We are currently performing gene silencing experiments in human monocyte-derived DCs (MDDCs) with the dual aim of generating relevant knowledge on (i) the transcriptional regulation of DC differentiation, and (ii) the safe and rationale in vitro manipulation of gene expression in DCs.

These dendritic cells were generated with interferon-beta and interleukin-3. They were used in a clinical trial in melanoma patients who were randomized to receive immunizations either with these I3 DC or with G4 DC (DC generated with GM-CSF and IL-4).

We performed co-cultures of IFN-DCs with zoledronate-stimulated gamma delta T lymphocytes. Gamma delta T-cell activation, as demonstrated by their up-modulation of activation marker expression levels (e.g. CD25 and CD69), was observed. The studies demonstrated for the first time the existence of a bidirectional activating interaction between DCs and gamma delta T lymphocytes activated by aminobiphosphonates.

We identified a novel DC subset called IKDC producing IFNg and expressing TRAIL which can recognize and kill transformed tumor cells in vitro and in vivo. Cultures were generated of tumor cells with IKDC producing IFNg and expressing TRAIL which can recognize and kill transformed tumor cells in vitro and in vivo. IKDC generate long contacts and synapses with tumor cells and ultimately kill them within 4 hours.

These DC were generated by culturing enriched monocytes for 5 days.

These DC were used in a maturation step for subsequent production of a DC vaccine.

These cells acquire a mature phenotype along with an enhanced secretion of several cytokines/chemokines. Moreover, these DCs are very potent in inducing naive CD4(+) T cells to differentiate into interferon-gamma (IFN-gamma)-secreting type 1 T helper (Th1) cells.

These cells do not acquire a mature phenotype and do not lead to an enhanced secretion of several cytokines/chemokines.

These DC were used to elicit CTL responses in a mouse model.

Indium labelled E/L-S DC (without antigen loading) is administered i.v. to a patient to study the reaction with regard to DC migration.

We are defining the differential roles of intestinal lymph DC subsets in activation of naïve and memory T cells. Two of the three DC subsets are highly potent activators of naïve CD4+ T cells, and do not appear to be constitutively suppressed in any way.

Since LPS-activated DC are potent inducers of NK cell priming and lymph nodes appear to be a key place in which DC and NK cell interactions occur, we have investigated the in vivo capacity of resting and DC-primed NK cells to reach the draining lymph nodes.

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 assessed the capacity of the electroporated DCs to activate naive HLA-A2-restricted MelanA-specific CD8(+) T cells without the addition of any exogenous cytokines. A >500-fold increase in MelanA-specific CD8(+) T cells was observed when compared with immature DCs, and a >200-fold increase when compared with cytokine cocktail-matured DCs. In correlation, we found a marked increase in cytolytic and IFN-gamma/tumor necrosis factor-alpha (TNF-alpha) secreting CD8(+) T cells. Our data indicate that immature DCs genetically modified to express stimulating molecul...

Dendritic cells were matured with TNF alpha, IFN gamma and PGE2. These DC were used to produce a DC vaccine.

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).

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.

The question was addressed of whether bLf, whose immunomodulant properties are now recognized, could influence MDDC differentiation/activation.

These monocyte-derived DCs received combined stimulation with TLR ligands. They were used in our study on DC activation by pathogen-derived stimuli.

We investigated the interactions between human monocyte derived DCs (MDDC), generated in the presence of GM-CSF and IL-4 (IL-4 DC), and antigen-stimulated circulating gamma delta T lymphocytes, bearing the Vgamma2 TCR.