Figure 3.

Dynamics of the human T-cell response after YF-17D vaccination. YF-17D replicates and exhibits a transient viremia, which stimulates the expansion of antigen-specific effector T-cells. This phase is followed by a contraction of the T-cell response, with massive death of effector populations. Finally, long-lived memory T-cells are observed after two to three months post-vaccination and remain detectable for at least 25 years. These memory populations are epigenetically poised to exert effector functions, and, after antigen re-stimulation, such as YF-17D boosters, a rapid differentiation of the effector profile is observed. However, the magnitude and quality of the remaining long-lived memory subsets are not influenced by vaccine boosters.