Protection of pigs against classical swine fever with DNA-delivered gp55

Classical swine fever virus causes significant mortality and morbidity in c ommercial piggeries in many countries in Europe and Asia. The protective an tigen, gp55, is highly conformation-dependent and thus killed virus or bact erially produced proteins are not protective. This report demonstrates that DNA vaccination with the gene encoding gp55 can provide protective immunit y with inoculation of two doses of 25 mu g DNA or a single shot of 200 mu g . Furthermore, the DNA can be delivered intramuscularly or by a simple spri ng-loaded needleless inoculator. In addition it is shown that inoculation o f the DNA at a single site conveys the same level of immunity as division o f the dose between two sites. (C) 2000 Elsevier Science Ltd. All rights res erved.