Fig 1.
Frequency of YF-tetramer positive CD8+ T-cells in 6 singly vaccinated individuals (one individual (# 10) had 2 tetramer compatible HLA types, therefore seven lines are depicted).
A. Dot plots of a representative donor B. Frequency of YF-tetramer+CD8+ T-cells expressed as percentage of YF-tetramer positive CD8+ T-cells directed against the NS2b, NS4b and NS5 epitopes in HLA-B35, HLA-A02 and HLA-B07 positive individuals at days 0, 3, 5, 12, 28 and 180 after vaccination.
Fig 2.
Longitudinal analysis of the phenotype of YF-tetramer positive CD8+ T-cells on days 12, 28 and 180 in singly vaccinated individuals.
A Dot plots of a representative donor. Cells are gated on total CD8+ T-cells (in grey) and YF-tetramer positive cells (in black). B-D Summary of percentages of tetramer positive cells expressing CD45RA, CD27, granzyme K, granzyme B and Ki67 in 6 donors (1 donor had 2 matching HLA types). Comparisons were performed with a paired Wilcoxon Rank sum test. ns = not significant.
Fig 3.
Longitudinal analysis of T-bet eomes expression in singly vaccinated individuals.
A Dot plots of a representative donor. Total CD8+ T-cells are depicted in grey and YF-tetramer positive CD8+ T-cells in black. B-C T-bet:Eomes ratios on days 12, 28 and 180 in CD8+ tetramer+ cells. D Correlation between Granzyme K and Eomes expression and Granzyme B and Tbet expression on days 12, 28 and 180 after vaccination. E. T-bet:Eomes ratios of YF-tetramer positive at T = 180 in different subsets. Comparisons were performed with a paired Wilcoxon Rank sum test. ns = not significant.
Table 1.
Demographic characteristics of participants in prospective follow up.
Fig 4.
Percentages of YF-tetramer positive CD8+ T-cells over time in 13 healthy individuals that received a single vaccination of whom 11 were HLA A02, 2 HLA B27, 1 HLA B35 and 1 HLA B07 (2 donors had 2 HLA types compatible with tetramer reactivity).
Seven donors, 3 HLA A02, 2 HLA B07 and 2 HLA B35 had received a booster vaccination. On the x-axis the number of years since last vaccination until PBMC collection is shown. On the y-axis the percentage of YF-tetramer+ cells gated on total CD8+ T cells is shown. Black, closed symbols depict single vaccinated individuals; red, open symbols depict boosted individuals. In 4 donors tetramer+ CD8+ T cells could not be detected directly ex-vivo but only after in vitro expansion by culturing for 9 days in the presence of IL-2 and a YF-peptide pool. Analysis of the correlation between YF-tetramer+ CD8+ T cells of singly vaccinated HLA-A2+ donors and time since vaccination showed a significant negative correlation (r = -0.76, p = 0.0086, Spearman’s Rank Correlation Coefficient).
Fig 5.
Correlation between YF-Antibody titers in 99 individuals that received a single vaccination and time since vaccination.
The y-axis shows the time since vaccination and the x-axis shows the YF-serum antibody titer. The correlation between serum titer and time since vaccination was calculated with Spearman’s Rank Correlation coefficient. As a reference, the red line depicts the YF antibody serum level threshold of protection (0.5 IU/mL).