Pneumococcal carriage increases the percentage of pneumococcal-responding IL-17A⁺ CD4⁺ memory T-cells in BAL and blood.

<p><b>A</b> BAL CD4⁺ memory T-cell and <b>B</b> Blood CD4⁺ memory T-cell responses from volunteers without (−, BAL n = 9, blood n = 8) or with (+, BAL n = 11, blood n = 10) experimental pneumococcal carriage (indicated on <i>x</i>-axis). Cells were stimulated <i>ex vivo</i> with or without (not shown) influenza or pneumococcal proteins as indicated. TNF⁺, IL-17A⁺ or IFNγ⁺ responses shown are background subtracted and measured as % of total CD4⁺ memory T-cells. Note the change in scale for the <i>y</i>-axis for each cytokine ns = not significant, * = <i>p</i><0.05; ** = <i>p</i><0.01 vs non-colonised volunteers.