FOS and infection: In addition, the gene expression in the MAPK signaling pathway in our study (e.g., MyD88, AP-1, c-fos, Jun, JunD, MAX), and cytokines (IL-1β, IL-6, IL-8) were increased after infection in resistant chickens, and the expression levels of MAP2K4 and MAPK11 were higher in resistant H5N1-infected chickens than in susceptible H5N1-infected Ri chickens (Supplementary Table S7).