ABSTRACT
Interferons (IFNs) have been known as antiviral genes and they are classified by type 1, type 2, and type 3 IFN. The type 1 IFN consists of IFNα, IFNβ, IFNτ, and IFNω whereas the type 2 IFN consists of only IFNγ, which is a key cytokine driving T helper cell type 1 immunity. IFNλ belongs to the type 3 IFN, which is also known as IL-28 and IL-29 possessing antiviral activities. Type 1 IFN is produced by viral infection whereas type 2 IFN is induced by mitogenic or antigenic T-cell stimuli. The IFNτ of bovine was first discovered in an ungulate ruminant recognition hormone. IFNτ belongs to the type 1 IFN with the common feature of type 1 IFN such as antiviral activity. IFNs have been mostly studied for basic research and clinical usages therefore there was no effort to investigate IFNs in industrial animals. Here we cloned porcine IFNα8 from peripheral blood mononuclear cells of Korean domestic pig (Sus scrofa domestica). The newly cloned IFNα8 amino acid sequence from Korean domestic pig shares 98.4% identity with the known porcine IFNα8 in databank. The recombinant porcine IFNα8 showed potent antiviral activity and protected bovine Madin-Darby bovine kidney epithelial (MDBK) cells from the cytopathic effect of vesicular stomatitis virus, but it failed to protect human Wistar Institute Susan Hayflick (WISH) cells and canine Madin-Darby canine kidney epithelial-like (MDCK) cells. The present study demonstrates species specific antiviral activity of porcine IFNα8.