Figure 5. Intranasal Immunization with Recombinant Adenovirus Expressing Ebola Glycoprotein Affords Protection Against Lethal Challenge Even in the Presence of Pre-Existing Immunity.

Naïve mice (n = 10) were vaccinated with a single dose of 1×10¹⁰ particles of adenovirus expressing the Ebola glycoprotein (Ad5-ZGP) by the intramuscular (I.M.), nasal (I.N.) or oral (P.O.) route. Animals in which pre-existing immunity (PEI) was established by I.M. injection of 5×10¹⁰ particles of adenovirus 5 expressing beta-galactosidase (AdlacZ) were also vaccinated in the same manner. Twenty-eight days later, mice were challenged with 200 LD₅₀ of mouse-adapted Ebola virus (Zaire strain). Data represent survival (panel A) and loss of body weight (panel B) over time and is reported as average body weight from each treatment group. Mock - age matched, untreated, unchallenged mice included in this data set to indicate normal weight variation over time. NOTE: Data for naïve mice immunized by the oral route (P.O.) and those with pre-existing immunity and vaccinated by the I.M. route (I.M.+PEI) were not included in this figure for visual clarity. All naive mice immunized orally survived challenge while none in the I.M.+PEI group survived.