DNA VACCINES EXPRESSING EITHER THE GP OR NP GENES OF EBOLA-VIRUS PROTECT MICE FROM LETHAL CHALLENGE

DNA vaccines expressing the envelope glycoprotein (GP) or nucleocapsid protein (NP) genes of Ebola virus were evaluated in adult, immunocomp etent mice. The vaccines were delivered into the skin by particle bomb ardment of DNA-coated gold beads with the PowderJect-XR gene gun. Both vaccines elicited antibody responses as measured by ELISA and elicite d cytotoxic T cell responses as measured by chromium release assays. F rom one to four vaccinations with 0.5 mu g of the GP DNA vaccine resul ted in a dose-dependent protection from Ebola virus challenge. Maximal protection (78% survival) was achieved after four vaccinations. Mice were completely protected with a priming dose of 0.5 mu g of GP DNA fo llowed by three or four subsequent vaccinations with 1.5 mu g of DNA. Partial protection could be observed for at least 9 months after three immunizations with 0.5 mu g of the GP DNA vaccine. Comparing the GP a nd NP vaccines indicated that approximately the same level of protecti on could be achieved with either vaccine.