MX1 and infection: Upon AIV infection, the nucleic acids of AIVs were recognized by host PRRs (RIG-I, MDA5, TLR3, and TLR7), resulting in the production of antiviral cytokines (interferon IFN α/β), interferon-induced protein (Mx-1), pro-inflammatory cytokines (IL-6), and chemokines (IL-8; Iwasaki and Pillai, 2014; Pantin-Jackwood, 2016).