Inactivation of HSV-2 by ascorbate-Cu(II) and its protecting evaluation in CF-1 mice against encephalitis

Ascorbate is an important antioxidant. However, in the presence of transition metals such as Cu(II) or Fe(III), it also has pro-oxidant capabilities. The effect of ascorbate-Cu(II) in the in vitro infection of herpes simplex virus type 2 (HSV-2) and its protecting effect in a murine model was investigated. HSV-2 was treated with different concentrations of ascorbate in the presence of Cu(II). A group of CF-1 mice were treated with the inactivated virus and other treated with maintenance medium containing only ascorbate-Cu(II). Weeks later, mice were challenged intranasally with infectious viruses. HSV-2 was completely inactivated by 2 mM ascorbate plus 1 mM Cu(II). Ascorbate or Cu(II) alone did not inactivate the virus. Compared with the control group, 60% of the immunized animals did not show any sign of encephalitis and survived the herpes virus infection, while a 7% survival rate was observed in the control group (P=0.056). We concluded that the in vitro treatment of HSV-2 with ascorbate-Cu(II) is not only able to inactivate the virus, but also suggested that the viral particles induced a protective response against herpes encephalitis. This inactivation may provide an alternative method to develop new agents therapeutics.