S. Typhi-specific activation of circulating Treg.
Net S. Typhi-specific expression of A) HLA-DR, (TD n = 5, No TD n = 4) B) PD-1, (TD n = 6, No TD n = 6) and C) CD27, (TD n = 6, No TD n = 6) on Treg. Values are shown as the mean +/- SEM. Scatter plots showing the net expression of D) HLA-DR, (TD n = 5, No TD n = 4) E) PD-1, (TD n = 6, No TD n = 6) and F) CD27, (TD n = 6, No TD n = 6) on S. Typhi-specific Treg. Means are indicated with a black horizontal line. Time points with statistically significant differences between TD and No TD volunteers (*) or among time-points within each group (#) are identified. P-values were determined using a mixed effects regression model. TD (blue squares); No TD (red circles). Values from multiple time-points were grouped together in time segments (1–4, 5–9, 10–14, and 21–28 days post-challenge) to account for variability in the numbers of samples available from each volunteer. Some volunteers had samples from multiple time-points in a time-segment resulting in more data points than the corresponding number of volunteers.