CpG oligodeoxynucleotide and double-stranded RNA synergize inflammatory cytokine gene expressions in chicken monocytes (90.13)

Abstract Toll-like receptors (TLRs) recognize microbial components and initiate innate immune responses that control microbial infections. We have investigated the innate immune response of chicken monocytes to CpG-motif containing oligodeoxydinucleotide, CpG-ODN, and the analog of viral double-stranded RNA, poly I:C. Our results show ligands poly I:C and CpG-ODN of the TLR3 and TLR9, respectively, synergized the induction of many genes involving inflammatory responses including nitric oxide and cytokines, IL-1β, IFN-α, IFN-β, IFN-γ, IL-18, and IL-12, in chicken monocytes. We also demonstrated the differential responses of some cytokines such as IL-18 and IFN-β to CpG-ODN and poly I:C stimulations, respectively. Those results demonstrate differential roles for TLR3 and TLR9 in signaling immune responses to bacterial and viral infections in chicken monocytes as well as a synergistic interaction between the two signaling pathways. Furthermore, our results suggest synergistic interaction between TLR3 and TLR9 pathways may contribute the “lethal synergism” from bacterial and viral co-infections.