Cloning, Prokaryotic Soluble Expression, and Analysis of Antiviral Activity of Two Novel Feline IFN-? Proteins

Wang, Xiaona; Li, Fengsai; Han, Meijing; Jia, Shuo; Wang, Li; Qiao, Xinyuan; Jiang, Yanping; Cui, Wen; Tang, Lijie; Li, Yijing; Xu, Yi-Gang

Recombinant feline interferon-ω (rfeIFN-ω) was the first licensed immunomodulator for use in treating viral infections in cats, especially FIV and FeLV infections [17, 18, 45] . Furthermore, rfeIFN-ω also exhibits therapeutic effects against other feline viral infections, such as FCV, feline parvovirus, and feline herpesvirus-1 [45] , as well as viruses that originate in other animals, such as foot-and-mouth disease virus, influenza virus, BVDV, VSV, PRV, and rotavirus [6, 12, 18] . In this study, our results demonstrated that both rfeIFN-ωa and rfeIFN-ωb had antiviral activity in homologous animal cells (F81 cells, cat) and heterologous animal cells (Vero cells, monkey; MDBK cells, cattle; MDCK cells, dog; PK-15 cells, pig), indicating that rfeIFN-ωa and rfeIFN-ωb have broad cross-species antiviral activity in vitro, similar to previously published findings in MDBK and MDCK cells [12] . In contrast, the antiviral activities of rfeIFN-ωb in homologous and heterologous animal cells were better than that of rfeIFN-ωa. Intriguingly, the rfeIFN-ωa and rfeIFN-ωb proteins exhibited antiviral activity in MDCK cells, despite the absence of IFN-ω in canines [46, 47] . We speculate that different IFNs with different physiological functions are likely responsible for the difference of results obtained in our study compared to other published studies. Furthermore, analysis of the broad-spectrum antiviral activities of rfeIFN-ωa and rfeIFN-ωb revealed that they were effective against VSV, FCoV, PEDV, BVDV, and CPV. Out of those five viruses, antiviral activity was strongest against VSV and FCoV. No significant differences in antiviral activity against CPV, BVDV, or PEDV were observed between rfeIFN-ωa and rfeIFN-ωb. However, the overall broad-spectrum antiviral activity of rfeIFN-ωb was significantly stronger than that of rfeIFN-ωa.