Immune Protection of Nonhuman Primates against Ebola Virus with Single Low-Dose Adenovirus Vectors Encoding Modified GPs
Figure 3
Determination of Lowest Vaccine Dose for Immune Protection against Ebola Virus Challenge by Adenoviral Vector GP/NP Vaccine
(A) Kaplan-Meier survival curve of macaques: Immunization was with rAd vectors expressing GP(Z) and NP(Z) (109–1011, three animals per group; control and 1012, one animal each), and challenge was performed with the Kikwit strain of Zaire ebolavirus as in Figure 2A.
(B) Immune responses in immunized animals. Intracellular flow cytometry was performed to quantify TNF-α production from Ebola-specific CD4+ (left graph) or CD8+ (right graph) lymphocytes, respectively, from animals immunized as indicated. Immune responses were measured at 3 wk postimmunization. Circles, diamonds, and squares indicate responses for individual animals. Horizontal line indicates the average of individual responses in the immunization group. Results represent the percent cytokine positive in the gated lymphocyte group and background stimulation (DMSO alone) has been subtracted from each sample ( p-values obtained using unpaired Student's t-test; n.s., not significant).
(C) Antibody responses in immunized animals. Anti-GP ELISA titers (left graph) and serum neutralizing antibody responses (right graph) were measured as described in Methods.