Suppression of CTLA-4 by Th17 polarising cytokines is not specific to IL-17+ T cells.

<p>CD4+CD25- T cells were stimulated in the presence of Th17 polarising cytokines for four days and assessed for IL-17, IFNγ, IL-21, TNFα, IL-2 or Foxp3 in combination with CTLA-4 by flow cytometry. <b>A)</b> Frequency of total CTLA-4+ cells. <b>B)</b> Representative bivariate FACS plot of CTLA-4 versus IL-17 for cells cultured under Th17 polarising conditions. <b>C)</b> CTLA-4 expression in CTLA-4+ T cells gated according to IL-17 expression. <b>D)</b> CTLA-4 expression by CTLA-4+ T cells that expressed IL-17, IFNγ, IL-21, TNFα or IL-2. <b>E)</b> CTLA-4 expression in CTLA-4+ T cells defined by FoxP3 expression. In C, D and E expression under Th17 conditions is expressed relative to the level under Th0 conditions. Data are summarised for n≥7 donors. Bars indicate median values and error bars show the semi interquartile range. Significance with respect to cells expressing the marker under Th0 conditions was tested by Wilcoxon matched paired tests. (* = P<0.05, ** = P<0.01, *** = P<0.001).