Fig. 2.

Serum IgG antibody titers against 4 Ebola virus (EBOV) antigens. Endpoint dilution titers for 42 participants are shown on a log scale. Sera from participants who had previously participated in trials of investigational vaccines expressing EBOV GP (but not expressing EBOV VP40 or NP) are colored blue. The positive control serum titer from a convalescent Ebola patient is shown in red at the far right of each panel (except for panel A displaying EBOV VP40 titers and where an endpoint dilution titer was not determined for the positive control, an affinity-purified rabbit anti-ZEBOV VP40 polyclonal Ab, which was used at 1 μg/mL with good detection of antigen). Relative to the controls, the only detectable titers of IgG were in Ebola GP vaccine recipients and were against EBOV GP or whole inactivated EBOV antigens. Low background titers of ~200 or less are seen in some individuals, as report previously.