Virus-specific effects of recombinant porcine interferon-gamma and the induction of Mx proteins in pig cells.

Interferon-alpha (IFN-alpha) and -gamma differed in their action against influenza virus and vesicular stomatitis virus (VSV) on pig cells. Recombinant IFN-alpha severely impaired the cytopathic effect of VSV on PK-15 cells, whereas recombinant porcine IFN-gamma did not. IFN-alpha impaired also the replication of VSV and of influenza virus in primary pig kidney cells in contrast to IFN-gamma, which failed to induce an efficient antiviral state against both viruses. Otherwise, the IFN system seemed to work properly in pig cells since both IFN-alpha and IFN-gamma induced an efficient antiviral state to mengovirus. The establishment of the antiviral state to VSV and influenza virus correlated with the induction of two cytoplasmic proteins related to the murine Mx protein involved in the selective resistance of mice to influenza virus infection. The results are discussed in the context of the susceptibility of pigs to influenza virus strains that are in circulation in birds and in humans.