TNF and infection: To further analyze the immune responses in the chickens infected with wecB::Cm mutant, we determined the expression of selected cytokine and chemokine genes of IL-1β, IL-6, TNF-α, IFN-γ, IL-12, and CXCLi1 in the liver and spleen of chickens after infection with wild-type or wecB::Cm mutant strains, respectively.