T-cell polarization depends on concentration of the danger signal used to activate dendritic cells.

Although several studies have focused on allergic sensitization by dendritic cells, to date it is still open under which conditions these antigen-presenting cells are able to induce an allergic immune response. Our study reveals that BMDCs pulsed with LPS-free ovalbumine did not induce allergic disease. However, when BMDCs were activated with low-dose LPS during pulsing with allergen, these cells expressed an inflammatory set of cytokines and co-stimulatory molecules like CD86 and OX40L. Moreover, activated cells were able to prime mice for massive eosinophilic inflammation of the lung, airway hyper-reactivity, IgE production and production of Th2 cytokines by lymphocytes. Blocking experiments showed that expression of OX40L is not involved in induction of Th2 response. Interestingly, BMDCs that were activated with high dose of LPS lose their Th2-sensitizing capacity. Instead these cells induce a Th17 type immune response. We conclude that presentation of allergen by dendritic cells generated with GMCSF is not sufficient to lead to induction of allergic immune response. Further activation of BMDCs is required to prime mice for allergic immune response. In this study, we show that LPS is a suitable stimulus. However, when cells were activated with high dose LPS they tended to induce a Th17 response.

Transcription factor HNF1beta and novel partners affect nephrogenesis.

Heterozygous mutations of the tissue-specific transcription factor hepatocyte nuclear factor (HNF)1beta, cause maturity onset diabetes of the young (MODY5) and kidney anomalies including agenesis, hypoplasia, dysplasia and cysts. Because of these renal anomalies, HNF1beta is classified as a CAKUT (congenital anomalies of the kidney and urinary tract) gene. We searched for human fetal kidney proteins interacting with the N-terminal region of HNF1beta using a bacterial two-hybrid system and identified five novel proteins along with the known partner DCoH. The interactions were confirmed for four of these proteins by GST pull-down assays. Overexpression of two proteins, E4F1 and ZFP36L1, in Xenopus embryos interfered with pronephros formation. Further, in situ hybridization showed overlapping expression of HNF1beta, E4F1 and ZFP36L1 in the developing pronephros. HNF1beta is present largely in the nucleus where it colocalized with E4F1. However, ZFP36L1 was located predominantly in the cytoplasm. A nuclear function for ZFP36L1 was shown as it was able to reduce HNF1beta transactivation in a luciferase reporter system. Our studies show novel proteins may cooperate with HNF1beta in human metanephric development and propose that E4F1 and ZFP36L1 are CAKUT genes. We searched for mutations in the open reading frame of the ZFP36L1 gene in 58 patients with renal anomalies but found none.