Cloning and codon optimization of a novel feline interferon omega gene for production by Pichia pastoris and its antiviral efficacy in polyethylene glycol-modified form

Feline viral diseases, such as feline panleukopenia, feline infectious peritonitis, and feline coronaviral enteritis, seriously endanger the health of cats, and restrict the development of pet industry. Meanwhile, there is a current lack of effective vaccines to protect against feline viral diseases. Thus, effective therapeutic agents are highly desirable. Interferons (IFNs) are important mediators of the antiviral host defense in animals, particularly type I IFNs. In this study, a novel feline IFN omega (feIFN-omega) gene was extracted from the cat stimulated with feline parvovirus (FPV) combined with poly(I:C), and following codon optimization encoding the feIFN-omega, the desired gene (feIFN-omega') fragment was inserted into plasmid pPICZ alpha A, and transformed into Pichia pastoris GS115, generating a recombinant P. pastoris GS115 strain expressing the feIFN-omega'. After induction, we found that the expression level of the feIFN-omega' was two times more than that of feIFN-omega (p < 0.01). Subsequently, the feIFN-omega' was purified and modified with polyethylene glycol, and its antiviral efficacy was evaluated in vitro and in vivo, using vesicular stomatitis virus (VSV) and FPV as model virus. Our results clearly demonstrated that the feIFN-omega' had significant antiviral activities on both homologous and heterologous animal cells in vitro. Importantly, the feIFN-omega' can effectively promote the expression of antiviral proteins IFIT3, ISG15, Mx1, and ISG56, and further enhance host defense to eliminate FPV infection in vivo, suggesting a potential candidate for the development of therapeutic agent against feline viral diseases.