Protection from experimental ocular herpetic keratitis by a heat-killed virus vaccine

New Zealand white rabbits were given limbal inoculations of a heat-killed suspension of herpes simplex virus (HSV) in a lysate of human embryonic kidney cells. At intervals of four to 14 days, the animals were challenged by intrastromal inoculation with 10,000 plaque-forming units of viable HSV. Epithelial keratitis, disciform edema, and necrotizing keratitis with neovascularization of the cornea developed in control animals. Epithelial keratitis and corneal edema also developed in the immunized animals during the first week after virus challenge, but these symptoms rapidly resolved during the following weeks. The absence of iritis, neovascularization, and necrotizing keratitis in the corneas of the immunized animals was particularly striking.