Upregulation of proinflammatory cytokines and NO production in BV-activated avian macrophage-like cell line (HD11) requires MAPK and NF-κB pathways

The budded virus (BV) of Antheraea pernyi is a nuclear polyhedrosis virus (ApNPV), that belongs to the baculovirus family. It is capable of stimulating innate immune response in avian macrophage-like cells (HD11). In this study, we used the expression of proinflammatory cytokines (IFN-γ and IL-12p40) and production of nitric oxide (NO) as indicators to evaluate the involvement of the signaling cascades in the activation of HD11 cells by BV. Western blot analysis revealed that ERK1/2, p38 MAPK and JNK were phosphorylated followed by activation of p65-NF-κB after HD11 cells were challenged with BV. Inhibition of p38 MAPK and NF-κB by their respective inhibitors abolished BV-induced expression of IL-12p40, IFN-γ and production of NO, whereas inhibition of JNK abolished only the induction of cytokines. Additionally, inhibition of ERK1/2 resulted in unexpected increases in both cytokine expression and NO production. Taken together, these findings indicated that in BV-induced HD11 cells, the induction of cytokines was mediated by the p38 MAPK, JNK and NF-κB pathways, and NO production was mediated through the p38 MAPK/NF-κB pathways.