Primary DEF cells respond to overexpression of the CARD of Muscovy duck MDA5. The relative mRNA expression level of antiviral molecules (OAS, PKR and Mx), proinflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, IFN-α and IFN-γ) and RLR (RIG-I and LGP2) post overexpression of the CARD of Muscovy duck MDA5 by qRT-PCR. The DEF cells were transfected with either the pCAGGS-MDA5-CARD plasmid or the empty plasmid. After 36 h quantitative real-time PCR tests were performed. *The difference (P < 0.05) between the experimental and control group. Error bars indicate standard deviations.