Louis, MO, USA). Sections were counterstained with Hematoxylin. Splenocytes

from naive BALB/c mice were enriched AZD0530 for CD4 or for CD8 by means of magnetic cell sorting and labeled with CFSE (Molecular Probes Invitrogen) as previously described 27. Subsequently, cells were incubated with plate-bound anti-CD3 and anti-CD28 antibodies and PI concentrations of 0, 12.5, 50 or 200 μg/mL. Th polarizing experiments were designed based on a previous publication 10. In short, CD62Lhi purified naïve CD4 T cells (CD4+CD62L+ T-cell isolation kit Miltenyi Biotec, Bergisch Gladbach) were cultured at 1×106 cells/mL with 10 μg/mL anti-CD3 and 10 μg/mL anti-CD28. For Th1 polarization cells were stimulated in the presence of IL-12 (10 ng/mL) and anti-IL-4 (10 μg/mL; purified from 11B11 hybridoma). Th2 polarizing conditions included IL-4 (10 ng/mL, R&D Systems), anti-IFN-γ (5 μg/mL; purified from

XMG1.2 hybridoma) and anti-IL-12/23 p40 (5 μg/mL; purified AZD2281 mouse from C17.8 hybridoma). Treg induction was performed with TGF-β (20 ng/mL; Preprotech, Rocky Hill, NJ), 10 nM retinoic acid (Sigma), anti-IL-4 (10 μg/mL) and anti-IFN-γ (5 μg/mL). For Th0 conditions no cytokines or antibodies were added. Th17 conditions included TGF-β (20 ng/mL), anti-IL-4 (10 μg/mL), anti-IFN-γ and IL-6 (20 ng/mL). At 72 h cytokine levels were measured in the supernatant using ELISA (murine IL-2 from BD Pharmingen; murine IL-17 coat with clone TC11-18H10.1 and detection clone TC11-8H4, Biolegend). To detect IL-4 secretion, cells were washed and restimulated with 5 ng/mL phorbol ester 4-phorbol-12-myristate-13-acetate (PMA, Sigma-Aldrich) and 100 ng/mL CAI (A23187, Sigma-Aldrich). At 24 h after restimulation murine IL-4 was detected by ELISA

with coat clone 11B11 and detection (BVD6-24G2). For analysis of division the CFSE-labeled cells were stained with fluorescently labeled anti-CD4 or anti-CD8 antibodies and CFSE peaks were analyzed by flow cytometry. For analysis of signal transduction pathways, cells of a T-cell line DN32.D3 (hereafter referred to as DN32), kindly provided by Prof. Clomifene Dr. Richard Blumberg (Harvard University, Boston, USA), were used. DN32 cells were stimulated with 5 ng/mL phorbol ester 4-phorbol-12-myristate-13-acetate (PMA, Sigma-Aldrich) and 100 ng/mL CAI (A23187, Sigma-Aldrich) in the presence of 0, 12.5, 25, 50 or 100 μg/mL PI. At 24 h IL-2 concentrations were measured in the supernatant by means of ELISA (BD Biosciences Pharmingen). After 1, 3 and 5 h of incubation with PI 50 μg/mL IL-2 mRNA levels were measured by means of quantitative PCR or cells were harvested to obtain cell lysates. DCs were derived from BALB/c BM as previously described 27.