Differences in the CD44 expression level is strengthened by polarization.

<p>(A) Representative dot plot of IL-17 and IFN-γ production by CD4^<b>+</b> T cells in non-polarized, Th1- and Th17-polarized allogeneic co-cultures for either total CD4^<b>+</b> T cells or for naïve-sorted (CD45RB^<b>high</b>) CD4^<b>+</b> T cells. Percentage of cells is indicated in the plot. Analysis was performed on day four after co-culture. (B) Representative dot plot of the CD44 surface level expression of CD4^<b>+</b> T cells in non-polarized, Th1- and Th17-polarized allogeneic co-cultures for either total CD4^<b>+</b> T cells or for naïve-sorted (CD45RB^<b>high</b>) CD4^<b>+</b> T cells. Percentage of cells within different subpopulations is indicated in the plot. Analysis of total CD4^<b>+</b> T cells was performed on day four and of naïve-sorted on day three after co-culture. (C) Percentage of CD44^<b>+++</b>CD4^<b>+</b> T cells (total CD4^<b>+</b> T cells) under different polarization conditions (n = 6–9, <i>M</i> ± SEM, Kruskal-Wallis test and <i>post-hoc</i> Dunn’s comparison, not significant). (D) Histogram overlay of geometric mean fluorescence intensity (gMFI) for CD44 of IFN-γ producers of Th1-polarized co-cultures (grey) and IL-17 producers of Th17-polarized co-cultures (black line). (E and F) GMFI for IFN-γ and IL-17 producers of different generations is shown as histogram overlay (E) and bar chart (F; n = 6, <i>M</i> ± SEM; 2-way ANOVA and <i>post-hoc</i> Sidak`s multiple comparison, **<i>p</i> ≤ 0.01, ***<i>p</i> ≤ 0.001).