performed as follows: shRIP2 (knockdown of RIP2 HD11 cells) vs. WT (complete HD11 macrophages) and shRIP2 + APEC (knockdown of RIP2 HD11 cells combined with avian pathogenic E. coli infection) vs. APEC (avian pathogenic E. coli infection HD11 cells).