Flow cytometric analysis was performed on a BD FACSCanto I (BD Biosciences), using the following antibodies for purity determination: anti-human CD14-FITC, CD4-FITC, CD8-FITC, and CD3-PE (all from BD). Viability staining was performed using the Annexin V (FITC) Apoptosis Detection Kit I (BD Pharmingen, Heidelberg, Germany) and 2.5 μg/mL propidium iodide (BD Biosciences) according to manufacturer’s instructions.

Monocytes transfected with IRAK4 siRNA or control siRNA for 20 h were matured with LPS (10 ng/mL) for 24 h and subsequently co-cultured with freshly isolated allogenic CD4+ or CD8+ T cells (at a ratio of 1:50, 1:25, and 1:12.5). Monocyte/T-cell co-cultures were incubated for 72 h and proliferation was assessed as specified below. In some experiments polyclonal anti-human IL-10 (10 μg/mL) or goat IgG (10 μg/mL) were added to the co-culture H 89 before incubation. In other experiments un-transfected monocytes were directly added to CD4+ or CD8+ T cells and co-cultures supplemented with

or without rhIL-10 at the concentrations indicated. For analysis of 3H-thymidine incorporation co-cultures of T cells (1×106 per mL) and monocytes (4×104 per mL) were stimulated for 72 h including an 18-h pulse with 1 μCi/well 3H-methyl-thymidine (Perkin Elmer, Hamburg, Germany). Proliferation corresponds to nucleotide incorporation given as counts per minute (cpm). Western blot data were measured and analyzed click here using Bio1D software from medroxyprogesterone Vilber Lourmat (Eberhardzell, Germany). Bands corresponding to specific proteins were normalized to β-actin or to the total protein amount for analysis of the ratio of phosphorylated to total protein (P-Akt and P-FoxO3a blots). The ratios of P-Akt:Akt and P-FoxO3a:FoxO3a are given as percent (%) induction calculated for stimulated samples after normalization to the unstimulated control (unstimulated control siRNA

= 100%). Reduction in gene expression levels due to siRNA-mediated knockdowns were calculated by comparing the ratios of IRAK4:β-actin or MyD88:β-actin to those obtained in control siRNA transfected cells. Statistical significance was calculated by unpaired two-tailed Student’s t-test using GraphPad Prism (Version 4.0; La Jolla, CA, USA). Significances were defined as *p ≤ 0.05, **p ≤ 0.005, and ***p ≤ 0.001. We thank all members of the laboratory for helpful discussions and assistance. This project is part of the PhD thesis of BO and was funded by the German Research Association (DFG) grants BE3841/2–1 to IBD and SFB 938 Teilprojekt C to IBD and KH, and the Olympia Morata grant of the Medical faculty of the University of Heidelberg, Germany to IBD.