TNF and infection: The qRT-PCR result showed that the infection significantly increased the mRNA levels of proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-8 (Figure 1A); the mRNA levels of cytokine IL-1β, IL-6 and IL-8 were elevated remarkably at 24hpi: IL-1β (~14 folds), IL-6 (~45 folds) and IL-8 (~105 folds), TNF-α (~83 folds).