The interferon-inducible chemokines MuMig and Crg-2 exhibit antiviral activity in vivo

MuMig (murine monokine induced by gamma interferon) and Crg-2 (cytokine responsive gene 2) are two murine chemokines of the CXC family that are induced by the interferons (IFNs): MuMig specifically by IFN-γ, and Crg-2 by IFN-α, IFN-β, and IFN-γ. To investigate the biological roles of these chemokines, recombinant vaccinia viruses (rVVs) encoding either MuMig or Crg- 2 were constructed. In vitro, the chemokine-encoding rVVs replicated to similar levels to the control virus. Athymic nude mice inoculated with 10⁵ PFU or less of VV-HA-Mig or W-HA-Crg-2 resolved the infection successfully whereas mice given a similar dose of the control virus VV-HA-TK died from generalized infection. At higher doses, there was mortality in all groups but death was significantly delayed in mice infected with either chemokine- encoding rVV compared with those infected with the control virus. Virus- encoded MuMig and Crg-2 enhanced the cytolytic activity of NK cells and splenic cellularity by two- to threefold and resulted in significant increases in mononuclear cell infiltration in the livers of mice. Using specific neutralizing or depleting antibodies, we have established that the control of rVV replication in athymic nude mice, as a consequence of virus- expressed MuMig and Crg-2, requires NK cells and IFN-α, IFN-β, and IFN-γ.