FIG. 4.

Increasing the CAdVax vaccine dose is sufficient to overcome preexisting Ad5 immunity. Rhesus macaques were vaccinated twice at weeks 0 and 8 with an unrelated CAdVax vector to induce Ad5 immunity (gray arrows). At week 52 (black arrow), the animals were separated into three groups (n = 3) and vaccinated with 1 × 10⁸ PFU (low dose, open diamonds), 1 × 10⁹ PFU (medium dose, open squares), or 1 × 10¹⁰ PFU (high dose, open triangles) of EBO7. As a control, a group of Ad5-naïve animals was vaccinated with a low dose of EBO7 (shaded circles). Antibody titers were determined for Ad5 (black squares) and ZEBOV (open or shaded symbols) GP. Error bars show standard deviations.