FIG 5.

Immunogenicity and efficacy of dual-antigen-expressing vectors in BALB/c mice following prime-boost vaccination. (A to C) BALB/c mice (6 per group) were immunized with 10⁸ IU of ChAdOx1 (the Mix 2× group received 2 × 10⁸ IU total virus) and boosted 6 weeks later with 10⁷ PFU MVA (the Mix 2× group received 2 × 10⁷ PFU total virus), with antigen inserts as indicated on the x axes. In ChAdOx1 vectors, the antigen was fused to the adjuvant sharkTM/Ii; in MVA vectors, the antigen was fused to tPA. A blood sample was taken in week 7 and analyzed by ICS after stimulation with a PfLSA1 (A) or PfLSAP2 (B) peptide pool. The graphs represent the frequency of PfLSA1-specific (A) or PfLSAP2 (B) CD4⁺ IFN-γ⁺ or CD8⁺ IFN-γ⁺ T cells or the summed CD4⁺ I FN-γ⁺ or CD8⁺ IFN-γ⁺ T cell responses (C). Mice were challenged with 1,000 chimeric P. berghei sporozoites expressing PfLSA1 and PfLSAP2 and monitored for development of blood-stage malaria. The bars represent median response; error bars indicate standard error of the mean. (D) Time to reach 1% parasitemia plotted on a Kaplan-Meier survival curve. All the groups showed significant increases in survival compared to naive controls above the Bonferroni-corrected threshold (P < 0.003), but no significance (n.s.) between vaccinated groups was observed.