A Genetically Inactivated Herpes Simplex Virus Type 2 (HSV-2) Vaccine Provides Effective Protection against Primary and Recurrent HSV-2 Disease

Boursnell, M. E. G.; Entwisle, C.; Blakeley, D.; Roberts, C.; Duncan, I. A.; Chisholm, S. E.; Martin, G. M.; Jennings, R.; Ní Challanaín, D.; Sobek, I.; Inglis, S. C.; McLean, C. S.

A glycoprotein H (gH)-deleted herpes simplex virus type 2 (HSV-2) was evaluated as a vaccine for the prevention of HSV-induced disease. This virus, which we term a DISC (disabled infectious single cycle) virus, can only complete one replication cycle in normal cells and should thus be safe yet still able to stimulate broad humoral and cell-mediated antiviral immune responses. A gH-deleted HSV-2 virus that has been tested as a vaccine in the guinea pig model of recurrent HSV-2 infection was constructed. Animals vaccinated with DISC HSV-2 showed complete protection against primary HSV-2–induced disease, even when challenged 6 months after vaccination. In addition, the animals were almost completely protected against recurrent disease. Even at low vaccination doses, there was a high degree of protection against primary disease. A reduction in recurrent disease symptoms was also observed following therapeutic vaccination of animals already infected with wild type HSV-2.