Figure 2. Tetravalent CYD vaccination induces mostly CD8⁺ YF-17D NS3-specific responses YF-17D NS3-specific CD4⁺ (left) and CD8⁺ (right) T cell responses in CYD-TDV vaccinees (top) and placebo controls (bottom). Geometric mean (GM) interferon-gamma (IFNγ) and tumor-necrosis-factor-α (TNFα) production in CD4 (CD3⁺CD8^-) (left) and CD8 T cells (right) following ex vivo stimulation of whole blood with YF-17D NS3 peptides in dengue vaccine group (top) and placebo group (bottom panel) before and 28 d after the first, before and 28 d after the third vaccination, and 1 y after the last vaccination (V07) as measured by ICS. For each subject, first the background cytokine levels in the negative control (medium+DMSOs) were subtracted from YF-17D NS3 peptide pool A and B stimulated cytokine levels. Second, the responses from pool A and pool B were combined by taking the higher percentage of the two pools for each subject. Responses shown are the geometric mean cytokine percentages of these combined results.(A) Percentages of IFNγ⁺ or TNFα⁺ CD4 cells in adult and adolescent vaccinees (B). Percentages of IFNγ⁺ or TNFα⁺ CD4 cells in adult and adolescent placebo recipients (C) Percentages of IFNγ⁺ and TNFα⁺ CD8 cells in adult and adolescent vaccinees. (D) Percentages of IFNγ⁺ and TNFα⁺ CD8 cells in adult and adolescent placebo recipients