We used specific inhibitors to study the role of src-family tyrosine kinases in the maturation of human monocyte derived dendritic cells upon stimulation with several toll like receptor (TLR) agonists. The effect of these kinase inhibitors on the capacity of DC to be activated by a TLR2 (PAM3CSK4), TLR3 (Poly I:C), TLR5 (Flagellin), and TLR8 (Poly U) agonist was evaluated.

We examined whether plasmacytoid pDC are infected and/or activated by MTb, and whether they play a role in regulating bacterial clearance during acute MTb infection and if so how. We have compared these DC with myeloid DC and macrophages with respect to MTb infection.

The crude population of DC is divided into the three known splenic subsets (CD8+, CD4+, DN DC) using Fluorescence activated cell sorting (BD FACS Aria). This procedure allowed to obtain highly pure fractions of each subset. However, because DC are a very rare population, this method is very material- and cost-intensive. Furthermore, it is not surprising that the obtained cell numbers of each subset after isolation are below 107. However, these cell numbers should be sufficient for proteomic investigations. The proteomes of all three subsets using mass spectrometry is in progress.

The crude population of DC is divided into the three known splenic subsets (CD8+, CD4+, DN DC) using Fluorescence activated cell sorting (BD FACS Aria). This procedure allowed to obtain highly pure fractions of each subset. However, because DC are a very rare population, this method is very material- and cost-intensive. Furthermore, it is not surprising that the obtained cell numbers of each subset after isolation are below 107. However, these cell numbers should be sufficient for proteomic investigations. The proteomes of all three subsets using mass spectrometry is in progress.

The crude population of DC was divided into the three known splenic subsets (CD8+, CD4+, DN DC) using Fluorescence activated cell sorting (BD FACS Aria). This procedure allowed to obtain highly pure fractions of each subset. However, because DC are a very rare population, this method is very material- and cost-intensive. Furthermore, it is not surprising that the obtained cell numbers of each subset after isolation are below 107. However, these cell numbers should be sufficient for proteomic investigations. The proteomes of all three subsets using mass spectrometry is in progress.

The group completed the measurements of murine dendritic cell subsets and established an in-depth proteomic map of them. These preliminary results show more than 4500 identified proteins in each subset. All of the known markers like CD11c, CD11b, DEC-205, Langerin, etc. were found according to their differential expression pattern.

DCs pre-loaded in vitro with ICs are at least 1000-fold more potent than ICs injected directly into mice or DCs loaded with the same amount of non-complexed protein. FcgammaRs on DCs were required for efficient priming of Ag-specific CD8+ cells in vivo and induction of tumor protection.

We studied the response of human MoDC to yeast, spheroplasts, pseudohyphae and spores. Analysis of IL-6, IL-8, TNF?, IL-1?, IFN?, IL-10, IL-12p70, IL-12p40 secretion was performed with a multiplex assay.

We found that LPS-stimulated mDCs are able to induce up-regulation of co-stimulatory molecules on co-cultured pDCs. Likewise, CpG-stimulated pDCs activate co-cultured mDCs. The cross talk between these two populations of DC is very efficient since it can be observed at mDC/pDC ratio ranging from 1/10 to 10/1.

We found that LPS-stimulated mDCs are able to induce up-regulation of co-stimulatory molecules on co-cultured pDCs. Likewise, CpG-stimulated pDCs activate co-cultured mDCs. The cross talk between these two populations of DC is very efficient since it can be observed at mDC/pDC ratio ranging from 1/10 to 10/1.

The capacity of splenic DC, pulsed in vitro with protein antigens or peptides, to induce immunity was monitored after transfer into syngeneic animals. To improve existing strategies, the amplitude and polarisation of T cell responses was monitored in the presence or absence of regulatory T cells.

Down-regulation of CD83 expression on human DC through RNA interference (RNAi) results in a less potent induction of allogeneic T cell proliferation, reduced IFN-gamma secretion by established T cells and decreased capacity in the priming of functional tumor antigen-specific CD8+ T lymphocytes. In addition, CD83 mRNA-electroporated DC are stronger T cell stimulators. However, CD83 overexpression on Melan-A/MART-1-specific tumor-infiltrating lymphocytes (TIL) circumvents the need for CD83 expression on DC. Co-culture of immature DC with TIL or K562 cells overex...

These marginal zone dendritic cells, interacting with the cholera toxin (CT) adjuvant, lead to effective priming of an immune response in vivo. For the first time, we have followed adjuvant targeting of MZ DC in vivo.

These DC were matured using CpG-DNA as TLR9 ligand. Mature DCs upregulated CD80, CD86, MHC class II and produced cell type specific cytokines. Matured pDCs pDCs produced type 1 Interferons.

These DC were matured using CpG-DNA as TLR9 ligand. Mature DCs upregulated CD80, CD86, MHC class II and produced cell type specific cytokines. CD8+ myeloid DCs “cross-presented” exogeneous Ags (Ovalbumin).

DC pulsed with tumor antigens were evaluated for their immunotherapy potential in EG7-OVA and P815 tumor models. Depletion of natural regulatory T cells in tumor bearing mice resulted in rejection of P815 cells, but not EG7-OVA, suggesting that regulatory T cells have a stronger impact on immune responses against weakly immunogenic or auto-antigen (P1A).

These monocyte-derived dendritic cells are loaded with tumor lysate generated from the excised metastatic lesion of stage III/IV melanoma patients. They will be used for vaccine generation.

We have efficiently transfected DC with RNA encoding a functional protein (E/L-Selectin). The mouse E/L-S transfected DC, when given i.v., homed to the lymph nodes, whereas non transfected DC home only to the spleen.

Commercially available siRNA Smart Pool from Dharmacon targeted against the STAT3 transcription factor have been successfully transfected in these human MDDCs.

We have efficiently transfected DC with RNA encoding a functional protein (E/L-Selectin) which allows entry of DC into LN from HEV. The novel adherence capacity of human E/L-S transfected DC was demonstrated via sticking to sialyl-LewisX coated slides using a parallel plate flow microscope. RNA transfected human DC could be frozen and thawed without loosing their functionality.