FIG 5.

Reactivity of a DENV-specific CD4⁺ T cell megapool. (A) Percentages of CD4⁺ T cells that produced IFN-γ upon stimulation with the CD4⁺ megapool (CD4⁺-MP) for donors previously vaccinated with TV005 (n = 9). IFN-γ production of CD4⁺ T cells stimulated with a CD8⁺ megapool (CD8⁺-MP) was used as a control. The dotted line at 0.02% represents the cutoff for positivity. The average (± standard error of the mean [SEM]) response for all cohorts is shown. Statistical significance was determined using a two-tailed Wilcoxon test. (B) Staining of the memory CD4⁺ T cell subsets and IFN-γ-producing cells of a representative donor. Memory subsets were defined as naive T cells (CCR7⁺ CD45RA⁺), central memory T cells (T_CM) (CCR7⁺ CD4⁺ 5RA⁻), and the two effector memory subsets (T_EM and T_EMRA) (CCR7⁻ CD45RA⁻ and CCR7⁻ CD4⁺ 5RA⁺), according to their expression of the indicated markers. (C) The relative IFN-γ response for each memory T cell subset was measured by ICS after stimulation with the CD4⁺-MP (n = 9).