The effect of immunization with herpes simplex virus glycoprotein D fused with interleukin-2 against murine herpetic keratitis.

PURPOSE To evaluate the preventive effect of vaccination using fusion protein (gD-IL-2) consisting of herpes simplex virus type 1 (HSV-1) glycoprotein D (gD), and human interleukin-2 (IL-2), and plasmid DNA encoding gD-IL-2 against murine herpetic keratitis. METHODS Plasmid containing gD-IL-2 (pHDLneo1) was constructed, and gD-IL-2 peptide was purified. BALB/c mice were injected hypodermally or subconjunctivally twice with 1 microg/0.1 mL of gD-IL-2 peptide, or subconjunctivally twice with 90 microg/0.05 mL of gD-IL-2 plasmid DNA. Neutralizing antibody titer and delayed-type hypersensitivity (DTH) against HSV-1 were measured. Immunized mice were challenged with CHR3 strain of HSV-1 into the cornea. Clinical manifestations of the epithelial and stromal keratitis were scored. RESULTS Stromal keratitis was inhibited in gD-IL-2 peptide- or DNA-immunized mice; however, epithelial keratitis was not. It was confirmed that plasmid gD-IL-2 elicited significant virus neutralizing titer in sera and DTH response. CONCLUSION Vaccination with gD-IL-2 was effective against murine herpetic keratitis.