Figure 1

Protective capacity of individual antigens against sporozoite challenge. Mice (n = 5–15/group representative of up to three independent experiments; see Table 3) were immunised with (I) plasmid DNA/recombinant protein expressing the target antigens or (II) pools of synthetic peptides representing predicted CD8⁺ and CD4⁺ T cell epitopes for each antigen formulated in AbISCO100 adjuvant. Controls were immunised with empty vector only (I), or adjuvant only (II), or not immunised (dotted line). Mice were challenged with 10³  P. yoelii cryopreserved infectious sporozoites or 10³  P. yoelii pRBC at 14 days post last immunisation. Protection was assessed by (A) qRT-PCR of Py18S rRNA in total liver RNA at 42 h after sporozoite challenge normalised against the 18S rRNA of infected but not vaccinated mice (dotted line); and (B) FCAB assay for days 3 to 30 after blood-stage challenge normalised against AUC of infectivity controls (dotted line). Data are presented as a scatter plot, with the line representing the mean and the error bars representing standard deviation (SD). Statistical comparison of immunised versus non-immunised infectivity controls was performed using one-way ANOVA followed by Bonferroni’s posthoc test, ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05. The dotted line represents the mean value for infected but non-immunised control mice used to normalise vaccinated groups and for statistical analysis.