DNA vaccine encoding nucleocapsid and surface proteins of wild type caninedistemper virus protects its natural host against distemper

Canine distemper virus (CDV), a member of the genus Morbillivirus induces a highly infectious, frequently lethal disease in dogs and other carnivores. Current vaccines against canine distemper consisting of attenuated viruses have been in use for many years and have greatly reduced the incidence of distemper in the dog population. However, certain strains may not guarantee adequate protection and others can induce post vaccinal encephalitis. We t ested a DNA vaccine for its ability to protect dogs, the natural host of CD V, against distemper. We constructed plasmids containing the nucleocapsid, the fusion, and the attachment protein genes of a virulent canine distemper virus strain. Mice inoculated with these plasmids developed humoral and ce llular immune responses against CDV antigens. Dogs immunized with the expre ssion plasmids developed virus-neutralizing antibodies. Significantly, vacc inated dogs were protected against challenge with virulent CDV, whereas unv accinated animals succumbed to distemper. (C) 2000 Elsevier Science Ltd. Al l rights reserved.