Figure 4.

Immunogenicity and transmission reducing ability in standard membrane-feeding assay (SMFA) induced by vaccination with chimpanzee adenovirus 63 (ChAd63)–modified Vaccinia Ankara (MVA) expressing single- or dual-antigen vectors in mice. Day 70 antigen-specific IgG responses in mice after immunization with ChAd63-MVA expressing single antigens (Pfs25, Pfs230C, and Pfs28) and dual-antigen antigens linked with glycine–proline (experiment 5, n = 6/group). The figure shows the total IgG response against Pfs25 (A), Pfs230C (B), and Pfs28 (C). Response was measured by standardized ELISA (A,B), expressed in antibody units (AUs) and endpoint ELISA (C) expressed as Pfs28 endpoint titer. Median and individual data points are shown. Either a Kruskal–Wallis test followed by Dunn’s tests [(A) p = 0.0023 by a Kruskal–Wallis test, p values by Dunn’s tests are shown] or Mann–Whitney tests (B,C) were performed. Total IgG was purified from the pooled day 70 mouse serum, and each IgG was tested at three to seven different total IgG concentrations in two to five independent SMFA assays (Table S3 in Supplementary Material). The square root of antigen-specific antibody concentrations [anti-Pfs25 AU (D), anti-Pfs230C AU (E), or anti-Pfs28 ET (F)] in the feeder is shown on the x-axis. The log-transformed mean oocyst ratio between test and control (LMR) are plotted on left side of y-axis, and the associated % inhibition in oocyst density (transmission-reducing activity) is shown on the right side of the y-axis.