Immunization of dogs with a DNA vaccine induces protection against rabies virus

Rabies is a fatal encephalomyelitis which is transmitted to man, mostly by dogs in developing countries. This zoonosis can be prevented by vaccination of humans before or after exposure. However, a more radical approach is po ssible, involving the elimination of the principal vector/reservoir by vacc inating dogs, The vaccine must be effective, safe and inexpensive. Mass pro duction of plasmids is possible and DNA-based immunization with a plasmid e ncoding the antigen responsible for inducing protection seems to be more co st-effective than classical techniques involving cell culture. Beagles were immunized by intramuscular (i.m.) injection with a plasmid encoding the ra bies virus (PV strain) glycoprotein. Neutralizing antibodies against both w ild-type rabies virus and European Bat Lyssaviruses (EBL1 and EBL2) were de tected after a single injection and a boost, but levels of neutralizing ant ibodies against EBL1 were low. Moreover, all vaccinated dogs were protected against a lethal challenge with a wild-type dog rabies strain. This is one of the first studies to demonstrate that dogs can be protected by DNA vacc ines, and opens important perspectives for rabies control. (C) 1999 Elsevie r Science Ltd. All rights reserved.