For the purposes of data analysis raw data replicates that were below the detection limit of the assay (ten copies) were given an arbitrary value of 1. Primers used are listed in Supporting Information Table 1. A total of 96-well polystyrene microtiter plates (Nunc, Roskilde, Denmark) were coated overnight at 4°C with 100 μL of antibody solution in 0.05 M carbonate buffer (pH 9.6) at 1 μg/mL. Subsequently, the plates were washed three

times with find protocol PBS (pH 7.2) +0.05% Tween 20 and blocked overnight at 4°C with carbonate buffer +2% BSA (pH 9.6). The serum samples were titrated by tenfold dilution from 1:10 to 1:10 000 in PBS+1% BSA and 0.2 % Tween 20, added to the wells and incubated for 1 h at room temperature. Following another wash with PBS (pH 7.2) +0.05% Tween 20 the plates were incubated for 1 h at room temperature with HRP-conjugated mouse anti-human IgG monoclonal antibodies DAPT clinical trial (BD Pharmingen, Brϕndhy, Denmark, Cat no. 555788) in 1:4000 dilution. Enzyme activity was assayed by incubation for 30 min at room temperature with 100 μL of tetra methyl benzidine (TMB) plus substrate per well. To stop the reaction, 100 μL of 0.2 M sulfuric acid was added, and the OD was measured at 450 and 620 nm for background subtraction. Comparisons between groups were assessed by the Kruskal–Wallis and Dunnett’s multiple comparisons test. The Mann–Whitney two-tailed t-test was used for analyses within groups. In all instances, a

p value <0.05 was considered significant. We would like to acknowledge Drs Gebeyehu Haile and Fekede Lemma from Hossana and Butajira hospitals for their contribution in the selection and screening of patients, Ato Alemayehu Kifle for bleeding and collecting specimens from these sites. We appreciate AHRI's administration for the support they provided when needed. The study was funded by EU INCO contracts ICA-CT-1999-10005, IC4-2001-10050, EU FP6 contract LSHP-CT-2003-503367 and the institutes' core budgets.

AHRI is supported by the governments of Ethiopia, Sweden and Norway. Conflict of interest: The authors declare no financial or commercial conflict of interest. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. “
“The NF-κB/Rel family member c-Rel was described to be Reverse transcriptase required for the development of TH1 responses. However, the role of c-Rel in the differentiation of TH17 and regulatory CD4+Foxp3+ T cells (Treg) remains obscure. Here, we show that in the absence of c-Rel, in vitro differentiation of pro-inflammatory TH17 cells is normal. In contrast, generation of inducible Treg (iTreg) within c-Rel-deficient CD4+ T cells was severely hampered and correlated to reduced numbers of Foxp3+ T cells in vivo. Mechanistically, in vitro conversion of naive CD4+ T cells into iTreg was crucially dependent on c-Rel-mediated synthesis of endogenous IL-2.