Field trials of a very potent rabies DNA vaccine which induced long lasting virus neutralizing antibodies and protection in dogs in experimental conditions.

Kinetics of antibody responses and protection against rabies were investigated after injection of a single dose of rabies DNA vaccine and compared to those induced by one or two injections of cell culture-derived vaccine in dogs issued from the common local breed and reared in experimental conditions. Rabies DNA vaccine administered intradermally by a jet injector in the inner face of the ear was by far more efficient in inducing long lasting high titers of virus neutralizing antibodies compared to cell culture vaccine Rabisin administered either subcutaneously or intramuscularly. Four years after vaccine administration of either DNA or cell culture-derived rabies vaccines, full protection against a rabies peripheral challenge was achieved. Vaccine trials targeting dogs living in field conditions in Tunisia further established that rabies DNA-based vaccination induced a stronger induction of virus neutralizing antibodies compared to Rabisin. This report shows for the first time that DNA vaccination could be more efficient under experimental or field conditions in large size mammals than the best commercially available cell culture-derived vaccine. This improvement will hopefully allow a better rabies control in developing countries by using a more efficient vaccination with fewer doses and targeting all categories of dogs.

Post-exposure therapy in mice against experimental rabies: a single injection of DNA vaccine is as effective as five injections of cell culture-derived vaccine.

Two rabies post-exposure therapies were comparatively evaluated: BALB/c mice were challenged at day 0 with rabies virus and then received either a single dose of rabies DNA vaccine administered at day 0, or five doses of cell culture-derived rabies vaccine administered at days 0, 3, 7, 15 and 28. Both regimens, rapidly triggered protective levels of neutralizing antibodies against rabies virus in vaccinated mice. In addition, one injection of DNA vaccine protected 53% of the challenged mice, compared to 40% of mice protected after five injections of cell culture-derived vaccine. We conclude that rabies post-exposure vaccination in BALB/c mice, based on a single administration of rabies DNA vaccine might be at least as effective as five injections of cell culture-derived vaccine.