Figure 2 : Filorab1 vaccine is strongly immunogenic in chimpanzees.

From: The Final (Oral Ebola) Vaccine Trial on Captive Chimpanzees?

Figure 2

Top Panels: Highest serum dilution factor at which serum antibodies isolated from chimpanzees achieved 50% neutralization of (A) EBOV pseudotyped VSV and (B) RABV. Red bars IM vaccinated chimpanzees, blue bars orally vaccinated chimpanzees. Serum antibodies from all subjects except one IM vaccinated chimpanzee achieved 50% RABV neutralization at dilutions much higher than the lowest dilution factor (dashed line in (B) considered by the World Health Organization to be robustly protective against RABV challenge. No comparable standard is accepted for EBOV. Bottom Panels: ELISA optical densities (OD) for chimpanzee serum titers of IgG against (C) EBOV GP and D) RABV. Day 0, 14, and 28 OD’s for 1/150 dilutions of chimpanzee IgG are plotted as a proportion of the OD for the positive control: post-challenge IgG from macaques vaccinated with filorab1 in a previous study14. Circles are averages for the six orally vaccinated (in blue) and four IM vaccinated (in red) chimpanzees. Least squares regression lines through the orally vaccinated chimpanzee data show very close to exponential growth of IgG against EBOV GP IgG (R2 = 0.98) and RABV IgG (R2 = 0.99). Error bars are 95% confidence intervals (1.96 standard errors). Lack of confidence interval overlap between successive sampling days indicates highly significant rises in IgG on Days 14 and 28. RABV IgG titers for orally vaccinated chimpanzees grew more slowly than for IM vaccinated chimpanzees or macaques in the previous study (black X’s). EBOV GP IgG titers of orally vaccinated chimpanzees grew at a rate similar to that of macaques.