CD44 expression level discriminates allo-reactive IL-17⁺ and IFN-γ⁺ CD4⁺ T cells.

<p>(A) Cytokine production in CD4^<b>+</b> T cells four days after allogeneic co-culture with bone-marrow derived dendritic cells. Percentage of cells is indicated in the dot plot. (B) CD44 subpopulations of CD4^<b>+</b> T cells and cytokine production within these subpopulations four days after allogeneic co-culture. (C) CD44 expression level of <i>in vitro</i> generated IFN-γ^<b>+</b>CD4^<b>+</b> (grey) and CD4^<b>+</b>IL17^<b>+</b> T cells (black line). Values for the geometric mean fluorescence intensity (gMFI) for CD44 are indicated in the histogram. (D) CD44 expression level (gMFI) of <i>in vitro</i> generated IL-17^<b>+</b>CD4^<b>+</b> and IFN-γ^<b>+</b>CD4^<b>+</b> T cells (n = 13, <i>M</i> ± SEM, Wilcoxon rank sum test). (E) IL-17 and IFN-γ production prior to as well as seven, 14 and 28 days after allogeneic skin transplantation (n = 3–4, <i>M</i> ± SEM, 2-way ANOVA and <i>post-hoc</i> Sidak`s multiple comparison). (F) CD44 expression level of <i>in vivo</i> formed IFN-γ^<b>+</b>CD4^<b>+</b> (grey) and CD4^<b>+</b>IL17^<b>+</b> T cells (black line) from lymph nodes after transplantation (skin-tx) and without transplantation (w/o). GMFI for CD44 is indicated in the histograms. (G) CD44 expression level (gMFI) of <i>in vivo</i> formed IL-17^<b>+</b>CD4^<b>+</b> and IFN-γ^<b>+</b>CD4^<b>+</b> T cells from spleen prior to as well as seven, 14 and 28 days after transplantation (n = 3–4, <i>M</i> ± SEM, 2-way ANOVA and <i>post-hoc</i> Sidak’s multiple comparison. (H) CD44 expression level (gMFI) of <i>in vivo</i> formed IL-17^<b>+</b>CD4^<b>+</b> and IFN-γ^<b>+</b>CD4^<b>+</b> T cells from lymph nodes after transplantation (n = 3–4 <i>M</i> ± SEM, 2-way ANOVA and <i>post-hoc</i> Sidak’s multiple comparison). Statistical significance (<i>p</i>) is within the groups is indicated in the figures (*<i>p</i> ≤ 0.05, **<i>p</i> ≤ 0.01, ***<i>p</i> ≤ 0.001).