Nucleic acid vaccine encoding gD2 protects mice from herpes simplex virus type 2 disease

Nucleic acid vaccinations with plasmids pWW65, containing the sequence for herpes simplex type 2 (HSV-2) gD2, and pRSVnt, lacking the gD sequence, were studied. Groups of mice were immunized with pWW65 alone, pWW65 plus 1,25-dihydroxyvitamin-D3 (D3), or pRSVnt. Clinical disease (vaginitis), serum and vaginal washing antibody levels, and vaginal washing virus titers were measured intravaginal HSV-2 challenge. No animals (0/10) in the pWW65 + D3 group, 6/10 animals in the pWW65 group, and 10/10 animals in the pRSVnt group developed severe disease by postchallenge day 13 (P<.001, P=.04 vs. pRSVnt). Virus titers in vaginal washings were significantly reduced in the pWW65 and pWW65+D3 groups versus the pRSVnt group (P<.001). Increasing levels of serum anti-gD2 antibodies were measured 2 and 6 days after challenge among animals in the pWW65 and pWW65+D3 groups but not among animals in the pRSVnt group. Vaccinations with a plasmid containing the gD2 gene are immunogenic and provide some protection from HSV-2-induced disease.