Gamma Interferon Impedes the Establishment of Herpes Simplex Virus Type 1 Latent Infection but Has No Impact on Its Maintenance or Reactivation in Mice

Murine models of gamma interferon (IFN-gamma) deficiency demonstrate the role of this cytokine in attenuating acute herpes simplex virus (HSV) disease; however, the effect of IFN-gamma on the establishment and maintenance of neuronal latency and viral reactivation is not known. Using the IFN-gamma knockout (GKO) model of IFN-gamma deficiency and sensitive quantitative PCR methods, we show that IFN-gamma significantly reduces the ganglion content of latent HSV-1 in BALB/c mice, which in turn delays viral time to reactivation following UV irradiation. Similar effects were not seen in the C57BL/6 strain. These results indicate that IFN-gamma significantly attenuates latent HSV infection in the mouse model of ocular infection but has no impact on the maintenance of latency or virus reactivation.