Figure 2.
Protein/AS01B platform induces a more robust and Th2-skewed PfRH5-specific CD4+ response than ChAd63-MVA vaccination
PBMCs from days 0, 7, 14, and 63 were stimulated with medium alone or a PfRH5 peptide pool for 24 h, then stained and analyzed, identifying PfRH5-specific cells as those co-expressing CD25 with OX40, CD137, or CD69 following stimulation. Frequencies of CXCR5+ (cTfh cells), Th1 (CXCR3+CCR6−), Th2 (CXCR3−CCR6−), and Th17 (CXCR3−CCR6+) were also quantified within RH5-specific CD4+CD45RO+ cells (all gating as in Figure S4).
(A) Frequencies of PfRH5-specific cells within CD45RO+CD4+ T cells were compared between each time point between trials.
(B–F) Within the PfRH5-specific CD45RO+CD4+ T cell population, the proportion of cells that were CXCR5+ cTfh (B), CXCR3+CCR6− (Th1) (C), CXCR3−CCR6− (Th2) (D), CXCR3−CCR6+ (Th17) (E), or the ratio of Th1:Th2 cells (F) was also compared between platforms at each time point.
(G–L) A multiplex bead-based assay was then used to measure the supernatant concentrations of cytokines, and the Th1/Th2/Th17 skew of the cytokine response was determined by calculating ratios of IFN-γ:IL-5 (G), IFN-γ:IL-17A (H), IFN-γ:IL-4 (I), IL-5-IL-17A (J), IL-4:IL-17A (K), and IL-2:IFN-γ (L) in supernatants from day 63 PBMCs.
In (A), all of the available samples were analyzed (ChAd63-MVA/protein/AS01B): day 0, n = 15/57; day 7, n = 15/20; day 14, n = 15/57; and day 63, n = 11/22. In (B–F), samples were excluded if the total number of PfRH5-specific CD45RO+CD4+ T cells was <50 (ChAd63-MVA/protein/AS01B): day 7, n = 12/20; day 14, n = 14/56; and day 63, n = 10/21. A multiplex assay (G–L) was run on a subset of samples (ChAd63-MVA/protein/AS01B): day 63, n = 9/15. Comparisons between trials were performed using Mann-Whitney tests. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001, and ∗∗∗∗p < 0.0001. In all of the panels, each point represents a vaccinee. Lines denote medians and interquartile ranges.