However, nothing is known about metabolites of the tryptophan catabolism on DC function. CD14+ cells were isolated from periperal blood and activated to fully mature DC in vitro. In parallel cultures, DCs were generated in the presence of different concentrations of kynurenine and quinolinic acid. These mature DC were used to analyse expression of differentiation markers by FACS, to stimmulate naïve T-cells to proliferation, and to induce Th-1 T-cell selleck inhibitor response. Kynurenine, but not quinolinic acid, had a dramatic effect on the expression of the DC maturation marker CD83, suggesting that kynurenine has an impact on DC maturation.

The expression of MHC-class I molecules, the co-stimulatory receptors CD80/CD86 and CCR7 on DC was not affected by kynurenine or quinolinic acid. In further analysis we found that kynurenine treated DC dramatically decrease the ability of T-cells to produce INF-gamma a key cytokine indicating a Th-1 immune response. Subsequently T-cell subpopulations were analysed and found that the portion of CD4+CD25+ T-cells was selleck significantly increased in the T-cell population generated by kynurenine treated DC, which indicate an increase in a suppressor Caspase inhibitor T-cell population. In summary, these data suggest that kynurenine “primed” mDC induce generation of suppressor T-cells. Based on the data

presented above we hypothesize that metabolites of the kynurenine pathway are important determinants in turning the immune system especially DC to a tolerogenic phenotype. Poster No. 54 Impact of Hypoxia on Furin Trafficking and the Formation of Invadopodia Dominique Arsenault 1 , Sébastien GrandMont1, Martine Charbonneau1, Kelly Harper1, Claire M. Dubois1 1 Department of Pediatric, Immunology Division, Université de Sherbrooke, Sherbrooke,

QC, Canada Recent studies indicate that tumoral invasion and metastasis, triggered by the hypoxic microenvironment, involves strategic relocalization of convertases, adhesion molecules, and metalloproteases. We used the highly invasive human Palbociclib purchase fibrosarcoma cells HT-1080, stably transfected with eGFP-tagged-furin in order to study the impact of hypoxia on the cellular localization of the convertase furin. Our results indicate that in hypoxic cells, furin is relocalized at the plasma membrane and is internalized via both clathrin- and caveolin/raft dependent endocytosis. Using furin trafficking mutants, we demonstrate that filamin-A, a cytoskeletal tethering protein, is essential for the membrane localization of furin under hypoxia. We further demonstrate that in hypoxic cells, furin and its substrate MT1-MMP relocalize to specific pericellular compartments and this relocalisation is associated with an increased cell ability to convert pro-MT1-MMP into its active form.