Co-immunization with plasmids coding the full length and a soluble form of glycoprotein D of HSV-2 induces protective cellular and humoral immune response in mice

Abstract

At present, the significance of antibody for protection of the female genital tract against infection with HSV-2 remains controversial. In the present study, the ability of a DNA vaccine encoding different forms of glycoprotein D (gD) of herpes simplex virus-2 (HSV-2) to induce simultaneously cellular and humoral responses was evaluated. Mice immunized with a plasmid encoding full length gD (pgD) developed a strong cellular immune response but weak antibody titers in serum and vaginal washings. On the other hand, mice immunized with a plasmid encoding soluble form of gD (pΔgD) showed high titers of antibodies but a very weak cell-mediated immune response. When mice were immunized simultaneously with both plasmids, cellular and humoral immune responses were elicited. This mice showed neutralizing antibodies in serum and vaginal washings as well as a high number of IFN-γ secreting cells in spleen. When challenged with 50 lethal doses of virus, mice immunized with pgD along with pΔgD showed a more complete protection than mice immunized with pgD alone. Collectively these results suggest that neutralizing antibodies help cell-mediated immune response for the protection against HSV-2 infection.