CD4-blockade prevents Th17 polarization.

<p>(A) Sorted TCR-transgenic cells were stimulated <i>in vitro</i> with peptide-loaded DCs under culture conditions known to preferentially polarize Th17 cells, with the addition of recombinant TGF-β, IL-6, IL-1β, and anti-IFN-γ. After 5 days of culture we observed a significant reduction of IL-17⁺ cells in the presence of anti-CD4 (n = 6, <i>P</i><0.05). In contrast, anti-CD4 addition led to an increased frequency of Foxp3⁺ T cells (n = 6, <i>P</i><0.05). (B) Representative dot plots from the two different culture conditions. An independent experiment was performed with a peptide dose of 0.3 µM with similar results.