Figure 2.

CD4 T cell phenotype in serum-free RPMI. Human peripheral blood naïve CD4 T cells were purified by negative selection and cultured for five days with plate-bound anti-CD3 and soluble anti-CD28. Additional treatment groups included Th17-inducing cytokines (IL-1β, IL-6, IL-23, TGF-β), AhR agonist (FICZ, 200 nM) or AhR antagonist (CH223191, 4 uM), as indicated. On day 5, T cells were restimulated with PMA and ionomycin in the presence of brefeldin A for 4 hours, stained with fluorescent-labelled antibodies and analyzed by flow cytometry. Shown are representative dot plots of CD4 versus FoxP3 on live cells (top) or IL-22 versus IL-17 on CD4⁺ FoxP3⁻ cells (bottom).