Investigations into the molecular immune response of dromedary camel, a key livestock species of the arid, have been limited due to the lack of species-specific reagents. Here we describe for the first time, the identification and characterization of type I IFNs of dromedary camel, which are the most important cytokines in the innate host immune response against viruses. We cloned camel IFN-α coding sequences and identified a total of eleven subtypes. The canonical IFN-α subtype designated as IFN-α1 contained a 555-bp Open Reading Frame encoding a protein of 184 amino acids. Recombinant IFN-α1 protein was produced in E. coli and purified from inclusion bodies. Recombinant camel IFN-α1 induced the mRNA expression of interferon-stimulated genes (ISGs) in camel kidney cells. The purified protein also showed potent in-vitro antiviral activity against Camelpox Virus in kidney cells. The identified camel IFN-α protein and the subtypes will facilitate a better understanding of the host immune response to viral infections in camel and the development of potential antiviral biologicals for zoonotic diseases for which camel act as a reservoir.
Keywords: Antiviral; Camel cell line; Column chromatography; Coronavirus; Gene walking; IFN; Inclusion body; Infection; Interferon-stimulated genes; MERS; Poxvirus; Protein refolding; RACE; Rare codons; Real-time PCR; Recombinant protein purification; Virus; Zoonotic.
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