Design, biological activity and signaling pathway of bovine consensus omega interferon expressed in Pichia pastoris.

The bovine IFN-ω (BoIFN-ω) multigene family is located on chromosome 8, which has 14 potential functional genes and 10 pseudogenes. After aligning 14 BoIFN-ω subtypes and assigning the most frequently occurring amino acids in each position, one artificial consensus BoIFN-ω (CoBoIFN-ω) gene was designed, optimized and synthesized. Then, CoBoIFN-ω was expressed in Pichia pastoris, which was demonstrated to have 3.94-fold and 14.3-fold higher antiviral activity against VSV on MDBK cells than that of BoIFN-ω24 and BoIFN-ω3, respectively. Besides this, CoBoIFN-ω was confirmed to have antiviral activity against VSV on BL, BT, PK-15 cells, and against BEV, BHV-1, BPIV3 on MDBK cells. Additionally, CoBoIFN-ω could bind with bovine type I IFN receptors, and then activate the promoters of NF-κB, ISRE and BoIFN-ß, and induce the transcription of ISGs and expression of Mx1 and NF-κB p65, which suggested CoBoIFN-ω exerts antiviral activity via activation of the JAK-STAT signaling pathway. Overall, this research on CoBoIFN-ω not only extends and improves consensus IFN research, but also reveals that CoBoIFN-ω has the potential to be used in the therapy of bovine viral diseases.

Evolutional conservation of molecular structure and antiviral function of a type I interferon, IFN-kappa, in poultry.

IFN-kappa (IFN-κ) is a type I IFN expressed by keratinocytes, monocytes and dendritic cells with important roles during the innate immune response period. This research was conducted to elaborate the evolution and characteristics of IFN-κ in poultry. Chicken IFN-κ is located on the sex-determining Z chromosome, which is greatly different from mammals. Poultry IFN-κ cluster together in a species-specific manner through positive selection pressure and share only 19-33% homology with mammalian IFN-κ and poultry other type I IFN. Both chicken and duck IFN-κ was constitutively expressed in spleen, skin, lung, and peripheral blood mononuclear cells (PBMC), as well as being significantly induced after treatment with virus in PBMC. Biologically, poultry IFN-κ has antiviral activity against VSV in chicken embryonic fibroblasts and duck embryonic fibroblasts (CEF and DEF) cells, and induces the expression of IFN stimulated genes (ISGs). After treatment with JAK1 inhibitor, the ISGs expression can be down-regulated. Overall, our research on poultry IFN-κ not only enriches the knowledge about IFN-κ but also facilitates further research on the role of type I IFNs in antiviral defense responses in poultry.